Probiotics are they worth taking

Document Sample
Probiotics are they worth taking Powered By Docstoc
					For personal use only. Not to be reproduced without permission of the editor

                                                                                                                                                                                Continuing professional development
 Probiotics: are they worth taking?
 Pamela Mason looks at the evidence for the benefits of ingesting “friendly bacteria”

       robiotics are live cultures of micro-

 P     organisms, usually bacteria, that, when
       ingested, survive passage through the
 upper gastrointestinal tract and have benefi-
 cial effects on the host (see below). The most
 common bacteria used in probiotics include
 Lactobacillus species, bifidobacteria, some
 streptococci and other gram-positive cocci.
 These micro-organisms should resist gastric
 acid, bile salts and pancreatic enzymes, and
 adhere to and readily colonise the bowel
 where they displace potentially dangerous
 bacteria and create an environment that is
 unfavourable for the multiplication of such
     In the UK, probiotics are available in foods
 or food supplements, sometimes sold com-                                                                          Identify knowledge gaps
 bined with prebiotics (see Panel 1), vitamins                                                                     1. Can you list three suggested uses for
 and minerals and digestive enzymes.                                                                                  probiotics and the evidence for these
 However, in Italy, one probiotic product, a                                                                          suggestions?
 suspension of Bacillus subtilis spores manufac-                                                                   2. What are the quality issues for probiotics?
 tured by sanofi-aventis, has been available                                                                       3. What is a prebiotic?
 over the counter since 1999 for the treatment
                                                                                                                   Before reading on, think about how this article may
                                                                                              Christopher Icha

