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					Perspectives                                                                                              in                      Nutrition


            Ecological                                                                       Factors                                              in             Nutritional                                                                    Disease

                                                                                             NEVIN              S. SCRIMSHAW,                              PH.D.,           M.D.*



                                 I      T     is hoped                 that        Perspectives                    in     Nutrition               will      review          the         literature                  selectively,          in-
                                            terpret             it moderately                        and           present         a spectrum                    of ideas              that          will        serve        as a continual
                             stimulation                        to        nutritional                   research        applied              to    medical             problems.




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            EDICINE                         has         always                      been            concerned            with                     and           environmental                                    factors                influence                  both           the
                 the             cause                of             disease.                      In        modern          aca- agent      and the host       and                                                      may,             in turn,       determine
demic            medicine,        however,                                          the cause                      of a disease the      nature     and    outcome                                                          of          the    interaction                           be-
is too           often     equated         with                                       the agent                      of the    dis-tween      agent    and    host.
ease.             From                  an          epidemiologic                               point               of view                the           Just         as identifying                               the         agent      of an infectious
agent            is      merely                     one              of       a triad               whose                two           other disease                   is not    sufficient                              to      describe      its cause,                              so
components                              are        host               factors                and         environmental                            the  agent                      of     nutritional                    disease,     the                         deficiency
factors.                Neither   the presence     of a pathogenic                                                                                of a specific                        nutrient,                   is not sufficient                             to explain
agent            nor the deficiency       of an essential       nutrient     the occurrence                                                                                                        of the disease.                           For example,                           to
alone             determines      whether      or not     disease        willwhat    extent                                                                                                      is a dietary                            deficiency      of                      iron
occur.                                                                       the cause      of                                                                                              hypochromic,                              microcytic                     anemia.
     For          example,          what       is the     cause       of tubercu-      The    iron     intake        of   a person             with     such      an
losis ?             If it were             merely       infection        with        the
                                                                                       anemia      might        be quite        adecjuate          were     it not
tubercle              bacillus,         nearly      all of us would               long for the abnormal           iron   loss resulting            from    severe
since             have        contracted            the      clinical       disease. hookworm            disease ; or       from        excessive         phos-
Yet         we         know                 that            most                 of us          who            have             worked            phates               in          the   diet    interfering                                        with            iron             ab-
extensively                           with             sick                people               have               experienced                    sorption              ;         or from     abnormal                                    blood             loss       due            to
repeated                     entries                       of             tubercle                  bacilli                into              ourmenorrhagia,                            a        duodenal                     ulcer         or       a      hemolytic
lungs            without                      contracting                               clinical               tuberculosis.                      disorder,                 or         even               from           an      excessive                  loss        of      iron
The      same      exposure,         however,         in a malnourished              in sweat.          Environmental                and      host      factors        may
or     otherwise           susceptible            person          might        have make        a given          intake         of the          nutrient            wholly
resulted         in death          from       acute       febrile       tubercu- adequate             or grossly          deficient.            In other           words,
losis.                                                                               it is the interaction               of host,         agent       and       environ-
    Infection         is obviously            not     synonymous              with ment        which       causes       the      disease.
disease.           Host       factors        combine            with      the      in- Too       often       the      medical          student            and       young
fectious                agent                  to          produce                        the           clinical                disease,          house           officer               is encouraged                            to      identify                the         agent
                                                                                                                                                  of disease       and                              then            to        concentrate                         on      thera-
  From       the             Department         of Nutrition     and                                            Food Science,                     peutic     action                                  against                   the       agent.                         Because
Massachusetts                      Institute       of Technology,                                                  Cambridge,                     modern                clinical                     medicine                    has        developed                         effec-
Massachusetts.                     Contribution         No.   549.                                                                                tive          counter                          measures                     against               the            agents                  of
    *Professor                     of             Nutrition,                   Head,            Department                        of
                                                                                                                                                  most            diseases,                        this          approach                       generally                    works
Nutrition                  and          Food            Science.
                                                                                                                                                  well           in         the              hospital.                        However,                      it         may             fail
    Presented                    at         Colloquium                    “Man            and           Environment,”
Albert          Einstein                    College                  of       Medicine,                  New            York,           New       miserably                       in        preventing                        a relapse                  once           the       pa-
York,        May            27,         1963.                                                                                                     tient          returns                    to      the      environment                            from            which              he

American               .Tournal               of      Clinical                   Nutrition                                             112                                                                                    Vol. 14,           February              1964
                                                                                    Ecological                                     Factors                       in         Nutritional                                 Disease                                                                      113


came,                    and                as          an           approach                                    to             prevention                            came
                                                                                                                                                                       of                to        much                  the         same                conclusions.                     He          also
disease                   in         a population,                                      it           is irrational                              and           usu- emphasized                                the    importance                                   of the                        high    level
ally           ineffective.                                  Preoccupation                              of        public                   health                     of normally                           nonpathogenic                                    organisms                         in grossly
authorities                                 with              the              agent                        as         the              cause          of contaminated
                                                                                                                                                            a                                                    foods               fed          to         young                      children                   in
disease                       is      likely                  to         result                       in         control                      measures    these        areas.
which                    are              uneconomical                                       or         ineffective                             because                     The            newly                  recognized                        syndrome                              of        weanling
they                do         not           attack                      the             disease                       at          a      vulnerable                  diarrhea                          occurs                 because                      of          the            synergism                             of
link           in        the          chain              of multiple                                   causation.                                                     malnutrition                               and            infection.                              It         is most                 promi-
       Weanling                              diarrhea                          is            a        good                  example.                            Asnent     in the                               second               year              of        life             because               various
Gordon’                             has    pointed                       out   for the      first                                                 time            environmental
                                                                                                                                                                  in                                               and               host              factors                       combine                       to
a recent                           review,       in                  most    of the    technically                                                          un-cause                     a peak                   of      both             malnutrition                      and            massive
derdeveloped                                 areas                   of             the                 world                      there                 is   aenteric                        infection                    during                  the            weaning                       and           post-
characteristic                                   increase                           in                the              frequency                            of weaning                             period.                     It      should                be         noted                that           during
diarrheal                           disease                   at         the             time                 of           weaning                      which this                  time                  the            children                      are              being                  exposed                       to
is        an             epidemiologic                              rather                           than                   an            etiologic                   many                 organisms                            of      varying                         pathogenicity                 for
entity.                             Microbiological                                 studies                           of           this             syn-              the          first            time                and            possess                    little              acquired                         im-




