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Layperson’s guide to nutrition and malnutrition

By Ramani Atkuri with Jan Swasthya Sahyog

Malnutrition underlies 50% of all under-5 deaths worldwide. What are the links between malnutrition and ill-health? How is malnutrition to be determined and measured?

Most, if not all of us, have been reading the newspapers and watching on TV various observations about the high prevalence of malnutrition in India, especially among the country's children. Books and journal articles talk of stunting, wasting, weight for height measurements, and BMI. But what do all these terms mean? And what do they imply?

Malnutrition is a condition when the body's nutritional status is sub-optimal. Both overnutrition (obesity) and undernutrition are states of malnutrition. However, since the majority of people in India still suffer from undernutrition rather than obesity, this article uses the word malnutrition to refer to undernutrition.

Food is required for every essential function of the body: for energy, growth, protection against infection and the ability to fight illness. This food is obtained and consumed in the form of carbohydrates (energy foods like oils, sugar, rice and wheat), proteins (growth foods like beans, dals, rice, wheat, meat, eggs), vitamins (protective foods available in fruits and several green leafy vegetables, as well as in the outer coating of unpolished rice, sprouted lentils, etc), and minerals (iron in green leafy vegetables and meat, calcium in ragi).

The body requires energy to function -- every organ, be it the intestines, heart or brain, works only if it gets enough glucose to burn. This glucose is obtained from the food we eat. When we eat more than is required, the excess carbohydrate is stored as fat in our body, to be broken down and used whenever we need it. This fat is stored under our skin, in our abdominal wall, the cheeks, buttocks and also around our intestines.

Protein is required for body building and body repair. Many tissues in the body are routinely broken down and replaced by newer tissue. Our blood, the outer layer of skin, etc, are constantly being replaced.

Vitamins are needed for certain vital functions like eyesight, proper functioning of our nervous system, the ability to maintain our bones and skin, for making blood, and for enhancing the capacity of our body to fight infections.

Minerals are required in minute quantities for many essential functions of the body, the most common being the requirement for iron to make blood. Iron deficiency anaemia is a very common illness in Indians. However, haemoglobin (the essential component of blood) requires bothiron and protein for its synthesis, so just giving iron tablets to an undernourished anaemic person will not be enough to improve their anaemia. We must at the same time ensure that they have sufficient protein in their diet to be able to utilise the iron effectively.

Measuring nutritional status

How do we measure whether a person is well-nourished or malnourished? The nutritional status of a person depends on many factors, including whether they are eating enough and whether they are ill or well. Measuring vitamin or protein levels in the body is not easily done, and is expensive. Moreover, such facilities are not available everywhere.

Therefore, we use other means to determine the nutritional status of a person (adult or child) or community. One of the commonest means of doing this is by anthropometry, which is the measurement of size and proportion of various body parts.

The most common measures taken in nutritional anthropometry are height, weight and skin-fold thickness. From these, various indices are calculated. To measure the nutritional status of a population, we need not measure everyone. Measuring a sample is enough. And if we take repeated measures over a period of time, we get information on the growth of the individual or nutritional status of that community.

Weight for age: This is the commonest indicator used in children. Since children grow very fast, their weight changes significantly with age, unlike in adults. By measuring a very large number of children, standards have been developed that give the expected weight for any given age. A child whose weight is less than expected for his/her age is said to be underweight. This may be due to insufficient food or illness, and often signifies food deprivation in the recent past. This indicator requires that the age of the child be known.

A young child being weighed using Salter scales

Height for age: When a child has been undernourished for a long time, her bone growth is also affected. Such a child remains short for her age. Low height for age indicates chronic hunger, and such children are said to be stunted. This indicator requires that the age of the child be known.

Weight for height: This is an age-independent measurement. A child who has been malnourished for a long time will be short and underweight. However, the ratio of her weight for height will be normal, or near-normal. A child whose weight for height is low indicates that she has recently lost weight: her long-term nutrition and bone growth may have been normal or below normal but she has suddenly lost weight. Such a child is said to be 'wasted'. When a malnourished child is given sufficient food to eat (as in a nutritional rehabilitation programme), the weight starts increasing almost immediately, though the height will take much longer to increase. Therefore, the ratio of weight for height will improve dramatically within a week or two.

Body mass index (BMI): Generally, body weight is used as an indicator of an individual's health. This is compared with a desirable weight range to identify whether the individual is underweight or overweight. The body mass index is worked out by dividing the individual's weight in kilograms by height in metres squared. A high value can indicate excess fat while a low value indicates reduced fat. Hence, body mass index correlates the individual's height and weight. It is considered a useful tool in identifying obesity or malnutrition.
BMI value for normal men and women should be within the range of 19 to 27 kg/m2. A BMI between 13 and 15 corresponds to 48-55% of desirable body weight for a given height and is considered the lowest body weight that can sustain life. At this level of BMI, the body fat is less than 5%.