 and prevention of gastrointestinal disorders.
 Increasingly popular, probiotics in the UK are                                                                    help you to do your job better. The Royal
 consumed as fermented dairy products, such                                                                        Pharmaceutical Society’s areas of competence for
 as yogurts and drinks, fruit juices, and                                                                          pharmacists are listed in “Plan and record”,
 dry preparations (ie, tablets, capsules and              Claims on probiotic                                      (available at: This article
 powders).                                                products include helping                                 relates to “appropriate management of common
     Uses suggested for probiotics include:               to support the body’s                                    symptoms” (see appendix 4 of “Plan and record”).
                                                          natural defences
 ■ To reduce the incidence and severity of
   diarrhoea                                                                                                         Over 400 species of bacteria can be found
 ■ To reduce the risk of allergic conditions                                                                     in the human gut. The most common are bac-
 ■ To improve immune function                                                                                    teroides (30 per cent of all gut bacteria),
 ■ To manage inflammatory bowel condi-                                                                           clostridium, fusobacterium, eubacterium, ru-
   tions, such as Crohn’s disease, ulcerative                                                                    minococcus, peptococcus, peptostreptococcus
   colitis and irritable bowel syndrome                                                                          and bifidobacterium. Escherichia and lacto-
 ■ To prevent Helicobacter pylori gastritis                                                                      bacillus are present to a lesser extent. The gut
 ■ To reduce symptoms of lactose intoler-                                                                        microflora aids digestion and some organisms
   ance                                                                                                          produce vitamins and minerals.
 ■ To reduce vaginal infections                                                                                      The normal gut microflora also provides
 ■ To decrease blood cholesterol                                                                                 protection against pathogenic organisms and it
 ■ To protect against bowel cancer                                                                               is thought that probiotics alter the balance of
                                                                                                                 the gut microflora to maximise this effect.This
                                                                                                                 idea is lent credence by the observation that
   Panel 1: Prebiotics                                                                                           breast-fed babies (who have fewer gastroin-
                                                                                                                 testinal and respiratory infections than bottle-
   Prebiotics are non-digestible food substances that promote the growth of beneficial                           fed babies) pass stools in which 99 per cent of
   bacteria in the gastrointestinal tract. Chemically, prebiotics are oligosaccharides and                       the bacteria are bifidobacteria. Breast milk is
   examples include inulin-type fructans, fructooligosacharides and oligofructoses, which                        rich in prebiotics and this may be why growth
   are present in many fruits and vegetables.                                                                    of bifidobacteria is encouraged. In compari-
       Prebiotics resist digestion in the upper part of the gastrointestinal tract and are                       son, the gut microflora in bottle-fed babies is
   fermented by endogenous anaerobic micro-organisms in the colon to produce lactic acid                         much more diverse, with higher levels of bac-
   and short chain carboxylic acids (eg, acetic, butyric and propionic acid). This                               teroides, clostridia and Escherichia Coli.
   fermentation provides metabolic substrates to the cells of the colon, stimulating growth                          The presence of “good bacteria” in the gut
   of the bifidobacteria population.                                                                             could reduce the risk of infection through
       Prebiotics also promote the absorption of calcium and magnesium, and possibly other                       several mechanisms:
   minerals and trace elements within the colon. Evidence is also emerging that they may
   reduce serum lipids, particularly triglycerides. They are also being investigated for a                       ■ They might compete with pathogens for
   possible protective effect in bowel cancer, constipation, inflammatory bowel conditions,                        nutrients and adhesion sites in the gut and
   allergic dermatitis and lactose intolerance.                                                                    so reduce the chances of pathogens
                                                                                                                   colonising the gut                                                                                                                    31 March 2007 The Pharmaceutical Journal (Vol 278) 373
                ■ They secrete antimicrobial substances and                                          in atopic dermatitis.6 Although evidence from
                  produce an acidic environment that in-                                             these clinical trials is not definitive, probiotics
                  hibits the growth and survival of                                                  may be particularly effective for atopy in in-
                  pathogens                                                                          fancy or when given to mothers with a high
                ■ They may break down toxins responsible                                             risk of producing an atopic infant during
                  for adverse effects produced by pathogens                                          pregnancy. Earlier trials indicate that probi-
                ■ They may influence an immune response,                                             otic use leads to a reduction in inflammatory
                  which could enhance ability to fight                                               mediators.
                  infection.                                                                             It is thought that optimising gut flora
                                                                                                     might reduce the risk of allergic disease by
                    Factors that might affect the composition                                        preventing increases in gut permeability asso-
                of gut flora include antibiotic therapy, gas-                                        ciated with infection (and so improving the
                trointestinal disease, poor diet, age and stress.                                    barrier to antigen penetration) or stimulating
                    Probiotics are intended to be taken daily.                                       anti-allergic immunological responses.
                Doses are generally expressed in millions or
