Docstoc

Assessing Nutritional status

Document Sample
Assessing Nutritional status Powered By Docstoc
					Assessing Nutritional status
                       Dr. Shivananda Nayak
                     Faculty of Medical Sciences
                  The University of The West Indies


•The nutritional status of an individual is the result of many
  interrelated factors
• It is influenced by food intake, quality, quantity and physical
  health
• The spectrum of nutritional status spread from obesity to
  malnutrition
                                                                    1
   Why Nutritional assessment required

It is required to:
 Develop health care programs which meet the
  community needs which are defined by the
  assessment
 Measure the effectiveness of the nutritional
  programs and intervention once initiated

Methods of nutritional assessment
It is assessed by direct and indirect methods
                                                2
The direct method
Deal with the individual and measure objective criteria
Summarized as ABCD
 Anthropometric methods
 Biochemical and laboratory methods
 Clinical methods
 Dietary evaluation methods

Indirect methods of nutritional assessments
 Uses community health indices that reflects nutritional
  influences
These include
 Ecological variables including crop production
 Economic factors e.g. per capita income, population density
  and social habits
 Vital health statistics particularly infant under 5 mortality and
  fertility index
                                                                3
Clinical assessment method
    It is an essential feature of all nutritional
     surveys
    Simplest and most practical method of
     ascertaining the nutritional status of a group
     of individuals
    It utilizes a number of physical signs that
     are known to be associated with
     malnutrition & deficiency of vitamins &
     micronutrients

                                                4
 General clinical examinations, with special
  attention to organs, like hair, nails, skin, gums,
  eyes, muscles, tongue, angles of mouth and
  thyroid gland
 Detection of relevant signs helps in
  establishing the nutritional diagnosis

Advantages of Clinical assessment
 Fast and easy to perform
 Inexpensive
 Non-invasive
Limitations
 May not detect the early stages
                                                5
Anthropometric measurements
•Anthropometry is the measurement of body weight
 and proportions
•It is an essential part of clinical examination of
 infants, children and pregnant woman
•It is also used to evaluate both under and over
 nutrition
•The measured values reflect the current nutritional
 status.

                                                       6
Other anthropometric measurements:
 Mid-upper arm circumference
 Head circumference
 Skin fold thickness
 Head/chest ratio
 Hip/waist ratio


Anthropometry for children
Accurate measurement of height and weight is necessary to
evaluate the physical growth of the child
Ht/Age:
 Height of index child compared with the expected weight of
  a healthy child of the same age
 Measure of long term nutritional status or stunting
Wt/Ht:
Measure of wasting ie. Appropriate weight for given height 7
Mid Upper Arm Circumference:
 Measured half-way between the acromion process of
  the scapula and the tip of the elbow (ulnar) with the
  arm hanging vertically and forearm supinated
 Provides an estimate of Arm Muscle Area: reflect
  skeletal protein reserves lean body mass useful in
  monitoring vulnerable groups, especially children

Head Circumference:
 Useful in children under the age of 3 and is an
  indicator of non-nutritional abnormalities. Under
  nutrition must be severe to affect head circumference

                                                     8
Anthropometry for adults
Height measurement
   The subject stands erect and bare footed on a stadiometer
    with a movable head piece is leveled with skull vault and
    height is recorded to the nearest 0.5 cm

Weight measurement
   Use of regularly calibrated electronic or balanced-beam scale
    is suggested to measure the weight.
   During weight measurement wearing light clothes without
    shoes is suggested
   Read to the nearest 100 gm.

Skin folds
 Triceps, Biceps, Sub-scapular, Supra-iliac used in combination
  to obtain body fat
                                                                9
Nutritional Indices in adults
 The international standard for assessing body size in
  adults is the body mass index (BMI)
 BMI is computed using the following formula
BMI =        Weight (kg) kg/m2
             Height (m2)
     <18.5        = Underweight
     18.5-24.9 = Normal Weight
     25-29.9      = Overweight
     30-34.9      = Moderate Obese       (Class 1)
     35-39.9      = Severely Obese       (Class 2)
    40          = Extreme Obesity
                                                    10
BMI = Weight (lbs) x 703
        Height (in2)
<18.5     = Underweight
18.5-24.9 = Normal Weight
25-29.9   = Overweight
30-34.9   = Moderate Obese (Class 1)
35-39.9   = Severely Obese (Class 2)
40       = Extreme Obesity (Class 3)

High BMI (obesity level) is associated with type 2 diabetes and
high risk of cardiovascular morbidity and mortality