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drome         give      exceedingly                                                          varied      and    equivocal     munity.
results.         Depending          upon                                                        the population         stud-     The    vital    statistics                                                                                  of      a country,                                which               are
ied,     only      from      20 to 40                                                         per   cent     of cases      canof course       the same                                                                               ones           compiled                           and        used              by
be      accounted                                for         by          known                         pathogens.                                  Shigel- the                   international                                 health              agencies,                         do        not          reveal
las,           pathogenic                               strains                      of              Escherichia                                 coli          and thetrue                         basis       for              diarrheal                    disease                    in preschool
salmonellas                                 are         found                      in            this            decreasing                             order children.                                    They                   indicate                     only                    that      gastro-
of        frequency.                              Most                   viral                    studies                        have              failed             intestinal                         disease                is     the         most                  common                       cause              of
to        show                     that           the           proportion                                    of           enteric                  viruses death                             in the                     one       to              four    year      age                                     group.
is      higher                        in          children                          with                     weanling                            diarrhea   Public                            health                   authorities                    have    tended                                   to      con-
than    in those        without.                                                                                                                                      elude              from                these              data              that              they               should                 stress
    The    characteristic                                                    feature                         of            the            syndrome                    the         construction                                 of latrines                       and               sanitary                  water
is      that                   the           diarrhea                           occurs                           when                   the             supply supplies                            to      prevent                     infection.
of    breast                         milk     is                   no           longer       adequate                                         for               the In              the            rural               highland                   Indian                      village               of Santa
nutritional                             needs                      of          the     child      and                                      when                  theMaria                     Cauqu#{233} in                    Guatemala,                                   the          Institute                     of
supplementary                                     or          substitute                                   feeding                      provided                      Nutrition                            of          Central                     America                            and              Panama
is      both                   grossly                   deficient                               in         protein                        and             other (INCAP)                                   has                 managed                            experimentally                        to
nutrients                             and              contaminated                                              by               poor              sanita- apply                        the             conventional                             public                     health                 measures
tion.                     In              addition                           the                  child                    is          more                likely for             controlling                             enteric                   infection                         far           more               in-
to         be             playing                        in              the                 dirt                and                   even              to            be
                                                                                                                                                                      tensively                           than                 could               be              carried                      out               on              a
coming      in                                direct                   contact                                   with           feces.        national
                                                                                                                                              At                                                   scale.       After                       three                years               there     still               has
the    same                                  time                   his      growth                                         and      develop- been     no                                          recognizable                            decrease                          in      diarrheal                    dis-
ment                 have                   come                    to         a             virtual                            standstill                        ease
                                                                                                                                                                 be-                in        children                     under                  five           years                of        age          in        the
cause                    of           nutritional                       deficiency,                                   and                 fatality                    village.
rates                from                   other                   infectious                                   diseases                        are           also         The            measures                        instituted                            have                included                     safe
high.                          The                     data                    indicate                                    that                  although             drinking                          water,                  a       sanitary                             privy              for           every
diarrhea                           can           be       associated                                    with                known                      patho- house,        the   full-time      services      of a sanitary             in-
gens                in             some                cases,                  in                a         greater                        number              spector,
                                                                                                                                                               of             and    the establishment            of a clinic        with
cases                the              diarrhea                          is       due                  to          organisms                             which a nurse         and    doctor     in attendance.              These        did
normally                             would                    not              be             pathogenic                                   in          a wellnot       reduce       morbidity          from    diarrheal         disease
nourished                           host.                                                                                                                     when        no associated         nutritional        measures          were
       Sabin,’                       in       a paper      presented                                                   in         Geneva                      last taken                      or          changes                       in          food                     preparation             and
February                            at       the    United        Nations                                                         Conference                          handling                     made                within               the        home.                          Spread                 of        the
on        the             Application                                   of         Science                         and              Technology                diarrheal                        disease                          was          shown                      to     be            by contact
for        the                 Benefit                   of         the              Less                    Developed                                 Areas, within                       the family                          group,           not              by          water            or flies.
114                                                                                                                                   Scrimshaw


        In      a similar                       village,                     Santa                   Catarina,                        in        which       toward                       disappearance                                  of               a          disease.                            Until
no medical    or sanitary         changes                                                                    were   introduced                              relatively                      recently                               beriberi                        was     not                an         impor-
but  in which    the     children       were                                                                  given     a dietary                           tant            problem                              in         rural                  areas               of        Thailand          aI1d
supplement                               containing                     30           gm.               of         good              quality                 Malaya,                      but                small                 mechanical                               mills,              which                    are
protein                   per            day           plus             other                   nutrients,                          there               wasbeing                   introduced                                   extensively,                           do              a            more
a decrease                            in the                      duration,                          severity                       and              fre-efficient    job     of                                       polishing                             the          rice             than               hand-
quency     of                      diarrheal                       disease                       over     the                    same             time pounding,          which                                        had been      the                              standard                       method
period.                       It     is obvious                              that               the          search                 for         an in-   for generations.                                                The  result                                 has     been                    a tragic
fectious                   agent                of      diarrhea                           in the                  weanling                          child increase                      in            beriberi,                           particularly                the             infantile
and             identification                              of           a           known                         pathogen                            in form.                    In          the               latter                    case              the          mother’s                           milk              is
some               cases            did          not             really                 lead            to        an          understand-                   so       deficient                         in            thiamine                           that           many                   breast-fed
ing           of          the            causation                                 of          the            syndrome                           ;   this
                                                                                                                                                        infants      become        suddenly            ill and           die    within       a
required                      recognition                              of          the           multiple                        factors             in-matter       of hours.
volved.                                                                                                                                                     Kwashiorkor            and       marasmus                  are      also     in-
   The               occurrence                             of any                       disease                    depends                      upon creasing          in many         of the          burgeoning              cities     of
all three                   factors-agent,                                 host     and                      environment.                               Latin      America       and      Africa          because           women      are




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One     of                 the      clearest                             indications                             of this                        is theweaning           their  children          earlier,         either       in imita-
way                 in             which                    the                 prevalence                   and                 nature                     tion        of         the            more                     well-to-do                           or        in      order                 to         work
of       disease                    varies                  with                time,                  place                  and           person.         at      industrial                          or           domestic                           jobs.                  Unfortunately,
The             operation                             of          these                   factors                       can           be              illus- because                     of            ignorance                                 and               poverty,                        they                 fail
trated                   by        specific                   examples                                drawn                    from              either to          provide                             their                     children                         with               proper                        food
nutritional                         or infectious                                  disease.                                                                 substitutes.
                                                                                                                                                                   Another                        aspect                         of          the             time              distribution             of
                          CHANGES                      IN        DISEASE                       WITH               TIME
                                                                                                                                                            disease                is periodic                                     occurrence.                                   For        example,
        In      1900               the         death                   rate             from                diarrheal                      disease          we      are              accustomed                                       to     the                      fact             that     in                      the
in       children                    under                  one              year               of age                  in       New             York United                    States                       type                 A influenza                             has         a periodicity
City               was             4,496                per               100,000.                                In          1920              it       was
                                                                                                                                                           of       about                two                to         three                    years               and          type               B         of        not
still           1 796                and               in           1961                  it         was               only           45.                  less
                                                                                                                                                          For            than                     four                     to          six          years.                           Epidemics                             of
children                      one          to          four              years                  of          age           this         changed              measles        occur          about                                                    every                  two                years                   and
from               471)            per           100,000                        in             1901               to          120          in          1920poliomyelitis             generally                                                      reaches                      a          peak                   each
and             only               2.4           in         1961.                         Obviously,                                many                 en-year     in the     late       summec.                                                             Nutritional                           diseases
vironmental                                and              host                factors                       are             involved                     in
                                                                                                                                                            also    are  often       periodic.                                                      Pellagra                      appears                      when
this            dramatic                          decline,                          but                the              rates              in          New the         population                                becomes                           depleted                      of         niacin                 as      a
York               City             as         recently                        as         the           early                  1900’s                were result             of the                    gradual                        exhaustion                           of food                 supplies
worse                     than                  in            technically                                     underdeveloped                                during              a long                       winter                        or       dry             season.                    The                 peak
areas               today.                                                                                                                                  is       reached                            just                     before                      the               new             crops                      are
        For              somewhat                             the              same                    reason ‘mehlnar-
                                                                                                                   ‘                                        harvested,                            at             a         time                 when                  exposure                          to          sun-
schaden”                            or          “starch                         dystrophy,”                       which         was      light       as                                       a         result                        of           working                       in           the              fields,
exceedingly         common                                             in Europe      at                               the beginning     contributes                                              to             the               exacerbation                           of          the           skin
of the      century       and                                           which    came                                    from    feeding lesions.
too           much                  carbohydrate                                        and             too              little  protein     In some                                              countries                                kwashiorkor                                has            demon-
to           infants,                    has               disappeared.                           Now                     mehinar-                          strated        a distinct          periodicity          usually      following,
schaden                       is    recognized                                as        nothing                        more           than               theby     a few weeks,            the peak         frequency          of diarrheal
severe      protein                                    malnutrition                                          of          kwashiorkor.                       disease        which        serves       as a precipitating                factor.
The    best     example                                   of the                         virtual                       disappearance                        Like     other       infections,         diarrheal         disease      causes                                                                                 a
of a nutritional                                      disease                      from                the           UnitedStates                           loss       of      appetite,                               and             there                 is a tendency                               toward
is       pellagra,                       which                    in          the              early                    claimed
                                                                                                                    1930’s                                  ingestion                     of            a more                         liquid                   and             more               deficient
thousands                           of         victims                    in        the           South                   and          today                diet;
                                                                                                                                                             is              the          metabolic                                   loss         of        nitrogen                       is increased
almost                   unheard                      of in that                           region.                                                          and        sometimes                                     the          absorption                              of     nitrogen                          from
        Unfortunately,                                  the                    trend                    is              not           always                the         gastrointestinal                                         tract              is         decreased.                                Pur-
                                                                                       Ecological                             Factors                      in          Nutritional                                     Disease                                                                               115


gatives                     are             often                administered                       to       get         rid             of      the            being               lower                    in           equatorial                                 areas               than                 in       those
worms                   which                       are          believed                       to         be         responsible                            closer
                                                                                                                                                           for                       to          the              poles.
the       condition.                                      With                  all         these           factors                     operating                      The            fact               that                   the                distribution                    of          endemic
in      the            same                  direction,                           the          close              relationship                             be-goiter                 is          also               influenced                                  by            goitrogenic                                  sub-
tween                       kwashiorkor                                      and                diarrheal                           disease                     is
                                                                                                                                                                stances                   in      the             diet,            hardness                            of         water                and            water
hardly                      surprising.                              For              the           same               reasons,                      in- polution,         and                                      that                the               incidence                             is      currently
creases                     in         the           occurrence                              of kwashiorkor                                      follow being      reduced                                        by            such                 factors                       as      less               monoto-
epidemics                              of       measles                           and              other              common                           com- nous                    diets,                   importation                             of              food                from                   non-
municable                               diseases.                                                                                                               goitrous                       areas                   and               prophylactic                        iodization                               of
                                                                                                                                                                salt           only                 strengthens                              the               argument                                for            the