                billions of bacteria. Examples of doses used in                                      Immunity
                studies are shown in Panel 2. For how long a                                         Studies have shown that probiotics influence
                probiotic should be taken is unclear. For                                            immune parameters. However, the clinical
                “traveller’s diarrhoea” (diarrhoea associated                                        significance of these results is unknown
                with a change in climate, social conditions or                                       because most of these studies did not have a
                sanitary standards), some products should be                                         clinical end-point.
                started two weeks before departure and con-                                              Three recent RCTs have investigated the
                tinued for one week after return, but in trials,                                     effect of probiotic bacteria on the common
                probiotics have been taken for between two                                           cold.Taking probiotic strains for at least three
                weeks and 12 months.                                                                 months significantly shortened common cold
                                                                                                     episodes and reduced the severity of symp-
                Diarrhoea                                                 Factors that               toms7 and, in conjunction with vitamins and
                Probiotics have been claimed to help prevent
                and treat diarrhoeal disease, including anti-
                                                                       might affect the              minerals, reduced the incidence and severity
                                                                                                     of symptoms in otherwise healthy adults.8
                biotic-associated diarrhoea, traveller’s diar-          composition of               The third trial showed that the intake of a
                rhoea and infectious diarrhoea in adults and                                         probiotic had no effect on the incidence of
                children. Many studies have been conducted             gut flora include             common colds, but shortened duration of
                and several systematic reviews and meta-                                             episodes and severity of symptoms.9
                analyses are now available. One meta-analysis              antibiotic
                (n=4,844) indicated that probiotics reduced
                the risk of antibiotic-associated and traveller’s
                                                                            therapy,                 Inflammatory bowel diseases
                                                                                                     Patients with inflammatory bowel diseases,
                diarrhoea.1 Another large meta-analysis                gastrointestinal              such as Crohn’s disease, ulcerative colitis and
                (n=3,164) showed that probiotics could re-                                           irritable bowel syndrome, may have an ab-
                duce the risk of antibiotic-associated diar-             disease, poor               normal gut microflora in terms of both the
                rhoea, including that caused by Clostridium
                difficile.2 Lactobacilli and Saccharomyces boulardii
                                                                         diet, age and               organisms and their ability to adhere to the
                                                                                                     gut wall. Probiotics can potentially reduce the
                have been identified as having particular ben-               stress                  population of abnormal bacteria and reverse
                efit in this regard.                                                                 any problems of adhesion. Inflammatory
                    Overall, meta-analyses appear to indicate                                        bowel conditions are also associated with ab-
                that probiotics can reduce the risk of acute                                         normalities in gastrointestinal immunity and
                infectious diarrhoea in children and adults.                                         restoration of a healthy flora may help to im-
                There is also some evidence that probiotics                                          prove gut immune function.
                can reduce the duration of diarrhoea if an                                               Evidence of clinical benefit in clinical tri-
                attack occurs — an effect that is most marked                                        als with probiotics in inflammatory bowel
                for diarrhoea associated with human rotavirus,                                       conditions is mixed. For Crohn’s disease the
                a common cause of infant diarrhoea.                                                  outcomes of most RCTs were not significant.
                                                                                                     For example, of five RCTs published be-
                Allergic disease                                                                     tween 2000 and 2006, only one small trial
                Several randomised controlled trials (RCTs)                                          (n=32) showed decreased clinical relapse. For
                have investigated the potential for probiotics                                       ulcerative colitis, however, the evidence is
                to help prevent or treat allergic disease, such                                      predominantly positive. Outcomes have in-
                as eczema. Three recent RCTs looked at the                                           cluded an increase in relapse free time and a
                effect of using probiotics for three months on                                       reduction in inflammation. Furthermore, two
                atopic dermatitis. One trial showed no signif-                                       relatively large trials (n=327 and n=116)
                icant effect,3 but the other two showed an im-                                       showed that E coli Nissle 1917, used for a year,
                provement in the condition. In one trial, the                                        had an equivalent effect to mesalazine in
                improvement was only seen in food-sensitised                                         maintaining remission.10,11 Another RCT
                children4 and in the other trial, a synbiotic (a                                     with 90 patients, showed that taking VSL#3 (a
                combination of a probiotic and a prebiotic)                                          patented combination of eight probiotic
                was used.5 A larger trial on 1,223 pregnant                                          strains, including bifidobacteria and lacto-
                women and their babies (four probiotic                                               bacillus) and low-dose balsalazide for eight
                strains were used by the mothers two to four              Pamela Mason, PhD,         weeks was more effective in achieving remis-
                weeks before delivery and given to babies for             MRPharmS, is a freelance   sion than drugs alone.12
                six months) showed no effect on any allergic              journalist and author,         For irritable bowel syndrome, the evi-
                disease by the age of two years, but a decrease           based in Monmouthshire     dence is hopeful but not conclusive. For ex-

