Adding 200 ml of milk or milk products (including curd), an egg or 45 grams of legume (dal) to the daily diet can reduce the risk of stunting in children younger than two years, researchers at St. John’s Medical College, Bengaluru found. The risk of stunting in children aged one-three years reduces by 10% when egg and milk are consumed along with cereal and pulse combination.

About 38% of children in India below the age of five years are stunted. One of the reasons for this is that the food consumed by young children are mainly cereal based, which lack quality protein that can be well digested and are limited in its content of certain essential amino acids such as lysine. Using a novel, non-invasive technique, researchers at St. John’s Medical College, Bengaluru measured the digestibility and quality of commonly used complementary foods in young children. They found that mung bean, which is a legume and is considered to be a high-quality protein source, is not as well digested and absorbed as other high quality food proteins such as egg. The quality of protein is an important part of a young child’s diet.

They found that the risk of stunting in children aged one-three years (in the NFHS-4 survey) was reduced by 10% when high quality proteins such as egg and milk were consumed along with cereal and pulse combination. This food-based reduction of risk can be achieved by adding 200 ml of milk or milk products (including curd), an egg or 45 grams of legume (dal) to the daily diet of the child. If these foods are added to the diet of children aged less than two years, the risk of protein inadequacy reduces to 7% for egg, 8% for milk and 11% for legumes (dal).

Of the 20 amino acids that humans need, the body cannot synthesise nine. Dietary protein is the only source of the nine essential amino acids.

Stunting happens early

“Stunting happens early before children turn three years. While consuming quality protein that contains adequate amounts of digestible essential amino acids does help in reducing the risk of stunting, it cannot completely prevent it. Several other factors including genetics, poverty and sanitation play a role,” says Prof. Anura V. Kurpad from the institute’s Department of Physiology and senior author of a paper published in the American Journal of Clinical Nutrition. Prof. Kurpad is a Margdarshi Fellow of the Wellcome-DBT India Alliance.

“Young children’s diet between the age of 1-3 years should contain a minimum of 100 grams of cereal (rice or wheat) and 45 grams of legume per day. Unfortunately, this is not followed in a consistent way anywhere in India,” he says. “The equivalent will be the addition of an egg or 200 ml of milk or milk products to the diet every day, which makes it expensive for many people.”

Four complementary foods studied

The researchers measured the essential amino acid digestion of four — rice, finger millet, mung dal and egg — commonly consumed complementary food by children aged below two years. While digestibility of essential amino acids was least for mung dal (65%), it was highest for egg (87%). It was 78.5% and 68% for rice and finger millet, respectively.

“We choose these four food items as they are the most common complementary food given to babies after six months of exclusive breast feeding. Ragi (finger millet) is the main complementary food after six months, and legume (mung dal) and rice are given when the baby aged nine-twelve months,” says Dr. Nirupama Shivakumar from St. John’s Medical College and first author of the paper.

Though the digestibility of essential amino acids in the case of rice (78.5%) comes quite close to egg (87%), rice (and other cereals) has a lower concentration of lysine, an essential amino acid, and consequently, does not contain high-quality protein.

The digestibility of essential amino acids contained in the four food items was measured by labelling them with a stable isotope of hydrogen (deuterium). Chicken were fed with labelled amino acids so they produced labelled eggs. Similarly, water labelled with deuterium was used for growing rice, mung dal and finger millet plants so that they produced labelled seeds.

The method of measuring protein digestibility was developed at St John’s Medical College and is considered by the FAO to be one of the best non-invasive methods to measure protein digestibility and quality in humans.

Published in The Hindu on April 2, 2019