Describe the methods of nutritional assessment and surveillance.

Methods of Nutritional Assessment

• Anthropometry is the most widely used method, being objective, cheap, non-invasive, requiring simple equipment and little training, and giving a record of past as well as present nutrition
• Weight — the most sensitive measure of current nutritional status, since it changes rapidly
• Height or length — reflecting long-term nutrition, changing slowly; measured lying (length) under 2 years and standing above, a detail that matters since the two differ by about a centimetre
• The derived indices — weight-for-age (underweight), height-for-age (stunting) and weight-for-height (wasting), each expressed as a Z score against the WHO growth standards
• Mid-upper arm circumference (MUAC) — measured at the mid-point between acromion and olecranon on the left arm, hanging relaxed; its great advantages are that it needs only a tape, requires no age, and changes little between 1 and 5 years
• The colour-coded SHAKIR tape allows an illiterate worker to classify a child: green above 13.5 cm is normal; yellow 12.5 to 13.5 is moderate malnutrition; red below 12.5 (and below 11.5 for severe acute malnutrition) requires action
• Head and chest circumference — the chest normally overtakes the head at about 6 to 9 months, so a head circumference still exceeding the chest at 2 or 3 years suggests malnutrition; this is a useful field indicator needing no age
• Skinfold thickness at the triceps and subscapular sites, measuring subcutaneous fat; and waist circumference and BMI for over-nutrition
• The growth chart (Road to Health card, now the Mother and Child Protection Card) is the practical tool
• Its key principle is that the direction of the curve matters more than the position on it — a child growing steadily along a lower line is doing better than one who has flattened or fallen away from a higher line
• A flat or falling line is the danger sign and calls for action, whatever the absolute weight; and the chart serves as an educational and motivational tool for the mother as much as a record
• Biochemical assessment — haemoglobin, the most useful single test; serum protein and albumin; serum retinol; urinary iodine; serum ferritin and iron studies; and urinary nitrogen and creatinine excretion
• It detects subclinical deficiency before clinical signs appear, which is its main value, but is expensive, invasive and needs a laboratory
• Clinical examination — looking for signs in the hair, eyes, mouth, tongue, skin, nails, thyroid and skeleton
• Its limitation is that clinical signs are late, non-specific and subject to observer variation, and appear only when deficiency is well advanced
• Dietary assessment — the 24-hour recall, which is quick and simple but depends on memory and may not represent usual intake; the food frequency questionnaire; weighment of raw or cooked food, the most accurate but laborious; and the food inventory or expenditure method for households
• Ecological and indirect indicators — vital statistics such as infant and under-five mortality, and the age-specific mortality in 1 to 4 year olds, which is particularly sensitive to malnutrition; food balance sheets; socio-economic and agricultural data; and health service statistics

Nutritional Surveillance and Indian Data

• Nutritional surveillance is the continuous monitoring of the nutritional status of a population for the purpose of action — the same "information for action" principle that governs disease surveillance
• Its three objectives — to describe the nutritional status of the population, particularly of vulnerable groups, and identify determinants; to provide information for policy and planning and to predict trends; and to monitor and evaluate nutrition programmes
• The vulnerable groups to be monitored — infants and children under 5; adolescent girls; pregnant and lactating women; and the elderly
• The reason for concentrating on these groups is that they have proportionately higher requirements relative to body size, and are the first to show the effects of a household food deficit — so they act as sentinels for the whole community
• The sources of nutritional data in INDIA:
• The national family health survey (NFHS) — the principal source, providing anthropometry, anaemia, breastfeeding and complementary feeding indicators, district by district, which allows targeting
• The comprehensive national nutrition survey (CNNS), which added biochemical data on micronutrient status that surveys had previously lacked
• The national nutrition monitoring bureau (NNMB), which conducted repeated diet and nutrition surveys over decades, providing India’s trend data
• The ICDS and POSHAN tracker, giving real-time growth monitoring data from Anganwadi centres
• The Sample Registration System, the Census, and agricultural and food balance data
• The key indicators reported — prevalence of stunting, wasting and underweight in under-fives; low birth weight rate; anaemia prevalence in children, women and adolescents; exclusive breastfeeding and complementary feeding rates; and BMI distribution in adults, now including overweight
• The picture these data give of India — stunting and underweight have declined steadily but remain high; wasting has been more stubborn; anaemia remains very high and has proved resistant to programme effort; and overweight and obesity are rising in every state
• Wide inter-state and inter-district variation is the dominant feature, which is exactly why district-level data matter more than national averages for planning
• The limitations to acknowledge — surveys are periodic rather than continuous, so they detect change late; measurement error in field anthropometry, particularly of height and age; haemoglobin estimation by capillary sampling overestimates anaemia compared with venous sampling, which has been a live methodological debate in India; recall bias in dietary methods; and data collected for reporting rather than for use
• The principle that should conclude the answer — surveillance is only justified if it leads to action; growth monitoring without growth promotion — weighing children and recording it without counselling, referral or feeding — is a waste of the worker’s time and the family’s
• Direction matters more than position on a growth chart, so a flat or falling line is the danger sign
• Growth monitoring without promotion is wasted; weighing without counselling or referral helps nobody
• Remember ABCD for assessment — anthropometry, biochemical, clinical and dietary, with ecological as a fifth
• Weight reflects current and height past nutrition, which is why both are measured rather than one
• Measure length lying under two years and height standing above, since the two differ by about a centimetre
• MUAC needs no age and no scales, which makes it the field tool of choice for community screening
• The Shakir tape lets an illiterate worker classify a child by colour alone, which is its practical genius
• Chest overtakes head at six to nine months, so a head still larger at two years suggests malnutrition
• Biochemical tests detect subclinical deficiency before any clinical sign appears, which is their main value
• Clinical signs are late and non-specific, and appear only when deficiency is well advanced
• Twenty-four hour recall is quick but memory-dependent, and may not represent usual intake
• Weighment is most accurate and most laborious, which is the trade-off in every dietary method
• One to four year mortality is nutrition-sensitive, and is a useful indirect indicator of community nutrition
• Vulnerable groups act as sentinels, showing a household food deficit before anyone else does
• NFHS gives district-level data, which is what allows targeting rather than uniform national programmes
• CNNS added biochemical micronutrient data that earlier surveys lacked entirely
• Capillary sampling overestimates anaemia compared with venous, which has been a live methodological debate in India
• Wasting has proved more stubborn than stunting, which is an uncomfortable finding worth stating
• Anaemia has resisted programme effort, remaining high despite decades of supplementation
• Overweight is rising in every state, alongside persisting undernutrition, which is the double burden in data
• Inter-district variation exceeds the national average in importance, which is the argument for local planning
• Surveys are periodic and detect change late, which is the inherent limitation of survey-based surveillance
• Height and age are the error-prone measurements in field anthropometry, and deserve the most training