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In 1993 the International Dietary Energy Consultative Group (IDECG) formed a task force with the mandate to assess current knowledge of the relationship between undernutrition and behavioral development in children. Justification was the availability of new information from clinical trials of dietary and iron supplementation, follow-up of previously supplemented children, and studies of specific nutrients and contextual risk factors as predictors of functional competence at different ages. Each member of the task force wrote a paper for a meeting held in December 1993 at the University of California, Davis, where the group discussed the main issues and produced an early draft of the summary report. The edited versions of those papers, as well as invited papers by Larry Brown and Laura Sherman and by Ricardo Uauy and Isidora de Andraca, comprise the present supplement of the Journal of Nutrition. The revised summary report will be published elsewhere.
These papers review what members of the task force believe are critical theoretical and empirical issues related to the effects of undernutrition on the development of human behavior. One intent was to assess existing knowledge in light of current theories in nutrition and developmental psychobiology. The previously accepted explanation for the effects of nutrition on development, which emphasized protein energy malnutrition (PEM), postulated that PEM stunts brain growth and thereby has a direct, independent effect on brain function. This explanation now appears too simplistic in light of more recent evidence that suggests that PEM is not a distinct clinical entity but, rather, a syndrome having multiple causal factors. It coexists with other nutritional deficiencies and imbalances that not only divert development from a normal trajectory but also affect central nervous system (CNS) function. Development is further affected by nutrient interactions and other health status variables. Moreover, the social context in which PEM occurs can either attenuate or enhance the developmental risk of malnourished children.
Although in the past there was general agreement that severe undernutrition alters the trajectory of human behavior, skepticism prevailed regarding the functional consequences of mild-to-moderate undernutrition. The reviews in this supplement document sufficient evidence to conclude that even the most prevalent levels of general undernutrition represent a risk factor that increases the probability of deviating human development from its normal trajectory. It is hoped that concerned policy makers will benefit from the political implications discussed in this supplement.
We gratefully acknowledge the sponsorship of IDECG, the International Union of Nutritional Sciences, Kraft Foods and the Nestle Foundation.
Ernesto Pollitt, Chair
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