Waist/Hip ratio
 Waist circumference is measured at the level of the umbilicus to
  the nearest 0.5 cm
 The subject stands erect with relaxed abdominal muscles, arms
  at the side, and feet together
 The measurement should be taken at the end of a normal
  expiration                                                     11
Waist circumference
 Waist circumference predicts mortality better than
  any other anthropometric measurement
 It has been waist circumference alone can be used to
  assess obesity and two levels of risks have been
  identified
                  Males      Females
  Level 1         >94 cm     >80 cm
  Level 2         >102 cm >88 cm
 Level 1 is the maximum acceptable waist
  circumference irrespective of the adult age and there
  should be no further weight gain
 Level 2 detects the obesity and requires weight
  management to reduce the risk of type 2 diabetes
  and cardiovascular complications                  12
Hip circumference
 It is measured at the point of greatest circumference
  around hips and buttocks to the nearest 0.5 cm
 The subject should be standing and the measurer
  should squat beside him
 Both measurement should be taken with a flexible,
  non-stretchable tape in close contact with the skin,
  but without indenting the soft tissue

Interpretation of Waist/Hip Ratio (WHR)
 High risk WHR = >0.80 for females and >0.95 for
  males i.e. waist measurement > 80% of hip
  measurement for women and 95% for men indicates
  central obesity and is considered high risk for
  diabetes and cardiovascular disorders             13
A WHR below these cut-off levels considered low risk

Advantages of Anthropometry
 Simple, non-invasive.
 Equipment is inexpensive, portable.
 Relatively unskilled personnel can perform
  measurements.
 Methods are reproducible.
 Measures long term nutritional history.
 Quickly identifies mild to moderate malnutrition.
 Measures many variable of nutritional significance
  like height weight, skin fold thickness, head
  circumference waist and hip ratio and BMI        14
Disadvantages of Anthropometry
 Relatively insensitive to short term nutritional status
 Cannot identify specific nutrient deficiencies
 Measurements: e.g.. Skin-folds difficult to carry out in obese
  people
 Ethnic differences in fat deposition


Dietary assessment
 Nutritional intake of humans is assessed by five different
  methods
 24 hour dietary recall
 Food frequency questionnaire
 Dietary history from the beginning
 Food dairy technique
 Observed food consumption


                                                               15
24 hour dietary recall
 A trained interviewer asks the subject to recall all
  food and drink taken in the previous 24 hours
 It is quick, easy, and depends on short term
  memory, but may not be truly representative of the
  person’s usual intake

Food frequency questionnaire
 The subject is given a list of around 100 food items
  to indicate his or her intake (frequency and
  quantity) per day, per week and per month
 It is inexpensive, more representative and easy to
  use
                                                    16
Dietary history
 It is an accurate method for assessing the nutritional
  status
 The information should be collected by a trained
  interviewer
 Details about the usual intake, types, amount,
  frequency and timing needs to be obtained
 Cross-checking to verify data is very important


Food dairy
 Food intake should be recorded by the subject at
  the time of consumption
 The length of the collection period range between 1-
  7 days
 It is reliable but difficult to maintain
                                                     17
Observed food consumption
 The most unused method in clinical practice (must
  for research)
 The meal eaten by the individual is weighed and
  contents are to be calculated exactly
 High degree of accuracy but expensive and needs
  more time and efforts

Interpretation of dietary data
1.Qualitative method
 Using the food pyramid and the basic food groups
  method
 Different nutrients are classified into 5 groups (fats
  and oils, bread and cereals, milk products, meat-fish-
  poultry, vegetables and fruits                    18
Determine the number of serving from each group and
compare it with minimum requirement

2. Quantitative method
 The amount of energy and specific nutrients in each food
   consumed can be calculated using food composition tables
   and then compare it with the recommended daily intake
 Evaluation by this method is expensive and time consuming,
   unless computing facilities are available


Laboratory measurements
 Blood: accessible, relatively non-invasive reflect recent
  dietary intakes but influenced by: diet; drugs; infection;
  stress
                                                               19
   Haemoglobin is the most important test and useful
    index of the overall state of nutrition. Beside anaemia
    it also gives idea about protein and trace element
    nutrition
   Stool examination: to detect the presence of ova and
    intestinal parasites
   Urine examination for albumin, sugar and blood
   RBC vs WBC: gives idea about long/short term
    nutrient status
   Analysais of hair nails and skin for micronutrients
    (Cu, Se, Zn, Hg,etc)
   Detection of abnormal amount of metabolites in the
    urine (creatinine/hydroxyproline ratio)
   Functional tests done to study about the metabolic
    pathways
                                                       20
Advantages of Biochemical Measurements
 It is useful in detecting early changes in body metabolism and
  nutrition before the appearance of overt clinical signs
 It is precise, accurate and reproducible
 Useful to validate data obtained from dietary methods (e.g.
  comparing salt intake with 24- hour urinary excretion

Disadvantages of Biochemical Measurements
 Expensive
 Time consuming
 Needs trained personal and facilities


Reference: Essentials of Biochemistry by
                    Dr S Nayak
                                                            21