374   The Pharmaceutical Journal (Vol 278) 31 March 2007                                                             
                                                                                                                                                                                    Continuing professional development
                                                                                                                                                                                    Continuing professional development
                                                                                                                        ach. In combination with antibiotics they may
                                                                                                                        increase eradication rates or reduce adverse ef-
                                                                                                                        fects or both.15 A more recent trial in 138 pa-
                                                                                                                        tients found that four-weeks’ pretreatment
                                                                                                                        with lactobacillus and bifidobacterium yogurt
                                                                                                                        can improve the efficacy of quadruple therapy
                                                                                                                        after triple therapy has failed.16

                                                                                                                        Lactose intolerance
                                                                                                                        Lactose intolerance is a problem for a large
                                                                                                                        number of people. If lactose is administered in
                                                                                                                        yogurt containing live bacteria, the lactose is
                                                                                                                        hydrolysed by bacterial lactase. This prediges-
                                                                                                                        tion of lactose could potentially reduce the
                                                                                                                        symptoms associated with lactose intolerance
                                                                                                                        in susceptible individuals, but evidence from
                                                                                                                        clinical trials is mixed.

                                                                                        Scimat/ Science Photo Library
                                                                                                                            A systematic review assessing the efficacy of
                                                                                                                        oral probiotics in adults with lactose intoler-
                                                                                                                        ance found that some probiotics may be effec-
                                                                                                                        tive in alleviating the signs and symptoms of
                                                                                                                        this condition, but further trials of specific
                                                                                                                        strains and concentrations are necessary.17
Lactobacillus species are used in probiotics and have been
identified as reducing the risk of antibiotic-associated diarrhoea                                                      Vaginal infections
                                                                                                                        Probiotics have been claimed to reduce the in-
ample, two RCTs were published in 2006.                                                                                 cidence of vaginal infections, particularly
One indicated that symptoms of IBS de-                                                                                  thrush. Lactic acid bacteria predominate in the
creased with four weeks of 1x108 colony                                                                                 normal flora of the vagina, generating an acid
forming units of Bifidobacterium infantis com-                                                                          pH, which inhibits the growth of other organ-
pared with placebo, but not with higher or                                                                              isms that can cause vaginal infections. A
lower doses.13 The other showed a decrease in                                                                           number of factors, such as pregnancy and dia-
abdominal pain but no significant difference                                                                            betes, can contribute to changes in the vaginal
in other symptoms.14                                                                                                    microflora and cause vaginal infections.
                                                                                                                            There is limited evidence to support
Helicobacter gastritis                                                                                                  the effectiveness of probiotic preparations
Evidence from laboratory and animal trials                                                                              although several studies have shown that oral
suggests that probiotic organisms are effective                                                                         consumption of probiotics can alter vaginal
against H pylori. Clinical trials in humans have                                                                        microflora. The vaginal application of live
been conducted but many have been subject                                                                               yogurt has been recommended as a natural
to limitations such as small numbers of par-                                                                            remedy for thrush but no RCTs have investi-
ticipants and lack of placebo control. In some                                                                          gated the effects of topical application.
cases, probiotics were given along with stan-
dard H pylori eradication therapy with the                                                                              Cholesterol
aim of finding whether the probiotic could                                                                              Probiotics have been evaluated for potential
reduce the side effects of the eradication reg-                                                                         influence on serum cholesterol and other car-
imen rather than the efficacy of the probiotic.                                                                         diovascular risk factors. However, evidence
    A recent systematic review concluded that                                                                           generated from studies so far has been mixed
probiotics do not eradicate H pylori but main-                                                                          and if there is an effect at all, it appears to be
tain lower levels of the pathogen in the stom-                                                                          weak.