                       VARIATION                           OF             DISEASE              WITH                PLACE
                                                                                                                                                                importance                              of         all          three                types                   of        environmental
                                                                                                                                                                factors              -physical,                                   biological                               and           social-in                               the
      The               distribution                                       of          hookworm                               disease                 and causation                             of nutritional                                      disease.
ascariasis                          is obviously                                  closely                  related                  to         climate       Today                             most   of the                                 classic       deficiency                                        diseases
and             soil             conditions                               which                will          support                          embryo-           are          sharply                    differentiated                                          in          place              distribution
nation     of eggs.                                              Where                      the      soil              is frozen                        hard    bythe    degree                                of          social,                  economic                             and            technical




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or nonexistent,                                           as      in the                     Arctic,                  or is dry                       sand, development.                                          In              order                    to               understand                       this
as        in                the               desert,                       the               propagation                of              these                  distribution,                                little               is     contributed                                     from                knowing
diseases                          is          manifestly                                    impossible.                  But                  one               that          beriberi                    is due                   to         a lack                  of      thiamin,                         pellagra
must                  beware                        of         judging                       the           macroclimate                   and                   to     a             niacin-tryptophan                                               deficiency                                or         xero-
forgetting                              the              microenvironment                                   in         which                    the             phthalmia                    to inadequate                                               intakes                          of         vitamin                       A
individual                                  actually                            lives.                                                                          unless                we            know                        the            environmental                             and                 host
  A few years                                       ago          surveys                      in Greenland                                 showed               factors               which                       account                          for          the           actual                   precipita-
a high frequency                                                 of certain                      intestinal                              parasites              tion           of         these                diseases.
which                   are             considered                                    to      be           primarily                           tropical           Admittedly,                                       a clinician                                treating     a patient                                          in
and              subtropical                                    in          their              distribution                  and              not               a hospital                         may               be satisfied                                   to know    only                                        that
able            to          survive                       in         the          Arctic.                        The           answer                   was administration                                            of        a specific                           nutrient                         will           result
simple.                            The                microclimate                           within                    the              houses                  in      cure              of       a given                         clinical                      syndrome,                               but               even
was             hot              and            humid                       and               transmission                                 occurred             this           is          deceptive.                             Under                         the               conditions                                in
as         if           in              the               tropics.                             It           is         pertinent                             which
                                                                                                                                                           that                           nutritional                           deficiencies                                            occur                    in              the
nineteenth                                    century                            pictures                        of           East                    Coast population,                            they                     are rarely       single.
Eskimo                             households                                     in           Greenland                                  show                 all When                        pellagra                      was              common                              in       the           southern
family                      members                             wholly                      unclothed.                                                          United                     States,                         treatment                                   with                niacin                      alone
       The              classic                      example                           of      place               distribution                                of
                                                                                                                                                                sometimes                           precipitated                                     signs                        of                 beriberi.
a nutritional                                   disease                     is endemic                             goiter.                       In        theLikewise,                          treatment                              of beriberi                               or      ariboflavino-
wake              of         the             last              Ice         Age,              vast           and              diverse                   areas sis              with                 thiamin                               or               riboflavin                                  alone                      fre-
of       the                world                    were                  left             iodine-poor.                                      Mature,           quently                    resulted                        in          the          development                                       of signs                    of
iodine-rich                              soil              was              swept                   away                and               replaced              clinical                  pellagra.                               Treatment                                  of         xerophthalmia
by       new                       soil    created                               by              the               grinding                           up    with
                                                                                                                                                             of        only                       vitamin                          A          is still                  likely                  to       limit                   the
crystalline                          rock,    the                          iodine              content                 of which                         was resistance                             and                    growth                          of           the              child                 suffering
only            about                    one-tenth                              the          average                   of mature                        soil. from              protein                       deficiency.                                       Conversely,                                  giving                    a
As        the               great               glaciers                        receded,                     iodine                     replenish-              skim           milk               supplement                                   alone                   to        protein-deficient
ment              of          the             soil             began                  by       iodine                 liberated                        from children                           whose                   diets                 are           also              low          in           vitamin                         A
the        sea              into              the            b
                                                           air y           oxidation                        and              carried                  by        has          contributed                                   to          widespread                                  precipitation                of
air          currents,                               a          process                       which                   has               now             been xerophthalmia.
going                  on               for               some                    10,000                    to          20,000                        years.
                                                                                                                                                                                VARIATION                             OF          DISEASE                      WITH                PERSON
Today                   areas                  in         which                   the          incidence                           of         endemic
goiter                 is         intense                       can             be          reciprocally                                correlated                     In       1817               the              case                fatality                       from                scarlet                     fever
with              the                  length                        of         the           postglacial                                period                in
                                                                                                                                                               of       Richmond,                                  Virginia,                         ranged                         from                 10           to          12
iodine                  replenishment,                                      the              prevalence                             usually                     per          cent              whereas                       in         1962                   there              were                essentially
116                                                                                                                                       Scrimshaw

no       deaths                     from                this            disease.                              In         1960,                  the         lastneeds           are           relatively                           greatest                    in        the             infant               and
year             for          which                   comparable                                    figures                     were                  avail- preschool                        child,                as         well             as      during                     the           pubertal
able,                  the                mortality                                 rate                  from                   measles                       growth
                                                                                                                                                                in                        spurt                     and                   during                     pregnancy                                   and
Mexico                    was             90         times                   higher                  and              in         Guatemala                     lactation.                          All        the         nutrients                         contained                          in breast
189        times                  higher                than                 that             in        the         United                      States.        milk           must            be         ingested                       by       the         mother                      in addition
Measles                      is           a          highly                         communicable                                disease                        to       her          usual               requirements.                                Even               the              lack           of
affecting                           nearly                       all              children                            early                     in             teeth
                                                                                                                                                            life.               at     a very       young      and    frequently                                                                     also           at
Death                  from               measles                      is exceedingly                                          rare             among          old     age           may     be of nutritional          significance.
well           nourished                             children            ,     even                 without                         the              use             Both             environmental        and     host        factors                                                                  are
of       sulfonamides                             and               antibiotics,                                   and           the             viru-         involved                      in        the           highly                     characteristic                   age             dis-
lence             of         the          measles                      virus                 does              not             differ             in       the tribution                     of        many                    nutritional                            disorders.                              The
three             countries.                               Young                        children                      in        Guatemala                      age         specificity                       of weanling                              diarrhea                      has          already
and            Mexico                      are          simply                         more               susceptible                                 hosts. been               described.                        Infantile                            beriberi                         occurs                in
The            malnutrition                           which                    is       responsible                                 for          their         breast-fed                         infants                     at        two             to          three                 months                     of
greatly                       retarded                              growth                              and                   development                      age          because                    this          is            when               the           meager                     stores               of
during                  the          critical                    period                    between                         weaning                         and thiamin                    present                    at            birth              in       a      child                  born             of         a




