Why protein quality matters
Protein is essential for almost every function in the body. It helps build muscles, repair tissues, support immunity, and produce hormones and enzymes. For children, it is especially important because it plays a key role in growth, brain development, and protection against infections.
How much protein do we need?
How much protein a person needs depends on age, body weight, and stage of life. According to Dr Jain, school-going children generally require around 0.9 to 1.1 grams of protein per kilogram of body weight each day, while adults need about 0.8 to 1 gram per kilogram. The requirement increases during periods of rapid growth, illness, and recovery.
The Indian Council of Medical Research (ICMR) also recommends including good-quality protein from a variety of animal and plant sources as part of a balanced diet, rather than relying on a single food.
More than just grams of protein
Dr Jain stressed that eggs remain the benchmark against which other protein sources are measured because they contain all nine essential amino acids in the right proportions and are highly digestible.
“Soy is probably the only vegetarian protein that comes close because it also contains all nine essential amino acids. Most other plant proteins, including pulses, lentils, beans and cereals, are deficient in one or more essential amino acids and therefore need to be eaten in the right combinations,” he said.
That distinction is important because nutrition experts increasingly argue that protein quality matters as much as quantity. A single egg contains around 6 to 7 grams of protein. However, simply replacing those 6 or 7 grams with a similar amount from another food may not produce the same nutritional outcome.
Scientists use measures such as the Protein Digestibility Corrected Amino Acid Score (PDCAAS) and the newer Digestible Indispensable Amino Acid Score (DIAAS) to assess how effectively the body can digest and use proteins. Eggs consistently rank among the highest on these measures because they provide all essential amino acids in highly digestible forms.
Dr Jain explained that eggs are also rich in leucine, an amino acid that plays a critical role in muscle growth and tissue repair, and lysine, which is often limited in cereal-based diets that many Indians consume. Plant foods also contain naturally occurring compounds such as phytates and fibre that can reduce protein digestibility.
“The problem with Indian nutrition is not only inadequate protein intake but also poor protein quality,” Dr Jain said. “Children may consume enough calories but still miss out on important amino acids needed for healthy growth.”
The question becomes even more important for children who depend on school meals as a major source of daily nutrition.
Eggs offer more than protein
Dr Nishant Tanwar, head of dietetics and nutrition at Yatharth Hospital, Faridabad Sector 88, told Business Standard that eggs offer much more than protein.
“Besides providing around 6 to 7 grams of high-quality protein, an average egg is a natural source of vitamin B12, choline, vitamin D, selenium and highly bioavailable iron, nutrients that are essential for brain development, immunity, and growth,” he said.
Vitamin B12 deficiency is relatively common among people following vegetarian diets because the vitamin is found naturally almost exclusively in animal-derived foods. Similarly, iron from plant foods is absorbed less efficiently by the body than iron from animal foods. Choline, another nutrient important for brain development, can also be difficult to obtain in adequate amounts from vegetarian diets alone.
Can vegetarian foods replace an egg?
“It is quite difficult to obtain an equivalent amount of usable protein from pulses and legumes alone because their proteins are generally less digestible and they contain considerably more carbohydrates than an egg. Also, larger portions are needed to match the protein in an egg,” Dr Tanwar said. “Soy performs much better, while paneer provides similar protein but with substantially higher fat and calorie content.”
Dr Tanwar said the most practical public health approach would be to provide eggs to children who consume them while offering carefully formulated vegetarian alternatives for those who do not. Such alternatives should combine soy, dairy, and other plant foods in ways that match not only the protein content of eggs but also their broader nutritional value.