                                                                                                                        Bowel cancer
  Panel 2: Examples of doses of probiotics in studies                                                                   Regular, long-term consumption of probiotics
                                                                                                                        has been suggested to protect against bowel
  Condition                       Micro-organism(s)             Daily dose                                              cancer. The basis for this is that the acid pH in
                                                                (number of organisms)                                   the colon generated by probiotics could pre-
                                                                                                                        vent the growth of mutagen-generating bacte-
  Diarrhoea in children           Lactobacillus reuteri         10–100 billion                                          rial species. However, there is no consistent
  Rotavirus diarrhoea             Lactobacillus GG              5–10 billion                                            evidence that probiotics prevent cancer in
  Prevention of diarrhoea         L GG                          12 billion                                              humans.
      in children
  Prevention of antibiotic-       L GG                          20 billion                                              Safety and quality
      associated diarrhoea                                                                                              Side effects that have been recorded with the
  Prevention of atopic allergy    Lactobacilli                  20 billion                                              use of probiotics include abdominal bloating
  Irritable bowel syndrome        B infantis                    1 billion                                               and flatulence. Although probiotics are largely
                                  Lactobacillus plantarum       20 billion                                              safe, it may be wise not to recommend
                                  VSL#3                         450 billion                                             them for people who are severely immuno-
  Ulcerative colitis              Lactobacilli/bifidobacteria   10 billion                                              compromised.
  Helicobacter pylori infection   L acidophilus/B lactis        5 billion                                                   Quality issues for probiotic products
                                                                                                                        include:                                                                                                                         31 March 2007 The Pharmaceutical Journal (Vol 278) 375
                                                                                                                     meta-analysis of masked, randomised, placebo-controlled
               ■ The bacterial content of the prod-
                                                                                                                     trials. The Lancet Infectious Diseases 2006;6:374–82.
                 uct Does the product contain the bacter-                                                        2. McFarland LV. Meta-analysis of probiotics for the prevention
                 ial species on the label ? Does it contain                                                          of antibiotic associated diarrhoea and the treatment of
                 any potentially pathogenic micro-organ-                                                             Clostridium difficile disease. American Journal of
               ■ The viability of bacteria in the
                                                                                     There is                        Gastroenterology 2006;101:812–22.
                                                                                                                 3. Brouwer ML, Wolt-Plompen SA, Dubois AE, van der Heide S,
                 product How many live organisms are                                promising                        Jansen DF, Hoijer MA et al. No effects of probiotics on atopic
                 present at the time of manufacture, the                                                             dermatitis in infancy: a randomized placebo-controlled trial.
                 time of purchase and the time of con-                            evidence that                      Clinical & Experimental Allergy 2006;36:899–906.
                                                                                                                 4. Sistek D, Kelly R, Wickens K, Stanley T, Fitzharris P, Crane J.
                 sumption? Some products make no claim
                 at all, while others claim the amount only
                                                                                probiotics could                     Is the effect of probiotics on atopic dermatitis confined to
                                                                                                                     food sensitised children? Clinical & Experimental Allergy
                 at the time of manufacture. Some prod-                         be beneficial in                     2006;36:629–33.
                 ucts, such as capsules, require the bacteria                                                    5. Passeron T, Lacour JP, Fontas E, Ortonne JP. Prebiotics and
                 to be freeze-dried and such processes may                       the prevention                      synbiotics: two promising approaches for the treatment of
                 also affect viability. A US study conducted
                 by found that among                              of diarrhoea,                      atopic dermatitis in children above 2 years. Allergy
                 26 probiotic products, eight contained less
                 than 1 per cent of the claimed number of
                                                                                   particularly                  6. Kukkonen K, Savilahti E, Haahtela T, Juntunen-Backman K,
                                                                                                                     Korpela R, Poussa T et al. Probiotics and prebiotic galacto-
                 live bacteria or of the claimed minimum                           antibiotic-                       oligosaccharides in the prevention of allergic diseases: a
                                                                                                                     randomized, double-blind, placebo-controlled trial. Journal
                 of 1 billion.
                                                                                   associated                        of Allergy and Clinical Immunology 2007;119:192–8.
                                                                                                                 7. de Vrese M, Winkler P, Rautenberg P, Harder T, Noah C, Laue
                   In addition, there has been debate about
               whether or not probiotic bacteria survive
                                                                                 diarrhoea, and                      C et al. Effect of Lactobacillus gasseri PA 16/8,
                                                                                                                     Bifidobacterium longum SP 07/3, B bifidum MF 20/5 on
               stomach acid and the journey along the gas-                       the prevention                      common cold episodes: a double blind, randomized,
               trointestinal tract. According to a US review,                                                        controlled trial. Clinical Nutrition 2005;24:481–91.
               evidence suggests that the bacteria can survive                      of allergic                  8. Winkler P, de Vrese M, Laue C, Schrezenmeir J. Effect of a
               the gastrointestinal tract with survival rates of                                                     dietary supplement containing probiotic bacteria plus
               20–40 per cent,18 but the same review also                            disease                         vitamins and minerals on common cold infections and