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school                    age,                also               reduces                            their                  resistance                          deficient
                                                                                                                                                               to                             mother                           become                         exhausted                                 if         the
infectious                           diseases.                                                                                                mother’s                                   milk       is                        deficient                   in thiamin.                                    Iron
        Earlier                   in this               discussion,                               reference                         was  made deficiency                                    anemia                              in      a              child         not                        receiving
to       Santa                    Catarina,                       a rural                      village                   in      Guatemala    proper                                  supplementary                                feeding                   usually                           begins
in       which                     the           nutrition                              of          the             preschool                            child after           six         months                        of        age,              since           innate                     stores               of
has        been               improved                           by          daily            dietary                    supplements.                          iron          last         longer               than                those               of        thiamin.                          Rickets
Although                            two              epidemics                               of         measles                       have                 now is       most              frequently                               seen              during                 the                period                  of
struck                 this               village,                  there                    has           not             been                 a single most                       active                    growth                         because                      vitamin                            D            is
fatality                      in           children                           receiving                              the              additional               needed                 primarily                          for           bone             enlargement.                         Even
food            regularly                        even               though                         no         additional                              medi- in          marked                    vitamin                          D       deficiency                       it          is doubtful
cal        care              has              been               rendered                            and                 the              mortality            whether                    classic                 rickets                    can            develop                      when                such
from             measles                       has          remained                               high             in         surrounding                     factors               as       protein                    deficiency                          prevent                     the         growth
villages.                          Since              the              feeding                      program                         was               intro- of   the child.
duced,                      the         children                        in               Santa                  Catarina                                have    Frequent                             pregnancies                                     may            he         a         major                host
also           had             shorter,       less                  severe                 and                somewhat                                less factor        in                        malnutrition                            in          women                        of           child-
frequent                          episodes                        of           diarrhea                            than                   before               bearing
                                                                                                                                                               or                      age.                  When                   the          demands                         of          pregnancy
than              still            occur              in         surrounding                                    villages                                       and          lactation                       are          not           met            by       diet,               the          mother’s
                                                                                                                                                               own              tissues                     become                           depleted.                             If          the            post-
              HOST                 FACTORS                     IN            NUTRITIONAL                        DISEASE
                                                                                                                                                               partum                  diet            is      not             sufficient                      to        allow                 repletion,
        I will               now              return                   to         the             triad           agent the
                                                                                                                      of        mother
                                                                                                                                host,      becomes         progressively           more      poorly
and            environmental                                factors                     which    are    responsi-        nourished.           This     also       reflects       on     the      early
ble        for          the           variation                          of         disease     with     time,     place health      of successive        offspring.
and               person.                         Although                               I wish      to    emphasize         In a study       in rural      India       a direct     correlation
environmental                                        factors                      in         this             presentation,                              wehas   been      found      between          the     number     of pre-
cannot                        interpret                             adequately                       the                 effects                    of     vious   pregnancies         and     survival         of the  infant.4
either                 environmental                                         or         agent      factors                                in       nutri- In some      parts     of India     there      is also an increased
tional                  disease                       without                            recognizing                                      the         host incidence        of osteomalacia                                                            in      women                         who             have
factors                   with                which                 they                 interact.                                                         had     repeated      pregnancies.’                                                               A        similar                   relation-
        The             effects                  of         age               and                 sex           are             best              under- ship       to iron    deficiency                                                  anemia                    is seen                   in nearly
stood                  in           terms                   of          the                physiological                      changes                          all         lesser          developed                               areas.
with              which                       they             are                associated.                                    In          general,
                                                                                                                                                                                                     PATHOLOGIC                                  STATES
the           faster                the          rate             of         growth                       and            development,
the        higher                   the          nutritional                                 requirements                     per         unit                        In       a person                      whose                     food            supply                  is apparently
of         body                    weight.                             This                  means                       that                nutrient          ample,                 malnutrition                                     can             occur              as             a       result                of
                                                                             Ecological                               Factors                          in      Nutritional                      Disease                                                                             117


noninfectious                                pathologic                            states                    in          the              host.          to        say          nothing                         of      the           administration                                of         medi-
Some                 of          these,                   such              as         congenital                              metabolic                 cines            which                   alter               gastrointestinal                       motility                and
disorders,                    are               not   of immediate           environmental                                                               flora.
origin     ;               others                  with    an     environmental        corn-                                                                 It is not       surprising,                                                therefore,         that                           an      in-
ponent,                    such                 as cancer     and      heart       disease,                                                           arefectious    episode          is an                                           almost       invariable                               ante-
beyond                    the          scope               of      this           discussion.                 Infectious                                 cedent    to kwashiorkor.                                                    Kwashiorkor              can                          be
diseases,                  however,         are     host    factors           which thought            of as                                                                                                    a      frequent                     result             of         synergism
clearly               have    their  origin     in the environment              and of      malnutrition                                                                                                        and            infection                      in        which                   the
which                 have      a profound         effect   on      nutritional     symptoms              of                                                                                                malnutrition                      predominate.                               In
status.                     The               effect              on         nutrition                        is         particularly                    weanling                          diarrhea                          there             is         also          a         synergism
important                       in       technically                             underdeveloped                             areas                        of         malnutrition                                and            infection                      in        which                    the
in which                        a high                    incidence                      of         infections                       occurs symptoms                                            of         the            infection                       predominate.                   It
in        populations                                 which                      are           already                         relatively   is doubtful,                                               however,                        whether                      either                disease
poorly                    nourished.                                                                                                                     would                 be          of        public                  health             importance                           without
       Large                    increases                        in          the              urinary                       output                        of
                                                                                                                                                         the        presence                          of        both               factors.
nitrogen                    have                  been                demonstrated                                  in         bacterial                     Avitaminosis                                   A is also                   closely               associated         with




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diseases                        such                 as          typhoid                        fever,                    pneumonia                      the      stress                         of         infection.                         In              most      infections
and            acute                    febrile                  tuberculosis,                   viral                  diseases                         vitamin                      A           blood                  levels               are            considerably                              re-
such      as              measles                     and           chickenpox,                                   and            systemic                duced                 and    in certain                                   pathological                           states,                   in-
protozoan                    diseases                          such     as malaria.                                                                      eluding                 pneumonia,                                    obstructive                          jaundice                      and
       For            example,                            in          metabolic                           studies,                     it             haschronic                    nephritis,                          the           vitamin                    may              appear                  in
been            impossible                                to      maintain                          nitrogen                         balance             the                                          Moreover,                             giardiasis                      and               other
in      patients                      with             such             acute               diseases                      as        typhoid              intestinal                             parasites                            may                  impair                   intestinal
fever               and               febrile                   tuberculosis                              despite                     greatly            absorption                               of                vitamin                                  As             early               as
increased                        protein                   intake.6’3                    In         the            only              such                   1892          Spicer”                          in          England                      reported                  that               xero-
study                of          a      rickettsial                          disease                   in         man,                Harrell            phthalmia                               frequently                            developed                        in           children
and            co-workers14                                     found                  that               over                 4       gm.               with
                                                                                                                                                          of         meningitis,                                        infantile               diarrhea,                                chronic
protein                   per             kg.             of      body                 weight                     was              required              tuberculosis,                                  measles,                        whooping                            cough              and
to      maintain                         nitrogen                      balance                  during                    the         febrile severe         chickenpox.     Measles                                                                      and     other        in-
period               of         Rocky                     Mountain                            spotted                    fever.               fections        are recognized       to be                                                                  a major       factor     in
       Not           only               do        severe                infections                          increase                   nitro- the      occurrence        of xerophthalmia                                                                         and      kerato-
gen           losses,                   but               INCAP                         studies                     have                  shown malacia                             in          Indonesia,                           where                large             numbers                     of
that                infections                             resulting                        from         vaccination                                     children                 become                            partially                 or         totally              blind      as                 a
against                     smallpox                              and                     administration        of                                       result,              and     more                          sporadically                         in Latin               America,
the                 new                 live-virus                               measles                           vaccine                            also
                                                                                                                                                         Africa                and               Southeast                           Asia.
increase                        the              urinary                         excretion                          of             nitrogen.                   As        to      thiamin                            deficiency,                     the          observations                           of
This            is         also               true              for          immunization                         with               the                 many                 qualified                     observers                         interned                  in         Japanese
17-D            strain                  of        yellow                fever               vaccine                      which                pro- prisoner                          of          war                camps               in      World                  War leave
                                                                                                                                                                                                                                                                        II

