Does Undernutrition during Infancy Inhibit Brain Growth and Subsequent Intellectual Development?

Experiments at Cambridge have shown that undernutrition during the early period of growth of calves will result in a reduction in size of the mature animal even if a high level of feeding is subsequently given, whereas a similar period of undernutrition in the 2-year-old animal, which was well fed as a calf, has much less effect on the mature size (Brookes and Vincett, 1950). The slower maturing zebu (Bos indicus) variety of cattle, which is bred in South Africa, appears to be less affected in their mature size by undernutrition when calves. These findings justify making a fairly obvious hypothesis that undernutrition may influence the mature size of an animal according to the age at which it occurs -the greatest effect being at the period of maximum growth-and by its duration relative to the total period of growth. When applied to human nutrition, this concept suggests that undernutrition during infancy might result in some reduction in the adult body size, but seeing that growth continues for 18 years, providing subsequent nutrition is good, the effect should be limited. There is, however, a notable exception, that is the brain. The first two years of life are not only the period of maximum growth-70% of the adult brain weight is reached by the end of the first year-but also they constitute almost the entire period of brain growth (Fig. 1). The interesting possibility arises that undernutrition during infancy may result in failure of the brain to achieve its full potential in size, and it is not unreasonable to suppose that this may also predispose to inhibition of optimum intellectual and personality development. To test this hypothesis, a group of infants was selected who, solely due to undernutrition, were grossly underweight when they were first seen. They were matched with an adequately nourished control group from an approximately similar socio-economic background. A comparative longitudinal study of head circumference, and physical and intellectual development of the two groups is reported. It was not possible to assess personalities of the mothers and children.