                                                                                                                     cellular immune parameters. International Journal of Clinical
               stated that there is no evidence that orally
                                                                                                                     Pharmacology and Therapeutics 2005;43:318–26.
               administered probiotic organisms adhere to                                                        9. de Vrese M, Winkler P, Rautenberg P, Harder T, Noah C, Laue
               intestinal cells — they seem to pass into the                                                         C et al. Probiotic bacteria reduced duration and severity but
               faeces without adhering or multiplying, sug-                                                          not the incidence of common cold episodes in a double blind,
               gesting that, to produce benefit, the probiotic                                                       randomized, controlled trial. Vaccine 2006;24:6670–4.
               must be administered continually.                                                                 10. Kruis W, Fric P, Pokrotnieks J, Lukas M, Fixa B, Kascak M et
                   Another study, published by the UK Food                                                           al. Maintaining remission of ulcerative colitis with the
               Standards Agency in 2005,19 involving 12                                                              probiotic Escherichia coli Nissle 1917 is as effective as with
               commercial products, found that most well                                                             standard mesalazine. Gut 2004;53:1617–23.
               known products matched their label claims in                                                      11. Rembacken BJ, Snelling AM, Hawkey PM, Chalmers DM, Axon
               quality and content. However, not all the bac-                   Action: practice                     AT. Non-pathogenic Escherichia coli versus mesalazine for
                                                                                                                     the treatment of ulcerative colitis: a randomised trial. The
               terial strains in the products had the ability to
               survive intestinal digestion. Overall the study
                                                                                points                               Lancet 1999;354:635–9.
                                                                                                                 12. Tursi A, Brandimarte G, Giorgetti GM, Forti G, Modeo ME,
               showed that Lactobacillus species are resistant to               Reading is only one way to           Gigliobianco A. Low-dose balsalazide plus a high-potency
               the gastric environment but are sensitive to                     undertake CPD and the                probiotic preparation is more effective than balsalazide
               upper intestinal content, while bifidobacteria                   Society will expect to see           alone or mesalazine in the treatment of acute mild-to-
               are more likely to be affected by gastric juice                  various approaches in a              moderate ulcerative colitis. Medical Science Monitor
               but survive well in the upper intestine. The                     pharmacist’s CPD portfolio.          2004;10:PI126–31.
               researchers warned that this in vitro study of                   1. Discuss with another          13. Whorwell PJ, Altringer L, Morel J, Bond Y, Charbonneau D,
                                                                                                                     O'Mahony L et al. Efficacy of an encapsulated probiotic
               individual strains may not replicate the in vivo                     pharmacist, whether or
                                                                                                                     Bifidobacterium infantis 35624 in women with irritable
               activity of a probiotic product containing                           not you would recommend          bowel syndrome. American Journal of Gastroenterology
               several strains.                                                     a synbiotic.                     2006;101:1581–90.
                                                                                2. Do you stock probiotics?      14. Kim YG, Moon JT, Lee KM, Chon NR, Park H. [The effects of
               Conclusion                                                           How can you assure the           probiotics on symptoms of irritable bowel syndrome]. Korean
               There is promising evidence that probiotics                          product’s quality?               Journal of Gastroenterology 2006;47:413–9.
               could be beneficial in the prevention of                         3. Train your staff on           15. Gotteland M, Brunser O, Cruchet S. Systematic review: are
               diarrhoea, particularly antibiotic-associated                        prebiotics and probiotics.       probiotics useful in controlling gastric colonization by
               diarrhoea, and the prevention of allergic dis-                                                        Helicobacter pylori? Alimentary Pharmacology and
               ease. However, more research is needed to                        Evaluate                             Therapeutics 2006;23:1077–86.
                                                                                                                 16. Sheu BS, Cheng HC, Kao AW, Wang ST, Yang YJ, Yang HB et al.
               clarify findings.                                                For your work to be presented
                                                                                                                     Pretreatment with Lactobacillus and Bifidobacterium-
                  The quality of some products in terms of                      as CPD, you need to evaluate         containing yogurt can improve the efficacy of quadruple
               claimed bacterial content and survival of                        your reading and any other           therapy in eradicating residual Helicobacter pylori infection
               micro-organisms in the intestine has been                        activities. Answer the               after failed triple therapy. American Journal of Clinical
               found wanting. Moreover, many people take                        following questions: What            Nutrition 2006;83:864–9.
               these products for general gastrointestinal                      have you learnt? How has it      17. Levri KM, Ketvertis K, Deramo M, Merenstein JH, D’Amico F.
               health and whether probiotics produce such                       added value to your practice?        Do probiotics reduce adult lactose intolerance? A systematic
               benefits in healthy people is unclear.                           (Have you applied this               review. Journal of Family Practice 2005;54:613–20.
                                                                                learning or had any              18. Bezkorovainy A. Probiotics: determinants of survival and
                                                                                                                     growth in the gut. American Journal of Clinical Nutrition
                                                                                feedback?) What will you do
               References                                                       now and how will this be         19. An evaluation of probiotic effects in the human gut: microbial
               1. Sazawal S, Hiremath G, Dhingra U, Malik P, Deb S, Black RE.   achieved?                            aspects. Food Standards Agency 2005. Available at:
                  Efficacy of probiotics in prevention of acute diarrhoea: a
                                                                                                            (accessed 23 February 2007).

376   The Pharmaceutical Journal (Vol 278) 31 March 2007                                                                                 

Shared By:
Description: Probiotics are they worth taking