duces               almost                   no        febrile               or         systemic                        reaction.                  no doubt                            that                dysentery                      will            precipitate                     acute,
      There                is no                longer                 any             doubt                 that              all         infec- clinical                           beriberi                    in                  persons                  whose                      diet                is
tions           cause                  some               increased                      nitrogen                         loss         in   the chronically                                     deficient                     in       thiamin.2#{176}                 Pneumonia,
urine,              and               that            some              of         them                decrease                      protein malaria                                and           even                 bed           bugs           have            been            listed              as
absorption                            from             the            gastrointestinal                       tract.                        It         factors         capable                                of precipitating                                      acute             beriberi
would                be          a       mistake,                      however,                         to         assume                        that in      persons         in                            a borderline                                  state              of       thiamin
these                metabolic                             effects                  of          infection                           account                                           21

for          all,          or           even                   most,               of          their                influence                           on The                 association                              of         infection                  with            decreased
nutritional                           status.                         As            already                         mentioned,                           blood            levels                  and               increased                   urinary                 excretion                      of
infections                        are           accompanied                        by           a         tendency                              to       vitamin                    C           and             with           clinical                   scurvy              is     well              es-
reduce                 the              intake                   of         solid              food                and               to              sub-tablished.                              An             interesting                         paper              by          Hess22                in
stitute               watery                      gruels               of        lower               protein                       content,              1917             called                      attention                        to          the           frequency                        with
118                                                                                                                                   Scrimshaw


which                 florid              scurvy                    developed                              in        children                     from sometimes                            eliminated                        experimentally                                       by          high
low         income                        families                       in          New                   York                City                after protein                      intakes,        but                  more      often                        protein                  intake
they             had    contracted                                         a febrile                             illness               such               as
                                                                                                                                                           is      drastically                                reduced                     under        these                           circum-
otitis,           pneumonia                                   or         nephritis.                               Even                vaccina-             stances            because                             of          poor            appetite                          and          poor
tion             against                        smallpox                           has                been                reported                        to
                                                                                                                                                           dietary         therapy.
precipitate                           scurvy                       in        malnourished                         children,23
                                                                                                                                                                                            INFLUENCE                    OF        ENVIRONMENT
and         recent                    INCAP                         studies                     have                 demonstrated
an        increased                            excretion                        of         ascorbic                       acid               in       the          Medical                    schools               have                great              difficulty                 in        con-
urine             at          the          height                   of        the          primary                           vaccination                  veying                  to         their            students                   an       adequate                      apprecia-
reaction.                                                                                                                                                   tion          of      the          significance                        of     environmental                    factors
       Of        the              several                    ways               in         which                       infections                      in-in        the          causation                      of disease.                           The           specific                agent
fluence                 iron              metabolism                                 and              the            occurrence                           of a disease
                                                                                                                                                           of                                     is usually               identified                       by      the         physician
anemia,                        blood                   loss             is         the           most                    direct.                      Thewith   the  help   of the laboratory,            and     the host          is
modern                   studies                       carried                     out           by              Roche                 and         co-available        to him     for interview          and     study,         but
workers24               25‘in Venezuela                                             using    Cr-    and                                     Fe”-      the environment           from        which     the patient           comes
tagged              hemoglobin        have                                         shown     that   each                                     hook- may          be  largely    unknown.             An oral      description




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worm             causes      a daily    loss                                       of approximately                                            0.03 of environmental                factors       may     mean         little      to
ml.         of         blood                    or          2.74             ml.           of         blood                   per            million the                 physician                        attending                       a      patient                   who             comes
eggs          excreted.                                Of           persons                      in         a          hyperendemic                       from                 a socioeconomic                                     group               with               which                 he         is
area          10 to               20 per                cent             will            have               an         egg       excretion                unfamiliar.                                  Yet              frequently                          the           key              to         the
equivalent                           to        infection                      with              at         least             100           worms,         nature                  and             occurrence                       of     the          disease               lies          in        the
and           for             a      single                   human                       host                  to        have                500         patient’s
                                                                                                                                                           or                                  environment.                              Without                           personal
more             worms                     is         not           uncommon.                         If         the          diets            of         knowledge                               of     the        environment,                                   this          key             may
persons                   with     severe       hookworm                                                               infection         are not     be                               available                    to       the           physician.                            Adequate
low in                 iron,    typical      iron    deficiency                                                            will almost knowledge                                                  of      an        environment                       is      not           usually
certainly                    be    observed.           Another                                                               interesting     obtained,                                        however,                     without                         firsthand                    experi-
example                        is         the               effect              of          the                 fish           tapeworm,                  ence.
Diphyllobolhrium                                        latum,       which        can                                      produce                                 Environmental                               factors                  are           particularly                 sig-
macrocytic                           anemia                    in man     because                                        of its special                   nificant                    in      the        causation                      of nutritional                             diseases.
avidity                  for           vitamin       B12.26”7                                                                                             Moreover,                             nutritional                     diseases                      are       most                    corn-
    Chronic                         infection       may       decrease     iron-binding                                                                   mon       in                      technically                       underdeveloped                         areas                 in
capacity,                         reduce       iron   retention        and    shorten                                                                 the which                       the            environmental                        circumstances                                    are
life span    of erythrocytes.                                                  At the same                                time,      the                  most                 obscure                   to        western                      and           western-trained
bone    marrow      in persons                                                  with  chronic                                infections                     physicians.                             By            environment                          it         should                    be
may              be           unable                   to          increase                     red              cell          production                 clear                that            the        term             includes                    not          only            physical
sufficiently                              to          compensate                                     for             these                 factors.         and            biological                       factors,                  but       social                       factors                    as
The         result                   is the             so-called                        anemia                        of infection.”                       well.              In the                     case       of             nutritional                           disease,                    the
       Burns,                       fractures,                               accidental                                and                 surgical         environmental                                factors                   may                act           in        at            least
trauma                  also              result               in        strongly                      negative                        nitrogen      three       different        ways                                         :      (1)                  by    affecting                      the
balance                   for             prolonged                            periods                      of         time.                  These availability           of nutrients,                                                (2)                 by   affecting                     nu-
stresses,                     like             that            of         infection,                            result                in      an     tritional
                                                                                                                                                    in-              requirements                                                  of the                  host,     and                   (3) by
creased                  adrenal                       glucocorticoid                                       secretion                        which affecting                                the          intake               of         nutrients.
mobilizes                         nitrogen                     from                muscle                       and           other               rela-            The            environmental                                    factors                   influencing                             the
tively             dispensible           tissues      for                                                  use          by            the        liver availability               of nutrients                                                        are          obviously         of
and              other         essential         organs.                                                               Part                 of         major
                                                                                                                                                    this            significance,       but    almost                                                        entirely        beyond
mobilized                    nitrogen                               spills      over                            into           the            urine. the control              of the  physician.                                                             Included          among
Direct                  necrosis      at                           the     site     of                          the          lesions                  alsothe    environmental                                          factors       affecting         the                            availa-
contributes                            to the                 protein                    loss          and              in the              case          bility
                                                                                                                                                         of          of nutrients                                       are     physical        factors                               such     as
burns                 may             be         very               large.                  The                  negative                     nitro- soil and climate                                         which           directly                     influence                 agricul-
gen         balance                        of          trauma                       can              be          minimized                         and tural  production,                                                  biological                             factors                       which
                                                                                            Ecological                                    Factors                     in       Nutritional              Disease                                                                              119


influence                         the                 types                 of        plants                 and             animals          which there                               are   reports    of studies                                                in rats  in which
the land    can                                       support,                       and                 social                factors.          The three                             times     as much      thaimin                                              per gram    of food
latter   exert                                         their                     effect                   through                      knowledge     was                             required         to prevent                                              increased     pyruvate
of       good                 agricultural                                  practice                        and                its             applica-                 excretion                  in         the          urine             at         35#{176}c.
                                                                                                                                                                                                                                                                compared                                  with
tion          ;          availability                                  of              agricultural                            extension                                   13#{176}c. Also,                   it       has            been               reported                    that             avita-
services                      and                      credit                    ;           political                       and                    economic            minosis              A          can          be          induced                  more               rapidly                 in      rats
stability                     ;             freedoni                             from                    civil         in a hot environment.2’
                                                                                                                          disturbance                   or
war;                  governmental                                          regulations          and        policies;     The     effect      of low                                                                             environmental                            temperatures
land                distribution                                    and        tenure     ;   facilities           for is greatly          reduced                                                                                by     protective                         clothing                        and
food              storage                             and            processing         ; and        adequacy          heated
                                                                                                                       of             buildings.                                                                                     On      the                    other         hand,                       the
food                distribution.                                                                                                                                       necessity                 of       performing                             work             in        heavy,                 clumsy
       The               second                             category                            of        environmental                                            fac- clothing                 may                significantly                              increase                   caloric                 re-
tors,               those                         influencing                                      the             nutrient                             require-        quirements.                           Thus,                   persons                    working                     out             of
ments                 of          the                 host,                 are            most              likely                   to         be          under- doors                  under                    conditions                           of       extreme                      cold               re-
stood                    by                   the                   physician.                                     Again,                            physical,          quire         more               calories                     and         hence                more              thiamin                  as
biological                         and                     social                aspects                    of      the              environment                        well.              As environmental                temperatures          become




