“The human mind is our fundamental resource.” – John F. Kennedy, 1961
In a recent study published in the Journal of Nutrition, we found that consuming high-iron biofortified pearl millet improved cognitive function in iron-deficient Indian adolescents. What do we mean by cognitive function? How did we attribute its improvement to biofortified pearl millet? What are the implications of these findings on a broader scale? I will try to briefly answer these questions here.
The brain has an extreme appetite. In adults, it only accounts for 2 percent of body weight but consumes 20 percent of the energy produced by the body. For example, if you consumed 2000 calories yesterday, about 400 of those calories were used to carry out brain processes. In addition to calories, the brain requires key nutrients to perform its functions. One of these is iron.
Iron, the most abundant element on Earth in terms of mass, is a basic requirement for the existence of most known life forms, and plays several important roles in the brain. I will mention three of those roles. First, iron is a cofactor for mitochondrial enzymes involved in producing energy, so the brain wouldn’t be able to function without it. Second, special cells called oligodendrocytes require iron to produce myelin, a fatty substance wrapped around neurons like insulation around a wire. Myelin allows cells in the central nervous system to rapidly transmit signals. Third is iron’s role in neurotransmitter synthesis. Neurotransmitters are chemicals that, along with electrical impulses, convey signals from one neuron to another, allowing the nervous system to communicate across the brain and body.
Since we studied living humans in a field setting, we couldn’t measure the amount of iron or neurotransmitters in the brain. However, we could measure the amount of iron in the blood, and we could measure behavior, a product of how well the brain functions, which depends on iron as I’ve described. In our study, we measured behavior by having the students play a set of five computer-based “brain games” that measure attention and memory. We designed the study so that we could attribute improvements in performance—how fast and how well the students played the games—to the consumption of biofortified pearl millet.
We compared the performance of a random group of students who consumed biofortified pearl millet in school meals over six months to another random group of students who consumed another variety of pearl millet lower in iron content. The millet was provided in the form of bhakri, a local flatbread, and shev, a savory snack made from extruded pearl millet flour. The students, aged 12-16, attended the same school; the pearl millet items were provided free. We measured cognitive function with the computer-based tests before they started eating the pearl millet and again after the six months had passed. By randomly assigning each student to one of the two groups, we tried to reduce differences between the groups that could account for measured differences in cognitive performance.
We found that consumption of biofortified pearl millet raised blood levels of iron faster and improved attention and memory more than did the lower iron pearl millet. A note of caution: This tightly-controlled efficacy trial in a single school provides proof of concept, but is not meant to describe what would actually happen in the real world. Any real-world impact would have to be assessed in an effectiveness trial. However, assuming farmers in low income countries adopt high-iron biofortified crops and those crops reach iron-deficient individuals (one important avenue in India may be the government’s school feeding program, the Midday Meal Scheme), our results suggest a way biofortification could make a meaningful contribution to society’s most fundamental resource, the human mind.
Samuel Scott is an Associate Research Fellow in IFPRI’s Poverty, Health, and Nutrition Division, based in New Delhi.
