The Relationship between Energy Intake and Diarrhoeal Disease in Their Effects on Child Growth: Biological Model, Evidence, and Implications for Public Health Policy

Abstract

The effects of both inadequate energy intake and diarrhoeal disease in the aetiology of childhood malnutrition are well established. Their relative importance is still debated, however, and the resultant uncertainty affects public health policies designed to improve child nutrition. This paper summarizes several earlier publications, and presents the results graphically to show that the same synergistic relationship holds across both urban and rural populations as well as across populations with differing levels of diarrhoea and malnutrition. The results show that the effect of inadequate energy intake on nutrition status depends on the level of diarrhoea, just as the negative effect of diarrhoea on nutrition status depends on the level of energy intake. The public health implications of these findings are threefold. First, an immediate strategy to improve child nutrition should focus on mechanisms to improve energy intake and dietary quality in general, and in and around the diarrhoeal episode in particular. Second, concurrently and as a long-term strategy, environmental conditions that put young children at risk for diarrhoea have to be improved. Finally, inasmuch as diarrhoea does not have a negative effect on growth among infants receiving the major part of their energy from breast milk, breast-feeding has a special and previously unrecognized role in the relationship between energy intake and diarrhoea as they affect nutrition status. Thus, efforts to promote increased energy intake and dietary quality among infants and young children should be coupled with efforts to promote breastfeeding exclusively through at least the first 4 months of life and partially through 24 months, when children are most at risk for diarrhoea.