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are           all          involved.                                                                                                                                    colder,             there    is also      an increase           in the   urinary
       At           high                     environmental                                      temperatures                                   there                    excretion               of N-methylnicotinarnide.”                 In addi-
is       an          increased                                     loss               of         water                   and                    significant             tion,        water                requirements                                  may             be         increased                     by
quantities                                  of                   essential                               nutrients                                  through             performance                            of         heavy               muscular                        activity                    while
perspiration                            .                  Excessive                                 sodi          am                      chloride                     wearing               clothing                       which                 is         heavier               than             neces-
losses              in            sweat                           must                     be            replaced                           or          muscle          sary        and          which                 subsequently                               leads             to      excessive
cramps                        will                     develop.                                  The               relatively                                 higher sweat
                                                                                                                                                                     loss.      It    is paradoxical         that     excessive
incidence                               of                 iron                  deficiency                             anemia                        thesweating
                                                                                                                                                         in                may      occur     at      either    high     or     low
tropics              I1UIY          in part    be due to excessive                                                                        iron losses    environmental          temperatures.
in            sweat.                   Copper,       manganese,                                                                            phosphorus       Sunshine        and    humidity       also play     a role in the
and           potassium                                     are           also              present                     in       at            least           trace adverse                 effects                 of      high            environmental                                  tempera-
quantities                                  in         sweat,                        and              from               5           to          15          mg.       tures.
                                                                                                                                                                        of                On                  the     other      hand,                                 beneficial                  effects
calcium                    ler                    hour may                    be lost,    depending                                                     upon           are          derived                      from       exposure                                    of     the              skin       to
the               circumstances.                                            Iodine     concentration                                                        in         sufficient                sunshine                        to        prevent                the          occurrence                         of
sweat                 appears                            to vary                                directly                        with                    that    vitamin
                                                                                                                                                                in              D deficiency.                                                     In      areas              in     which                 there
blood                 plasma                           ; thus    it                             is not                       likely                    to    be wasa       wintertime                                            shortage                         of           sunlight                      and
significant                                 factor                          in               the                 development                            of      protective          clothing                                      further                 reduced                    exposure                     of
endemic                                                                                                                                                                 the       skin        to         sunlight,                         rickets    was     common                                      until
   The                   amount                             of         nitrogen                             lost               in              sweat                 is the       advent                of vitamin                            D concentrates.
sufficient                         to         influence                          nitrogen    balance                                                   experi-      As                to      the              biological                         factors                 influencing                        nu-
ments                 and                    may      be                     one     of a number                                                of      factors trient                 requirements                                   of     the          host,              the         occurrence
contributing                                          to         the             high                prevalence                                of      protein         of pathogens                           in the             environment,                                which            through
malnutrition                                     or         kwashiorkor                                     in       tropical                           areas.         infection                 of       the             host             increase                 nutrient                  require-
Conditions                                       need                  not                 be         extreme                             to           produce         ments,                is           particularly                                   important                           and                 has
significant                                      nitrogen                               loss.                       At                an               ambient         already      been                       discussed.
temperature                                       of90#{176}F. in                    New              Orleans,                       an         output                     Examples                           of social                       or          cultural                    factors                    in-
of       75          irig. of                     nitrogen                             per            hour                in          sweat                   was fluencing                        host              requirements                       can         also            be       cited.
observed                      in              moderately                                        active                   young                                   Persons
                                                                                                                                                       men.3#{176}                               who                 acquire                      nutritional             macrocytic
Under      such                                conditions                                    from     2.2 to 2.6 gm.               anemia
                                                                                                                                  of           because   of infection        with                                                                                            fish         tapeworm
total  amino                                  acids     would                                be lost.        However          this would     not be in this      predicament                                                                                                 if it were                      not
loss decreases                                  with lower                                   dietary     protein     intakes.      for their      custom   of consuming                                                                                                  raw     fish.                     Iron
       Water-soluble                                              vitamin                        losses                 also        occur      but, deficiency       anemia      would                                                                  not       be          as      common                        if
in general,                                  they     are                            too      small                  to          be of signifi- everyone            wore    shoes      in                                                              areas            in         which              hook-
cance       in                              practical                                 nutrition.                                 Nevertheless,      worm       is endemic.




                                                                                                                                                                                                                                                                                    I
120                                                                                                                Scrimshaw

       Dietary            habits       which                        result       in                 the         consump-            government                      policies                may                 be          powerful                       factors
tion        of        foods      containing                             significant                             quantities          in      either            increasing                     or         reducing                   the           prevalence
of          goitrogens                         increase                  iodine                      requirements.                  of      malnutrition.
Another                 example                     which           falls              into           this         category                Improved                     availability                        of         food            is        significant
is      the         occurrence                       of      rickets                   in         children                   whose only           to      the              extent                that            it        leads            to            increased
parents                 protect                     them            from                    the           sun           to      keepfood      consumption.                            The    cultural                          factors               which
their          skin            from           turning              darker.                         This          is not          un-influence          food                         consumption                                 are              often                  the
common                         among                    West                 Indian                         Negroes                 decisive
                                                                                                                                    in                    ones.               I\Ialnutrition                               very    often                     results
Panama        and                         the     Canal    Zone    and      has    recently                                         from             dietary                 habits         based                          on   ignorance                          and
been   described                            also     in the Dominican           Republic.                                       food     prejudice.                                     From         a nutritional          point     of
   The    physical,                            biological     and    cultural       factors                                     view    many        beliefs                              regarding        food      are irrational
affecting                the            consumption             of                      food           by          the     host even     when        there                              is a rationalization              for them
can      also            be           readily       identified.                                     Food            patterns in      the       culture.                                    Nutrition           education           is so
in       either                hot           tropical              or        cold                  arctic           climates        difficult            because                    it involves                       not          only              supplying
tend           to       be different     from                                    those                in temperate                  knowledge                  where                      there      is               none,            but                also         dis-
zones.               Altitude  per se has little                                   direct               effect but                  placing              deepseated                         beliefs.




