04/01/2016 04:29 pm ET | Updated Apr 01, 2016

Have we Been Hooked on Micronutrients in our Search for the Solution to Stunting?

Co-author Richard D. Semba, Johns Hopkins University

Today, some 160 million children under five years of age don't get the food and nutrients that their bodies need for optimal growth and development. One hundred and sixty million children that are likely to remain trapped in a vicious cycle of malnutrition and poverty. No wonder the 'new' Sustainable Development Goals (SDGs) have 'no poverty' and 'zero hunger' as the first and second of the 17 Global Goals. This makes the eradication of malnutrition, with a special focus on children, a top priority for countries as they turn the SDGs into actions.

To support the SDGs, the World Health Assembly has set a target to reduce chronic malnutrition in young children by 40% by the year 2025. So how do we measure chronic malnutrition and what do we do to turn the tide? Children who have a poor overall diet fail to grow tall enough and so end up relatively short for their age - they are termed stunted and suffer from chronic malnutrition. This matters, not only because stunting is an indicator that the diet was inadequate to meet their needs in the critical first 1,000 days from conception to their second birthday, but also because stunted children face a lifetime of disadvantage. Early nutritional deprivation impairs cognitive and motor development and leads to a greater likelihood of illness or death during childhood. And if they survive to adulthood, they have a lower work and earning capacity and are at greater risk of becoming obese.

Over the last four decades, much of the focus in addressing chronic malnutrition was on ensuring that children received sufficient micronutrients - particularly vitamin A, iodine, iron, zinc, and folate. There was the widespread assumption that they were receiving enough protein from their basic diet. So micronutrient malnutrition also known as 'hidden hunger', because vitamin and mineral deficiencies are not often obvious to the eye, has dominated efforts and innovations to improve the nutrition of children under five.

Providing micronutrients in the form of supplements; powders that can easily be sprinkled over porridge and; fortified foods, is the current major strategy to reduce chronic malnutrition. Indeed vitamin A supplementation has saved the sight and lives of millions of children, but it does not improve linear growth. Frustration has been brewing as increasingly the research shows that micronutrient supplements and lipid-based nutrient supplements with micronutrients also have little effect on reducing stunting. It is becoming clear that the lack of improvement in growth, from these much touted interventions, suggests that something fundamental is still missing or inadequate in children's diets in addition to micronutrients.

Potentially important insights going forward have come to light in a paper just published in EBioMedicine. This new research, carried out by scientists at the Johns Hopkins University, the National Institute on Aging, University of Maryland, Washington University in St. Louis, University of Malawi, and the Sight and Life Foundation, analyzed blood samples of over 300 children with and without stunting. The children, aged between one and five years, lived in villages in rural Malawi. Instead of focusing on micronutrients, the research looked at the essential amino acids that are the building blocks of proteins, and must come from the diet.

They are considered 'essential', since the body cannot build bones, muscle, brain, or other tissues unless each and every one of these building blocks, are present in adequate amounts.

The striking finding of the study is that all nine essential amino acids were significantly lower in stunted children compared with non-stunted children. In fact, most of the amino acid levels were as much as 15-20% lower in the stunted children. This is important because it tells us that stunted children are in reality not receiving sufficient quality protein from their diet and this lack of essential amino acids means children will not grow normally even if they receive the necessary micronutrients.

How did protein fall off the international development map? From about 1950 to the mid-1970s, there was great concern that the lack of protein was a grave threat to the health of young children in developing countries. This galvanized actions, such as strengthening animal and fishery resources, to address what was called 'the protein gap'. However, in 1974, an influential scientist loudly criticized these efforts in the respected medical journal The Lancet. He argued that children in developing countries were receiving sufficient protein from their diets, and that money was being wasted on costly efforts to provide protein. The pendulum swung in the direction of micronutrients as a more cost-effective and necessary solution. Perhaps, in the search for THE magic bullet, we have lost sight of the fact that things are seldom as simple as they may appear at first glance.

This too applies to the new research. Unfortunately, in the food democracy, not all proteins are created equal. There is a huge difference in nutrition and growth amongst children who receive their daily protein from maize versus from milk and eggs. Maize, a staple food in many countries where stunting is ubiquitous, is a poor source of essential amino acids. The proteins that contain all the essential amino acids and are a rich source of micronutrients are predominantly animal-source foods - milk, eggs, and meat. Sadly in the developing world, where stunting is rampant, families often survive on less than US$2 a day and for them animal-source foods are unaffordable.

Providing protein with sufficient levels of the essential amino acids will be a major challenge and will require substantial investment and innovations in the agricultural sector. The protein solution will also need to ensure the supply of the micronutrients if we are to avoid repeating our error. There are no quick fixes to this complex challenge and we would be wise to head the words of Albert Einstein, "Everything should be made as simple as possible, but not simpler." After forty years of what might be called 'protein neglect', the time has come for the nutrition community to start talking about food rather than nutrients.