BMI values for different conditions

Condition Men Women
Malnutrition <17 <17
Underweight <20 <19
Acceptable 20.7-27.8 19.1-27.3
Intervention needed >26.4 >25.8
Obese >27.8 >27.3
Severely obese >31.1 >32.2

BMI = Wt in kg/m2 (ht in metres x ht in metres)

The BMI for children varies with each age-group, whereas for adults it is constant across age.

Link between malnutrition and ill-health

I remember my mother and her friends discussing how someone they knew looked 'thin and sick', and how someone else had put on weight and was looking 'healthy'. While I scoffed at this equating of fat with health, there is little doubt that undernourished people -- children or adults -- are more prone to illness and also more severe manifestations and consequences of illness.

Malnutrition in a person reduces their immunity to infection, making them more susceptible. More particularly in children, poor appetite during an illness episode reduces their body weight, further affecting their immune system and making them more prone to continuing or newer infections.

Malnutrition in children increases their risk of death from many diseases, most prominently measles, pneumonia and diarrhoea. That is, a well-nourished child who gets measles will lose some body weight, may also get pneumonia or diarrhoea after measles, but will recover. Children who are already malnourished and get measles will most probably get severe pneumonia or diarrhoea, and their chances of death following measles are many times higher than their well-nourished counterparts. Thus, programmes to prevent malnutrition can significantly reduce death from these diseases.

It has been shown that malnutrition underlies over 50% of all under-5 deaths worldwide.

On average, a child who is severely malnourished is 8.4 times more likely to die due to an infection than a well-nourished child. However, over 80% of deaths attributed to malnutrition occur in children who are mildly to moderately malnourished.

Even in adults, chances of death due to common illnesses like tuberculosis are much higher in malnourished individuals than in well-nourished ones.

Growth monitoring and growth charts

How do we know whether a child's weight is normal or not? We compare her weight with the 'expected' weight for her age. This 'expected' weight has been developed by several groups, by weighing a very large number of healthy children of the same age-group and finding the average (mean) or the median (middle) weight and defining a range of values that are above and below this value as 'normal'. Normally, values within plus and minus 2 standard deviation is considered normal.

If we define the range in percentiles, the median weight would be at the 50th percentile. A value of +2SD corresponds to the 97th percentile, which means that only 3% of children in any sample would weigh more than this, and this is considered outside the normal range. Similarly, children below the 3rd percentile (below -2SD) are considered outside the normal range -- only 3% of normal children would weigh less than this, and so children having this weight would be considered to have a below normal weight. In other words, any child whose weight falls between the 3rd and 97th percentile will be considered to have a normal weight.

The most commonly used growth monitoring tool is the growth curve depicting standard curves for weight for age. This is what is used in the ICDS system in anganwadis. The weight of the child is plotted on the graph each month against her age, and is compared to the standard growth curve. The top curve corresponds to the median (50th percentile). The chart has three colour-coded zones: green depicting normal nutrition (upto -2SD); mild malnutrition (between -2SD and -3SD, yellow), and severe malnutrition (less than -3SD, red).

The chart is shown below, and is different for boys and for girls, following the WHO Child Growth Standards (http://www.who.int/nutrition/publications/severemalnutrition/9789241598163/en/index.html).

The WHO chart only has two lines: the top one depicting the median weight for age (50th percentile), and the lower depicting the 3rd percentile (corresponding also to -2SD). Any child whose weight falls between these two lines is considered to have a normal weight for that age. The curves are different for boys and for girls.

The ICDS growth chart

The growth chart can be used to record the weight of a child at specified intervals to detect any growth faltering at an early stage. It can also be used as a tool to educate parents about their child's growth. The main point to note is that the weight of the child should increase each month, so a growth curve going up is a good sign. A flat graph for two or more months, or a curve going down signifies that the child needs special care and attention.

However, it must be mentioned that a large majority of field workers, including anganwadi workers and supervisors, find it difficult to comprehend the concept of graphs with the two axes, and have difficulty filling it in.

(Dr Ramani Atkuri did her MD in Community Medicine from the Christian Medical College, Vellore. Her area of interest has been maternal and child health in rural areas, and has focused on training village-level and paramedical workers, and traditional birth attendants. She has worked in rural Orissa and Madhya Pradesh and is now with the Jan Swasthya Sahyog in Bilaspur, Chhattisgarh state. Her article is based on the work of the JSS collective)

(Jan Swasthya Sahyog (JSS) is an organisation of health and allied professionals established in 1999 in Bilaspur district of Chhattisgarh. Its objective is to develop and provide a low-cost, effective, community-based model of primary healthcare. JSS runs a community health programme in 53 tribal villages using trained women health workers to raise awareness about significant causes of mortality in the region, and also work on important issues including malnutrition, waterborne diseases and childbirth (www.jssbilaspur.org))

Infochange News & Features, July 2012