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does       influence                          the    type                   of      food       immediately                                 Sometimes                       food            prejudices                         have               a         rational
available.             As                     to biological                          influences,          it                     hasbasis.              For         example,                in some                        technically       under-
already           been                       emphasized                           that       the    effect                          developed
                                                                                                                                    of                              areas               cow’s    milk                          is considered                                  a
infectious                     diseases                 in      decreasing                            appetite                  and potential                 cause               of       diarrhea                    in      young                      children.
influencing         the                      character        of                 the          diet           is probably             This      belief               arises             from      the                 poor       quality       of milk
more      important                            to nutritional                               states             than    to         itsavailable                 in      many                technically                         underdeveloped
direct              metabolic                       effects.                                                                        areas             due    to adulteration,                                         contamination                                    and
       By     far      the most                      significant                    group                 of environ-               lack             of   refrigeration.                            Under                  such     circum-
mental                factors                influencing                     food             consumption                          is
                                                                                                                                    stances                   reluctance                           to           accept                    even                    recon-
socioeconomic.                                The            relatively                           high           cost           of stituted                   dried               milk             becomes                         understandable
the          so-called         protective                           foods      is a major            factor especially           when        its     use    is likely         to coincide
in          the        appearance                             of       malnutrition               in       anywith     episodes           of infectious          diarrhea        of other
population                       the United
                                ; in                                      States       such    costs      areorigin.      The       original       basis    for avoiding          pork    is
particularly                   conducive                                 to       malnutrition    in          not    hard      to understand.            We     know        now    that
retired                persons        living                            on       limited        incomes. pork         which       is insufficiently          cooked       is a potential
In         technically        underdeveloped                                                 areas               there              source             of sometimes       fatal      trichinosis                                                 and     of            the
is     little        hope  of     improving                                                    the             nutritional          pork             tapeworm,      Tinea       solim,      which,                                                unlike
status         of the people       unless    the                                             price            of suitable           that        of       beef,              can           give           rise          to       hydatid                       disease
food            can             somehow                      be         brought                          within          their through                   autoinfection                             with    fertile     ova.
economic                       reach.                   Although                        free                distribution           In the                 United       States,                        food     faddism                                is a coin-
of food              may             be      an      effective               temporary                           measure,           mon          cause                of      malnutrition.                           At       best              the             so-
it is not acceptable                                    as     a permanent                                  solution.               called             “health”       foods     are   needlessly                                                expensive
   Economic         factors                                    are    closely                                related               to
                                                                                                                                    sources              of nutrients       and     at worst                                              nutritionally
political         ones.                             For     example,                                subsidies                   andimbalanced                           and               irrational.                              Excessive                           con-
price     controls                        may          make     it easier                             for people
                                                                                                      of some          of them    to    to the exclusion
                                                                                                                                   sumption                              of a
buy           food         ;        duties            and          special                    taxes    diet     may
                                                                                                                 may         beraise balanced
                                                                                                                                    dangerous.                  Although
food      costs.           Legislation           requiring          the     enrich- the     diets        consumed               by      the        lacto-ovo           vege-
ment      of cereals          and other        staple      foods      can insure tarians           are         usually             excellent,               eventually
essential         nutrients           even     when        changes        in food the       strict        vegetarians               are       likely         to     have      a
habits         are      difficult         to    achieve.            Systems         of
                                                                                    megaloblastic             anemia             due        to        vitamin            B12
food      rationing            or food       disposal         plans      imposed deficiency.                Diet       fads,       especially             some       of the
by       governments                         represent                  a        direct                  attempt                to reducing                    diets,               are           likely               to       lead                 to          serious
influence                      an        individual’s                            food                 consumption.                  nutritional                        deficiency.                          Unfortunately,    even
Depending                           upon       their               wisdom                         and     objectives,               physicians                        are       guilty                     of    recommending     or




                I
                                                                                      Ecological                               Factors                       in          Nutritional                                 Disease                                                                                 121

approving                                  reducing                              diets                  which                        are            nutri- lower                         socioeconomic                               groups                               in             technically
tionally                  unsound.                                                                                                                             underdeveloped                                      countries                             the               expenditure                             of
       Outright                            food              quackery                            is     particularly                                likely part                 of          the              family                income                                by             the              father                       on
to        victimize                                   elderly                    persons                           living                  on         fixed cheap                     liquor                  leaves               insufficient                                    money                       to         feed
incomes.                           Although                                     nutritional                         deficiencies                               his           family.                          Alcoholic                     beverages                                    also                 displace
are        the          usual                     result,                   quackery,                          food                 faddism                   or
                                                                                                                                                              more                  nourishing                             foods               in          his             own                diet.
ignorance                              occasionally                                    result                 in             excessive                     in-          It    should                    be          clear            that                 the              social                  factors                       in-
takes              of             a          nutrient.                      A             number                        of       cases                of       fluencing                          food     habits                              and                food    consumption
toxicity                 from                     excessively                               large            doses      of vitamin                             are equalled                           in significance                                          only    by the primary
A and                   vitamin                         D have                                been             reported        in the
                                                                                                                                    availability                                                         of          food.                     In               the                 developed                                  and
United                   States.                               As       in            other                  aspects                   of           thera- underdeveloped                                           countries                             alike      ,         educational,
peutics       (and                               of      human      society),                                           the dangerous     anthropological,                                                          religious,                           economic,                                 adminis-
misconception                                          that    “the    more                                    of         a good    thing trative        and                                                 political                   factors                           all            influence                              the
the         better”                              is         hard                 to             eliminate.                                 Cases               of
                                                                                                                                                              adequacy                            of          the           nutrient                            intake                        of             the           mdi-
carotenernia                                  have               been                 reported                          fiom           excessive              vidual                     subject.
consumption                                  of             carrots,                        and               in             Costa                  Rica




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                                                                                                                                                                                                                    CONCLUSION
carotenemia                                      has            been                 seen              in       a        child               who             re-
ceived              excessive                               quantities        of African                                             palm             oil.       The     causes      of the     diseases                                                                       of       man      can                                 be
    In             technically                                   underdeveloped        areas                                                  the             understood        only    in terms       of                                                           his             relationship                                     to
tendency                           of             mothers                            to          withhold                            solid            food his               environment.                                   The             agent                             of          nutritional
from   the    children        at                                            the     onset     of diarrhea                                              and disease                          is         the            relative                           lack                    of           an              essential
to substitute          watery                                                 gruels      and    starchy                                             solu- nutrient,                         but             the          etiology                   of the                     disease                      includes
tions            is,         as            already                     noted,                     a major                       factor                con- host               factors                   which                  determine                                  whether                            or          not              a
tributing                     to             the            high             incidence                             of        kwashiorkor.                  given                     nutrient                        intake                    will                 be              adequate,                                  and
Unfortunately,                                          this       practice                       is often       encouraged       environmental             factors   which      affect       both                                                                                                                      agent
and     followed                                  by           otherwise                          well     trained         physi- and     host.
cians            and,                      for           this           reason,                     is doubly            hard      to The       environment          includes          biological                                                                                                                          and
combat.                            Of             course,                       it         is     not     the      physician’s    social      as well       as physical       factors.            All                                                                                                                    three
intent             that                 the             child           be            maintained                               on          a watery           influence                          the          availability                                of         nutrients,                                the              re-
inadequate                        diet                    for many          weeks,      but       this                                                 is quirements
                                                                                                                                                            a                                           of          the         host                 for                 specific                       nutrients,
common                       result,                     since   protein        malnutrition                                                           can and     the                      consumption                                of nutrients.                                           Determin-
perpetuate                       the                    diarrhea      after      the    infection                                                      has ing     the                       cause      of                     a        nutritional                                        disease       is                               a
passed.                      Physicians                                in        this             country                      who              recom-        study                 in       human                    ecology-of                                     the                interaction                                  of
mend               withholding           solid                                              food  during                              diarrheal               host,             agent                  and            environment.
episodes                are    fortunate                                                  in that      their                            patients
                                                                                                                                                                                                         ACKNOWLEDGMENT
are     well               nourished                                   at             the          start              and                  that          the
                                                                                                                                                                    This            paper          is the             outcome                  of         innumerable                               discussions
episodes                  are short.                                   It            has          been              known                   for      fifty
                                                                                                                                                              with       Dr.              John           E.          Gordon
                                                                                                                                                                                                                          of                             Harvard                    University                                 and
years             that                     the           absorption                               of         nitrogen                        and             fat
                                                                                                                                                              represents                    the        application of much                               of his                philosophy                          and
increases                              quantitatively                                     with                intake                         even             experience            with                 the epidemiology                                 of        infectious                          disease
though                  it         is            less           efficient                        in         diarrheal                        disease.         to        the understanding                           of nutritional                              disease.

Clinically                             a         patient’s                           recovery                           is     better                 with                                                           REFERENCES
adequate                          feeding                        even                     though                    the              volume                   of
                                                                                                                                                                   1.     GORDON,                 J. E.,           CHITKARA,                        I.         D.         and            WYON,          J.     B.
his       stools                  is        increased.
                                                                                                                                                                         Weanling                             diarrhea.              Am.                  J.         M.               Sc., 245:              345,
      A discussion                                     of       the          social                   factors                  influencing                               1963.
food         consumption                                    would                    not         be         complete                         with-                 2. SABIN,    A.                 B.              Cause           and          control             of         fatal,           infantile

out     mentioning                                       the problem                                  of alcohol.         Many                                               diarrheal                       diseases.                   In:               Health                       and             Nutrition,

countries          have                                   a problem                                   with     alcoholics      in                                            vol.         6, p.         54.           United               States                    Papers                   prepared                         for
                                                                                                                                                                             the          United    Nations                              Conference                              on the Applica-
whom       serious                                          multiple                            vitamin                         deficiencies
                                                                                                                                                                             tion         of Science and                       Technology                           for        the Benefit  of
and  cirrhosis                                     of        the     liver                        develop                        because                      of             the          Less          Developed                      Areas.                            Washington,               D.         C.,
inadequate                             food                    consumption.                                   Among                           the                            1963.                U. S. Government                                   Printing                         Office.
122                                                                                                                                                         Scrimshaw

