Assessing Nutritional status

1. 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

2. 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

3. 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

4. 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

5. 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 ofClinical assessment • Fast and easy to perform • Inexpensive • Non-invasive Limitations • May not detect the early stages

6. 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.

7. 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

8. 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

9. 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

10. 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

11. 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

12. 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

13. 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

14. 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

15. 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

16. 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

17. 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

18. 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

19. 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

20. 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

21. 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