Assessments of the effects of nutrition on mental development and behavior in Jamaican studies.

Methodological issues and problems in studies of the effects of protein-energy malnutrition (PEM) and child development are discussed with reference to our experience in Jamaica. The usefulness of defining PEM by stunting, wasting, and edema is stressed. Difficulties in achieving reliable and valid measurements of mental development and behavior in Third World children, and allowing for the confounding and possibly interacting effects of social background, are discussed. Problems associated with different approaches are outlined.