 3.   BABBOTT,                       F.          L. ,          JR.      ,        FRYE,             W.            W.             and            Goimox,                                17.   CHESNEY,                     J.        and           MCCORD,                       A.          B.                    Vitamin                            A          of
         J      .   E.          Intestinal                             parasites                        of man                   in         Arctic                 Green-                      serum                    following                          administration                        of              haliver                      oil in
           land.                Am.                  J.         Trop.                Med.                &        Hyg., 10:             185,                 1961.                             normal                         children                          and             in              chronic steatorrhea.
 4.   India-Harvard-Ludhiana                                                             Population                                  Study.                             Un-                    Proc.              Soc.             Exper.                  Biol.          &         .lIed.,13:             887,                 1934.
           published                           data.                                                                                                                                  18.   KATSAMPES,                          C.        P.     ,    MCCORD,                         A.          B.              and      PI1ILLIP5,

 5.   SNAPPER,                   I.            and          NATHAN,                         D.     J.        Rickets                    and                 osteo-                             W. A.                    Vitamin                        A absorption                              test                 in cases                      of giar-
           malacia.                        Am.                 J.      Med.,          22: 939,                    1957.                                                                        diasis.              Am.                  J.      Dis.            Child., 67:                   189,              1944.
  6   COLEMAN,
           rimetry.
                                      W.
                                                VI.
                                                     and             GEPHART,
                                                                    Notes                the
                                                                                         on
                                                                                                     F.
                                                                                                    absorption
                                                                                                                 C.             Clinical
                                                                                                                                             of
                                                                                                                                                            cab-
                                                                                                                                                        fat and
                                                                                                                                                                                      19.    SPICER,                     H.                    Keratomalacia                         in           young                               children.
                                                                                                                                                                                               Lancet,                  2: 1387,                     1892.
           protein                        in    typhoid                           fever.             Arch.                 mt.          Med.,                  15:                    20.    SMITH,               D.          A.         and WOODRUFF,                          M.              F.          A.                  Deficiency
         882,              1915.                                                                                                                                                                  Diseases                      in            Japanese                      Prison                          Camps.                                  Medical
 7.   COLEMAN,                             W.                  and                DuBois,                        E.            F.             Clinical                        caIn-               Research                      Council                      (London)                             Special                              Report                        Se-
           rimetry.                            vu.                  Calorimetric                                 observation                                  on          the                  ries          No.              274.                    London,                        1951.                            His                   Majesty’s
           metabolism                                  of           typhoid                      patients                   with              and              without                         Stationery                            Office.
           food.                Arch.                mt.             Med.,              15:        887,           1915.                                                               21.   PLATT,                B. S.                  Protein                    malnutrition                          and                   infection.
 8.   SHAFFER,                   P.             A.         and               COLEMAN,                   W.             Protein                         metab-                                  Am.           J.          Trop.                  Med., 6: 773,                   1957.
           olism                in         typhoid                           fever.          Arch.               mt.           Med.,               4:        538,                     22.   HESS,           A.          F.              Infantile                     scurvy.                             v.            A             study
                                                                                                                                                                                                                                                                                                                                         of        its
           1909.                                                                                                                                                                               pathogenesis.                                   Am.           J.         Dis.              Child.,                 14:           337-353,
 9.   KRAUSS,                   E.               Untersuchungen                                         #{252}ber en
                                                                                                                d                      minimalen                                                  1917.




                                                                                                                                                                                                                                                                                                                                                                           Downloaded from www.ajcn.org by guest on October 31, 2011
           Eiweissverbrauch                                                  des Menschen                                        unter                  gesunden                      23.   STERN,           R.                Uber                  den        Zusammen                              Nang OI1
                                                                                                                                                                                                                                                                                                         V                      Skorbut
           und    krankhaften                                                Bedingungen.                              Deutsches                            Arch.                              und          Infektion.                           Ztschr.                Kinderhk.,                        36:         32,             1923.
           KIm.      Med., 150:                                      13,          1926.                                                                                               24.   ROCHE,                M.            and            PEREZ-GIMENEZ,                                        M.               E.                Intesti-
10.   MCCANN,                        W.               S.            The             protein                      requirement                           in      tu-                             nal          loss              and               reabsorption                   of          iron                  in             hookworm
           bercubosis.                           A rch.                mt.          Med.,            29 : 33,                   1922.                                                          infection.                       J. Lab.                     &                      54:49,
                                                                                                                                                                                                                                                                      Ciisz. .lIed.,                                                   1959.
11.   NARASINGA                                RAO, B.                  S.        and        GOPALAN,                       C.          Nutrition                                     25.   ROCHE,               M.,           PEREZ-GIMENEZ,                                   M.              E.    ,     LAYRISSE,                              M.
           and             tuberculosis.                                    H.         Studies    on                           nitrogen,                           cal-                        and           DIPRIsco,                           E.             Study                 of             urinary                            and               fecal
           cium              and               phosphorus                              metabolism                                    in tuberculosis.                                          excretion                           of          radioactive               chromium                                Cr’              in         man.
           Indian                    J.         ill.            Res., 46:             93, 1958.                                                                                                   Its      use          in     the             measurement                                of         intestinal                              blood                  loss
12.   JOHNSTON,                       J.        A.                  Nutritional                           Studies                     in          Adolescent                                   associated                               with               hookworm                              infection.                      J.           Clin.
           Girls                     and                       Their                     Relation                               to            Tuberculosis.                                    Invest., 36:                          1183,             1957.
           Springfield,                                   Ill., 1953.                        Charles                       C         Thomas.                                          26.   VON         BONSDORFF,                              B.           Pernicious                           anemia                              caused                   by
13.   Co            Tm,              KUO,                      N.       H.          and
                                                                                      SCHMIDT,                        L.             The               protein                                 Diphyllobothrium                                     lalum in the     light                                            of          recent                     in-
           status                in            pulmonary                                  tuberculosis.                        A m.               J.          Clin.                            vestigations.                                  Blood, 3 : 91 , 1948.
           Nutrition,                   2: 252, 1954.                                                                                                                                 27.    VON          BONSDORFF,                             B. Diphvilobothriun                                                       latussi            as         a
14.   HARRELL,                       G.   T. , WOLFF,                                        W. A.           ,    VENNING,                             W.           L.                         cause               of         pernicious                          anemia.            Exper.                        Parasitol.,                      5:
           and             REINHART,                            J.          B.           Prevention                              and              control                     of               207,              1956.
           disturbances                                   of          protein                       metabolism                                     in              Rocky              28.   CARTWRIGHT,                              G. E.                 and        WINTROBE,                                ltd.             M.                 The
           Mountain                              spotted                          fever ;     value              of        forced                  feedings                                    anemia                   of infection                            xvii.                 A review.                                        In      :         Recent
           of            high-protein                                diet             and               of            administration                               of                          Advances                             in          Internal                    Medicine,                     vol.             5,          p.          165.
           specific                   antiserum.                                 South.             M.           J., 39 : 551,                          1946.                                     Edited                 by          Dock,                  W.,          and              Snapper,                                I.               Chicago,
15.   GANDRA,                  Y. R.                        and                  SCRIMSHAW,                                N.          S.               Infection                                 1952.                 Year              Book  Publishers,                                           Inc.
           and              nutritional                               status.                             mm.    Effect f mild
                                                                                                                      o                                                            29.      MITCHELL,                    H.              H. and EDMAN,      M.                                                 Nutrition                             and
           virus            infection                           induced       by                        17-D yellow      fever vac-                                                            Climatic                       Stress.                      Springfield,                              Ill.                  1951.                    Charles
           cine            on         nitrogen                    metabolism                            in       children.                        A m.              J.                         C Thomas.
           Clin.             Nutrition,                         9:          159,            1961.                                                                                  30.       BOST,    R.                      W.              and BORGSTROM,                              P.                Cutaneous                                    ex-
16.   GOLDSMITH,                           G.          A.              Nutritional                               Diagnosis.                                   Spring-                          cretion                   of        nitrogenous                              material                             in             New                Orleans.
           field,           III.,              1963.                   Charles                     C
                                                                                                  Thomas.                                                                                      Am.           J.         Physiol.,                79:         242,         1927.

				
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