Research in several countries has shown a clear association between protein calorie malnutrition in children and subsequent below-average scores on “intelligence” tests. Certain social, environmental and possibly genetic variables may affect both physical and mental development. It is, therefore, not yet known if this association is one of cause and effect, especially in mild or moderate malnutrition. A longitudinal study in Bogota, Colombia is investigating this problem using sex matched siblings. The research design allows some control of environmental and genetic factors. It has often been a problem in home supplementation programs to know whether any food supplement is, in fact, consumed by the target-children. Up to the present there has been no easy field test for evaluation of the utilization of supplements. In the Bogota study the use of D-xylose added to milk powder as a “tracer” has proved feasible and useful. The recent consumption of the supplement can be determined by a simple urine test. A battery of psychological tests has been chosen, validated and standarized for the Bogota study. They include traditional I.Q. instruments and also cognitive tests based on Piagetian psychology. Preliminary results indicate that the mean scores vary considerably both with nutritional status and with social class using the Griffiths Scale. In contrast the Piagetian tests show very small differences with social class.
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