A 14-mo zinc-supplementation trial in apparently healthy Chilean preschool children.

Apparently healthy preschool children (46 boys, 52 girls) aged 27-50 mo from low socioeconomic conditions who attended daycare centers in Santiago participated in a 14-mo long double-blind zinc supplementation trial. Unlike most previous studies, no additional inclusion criteria such as short stature or slow growth rate were considered. Subjects were pair matched according to sex and age and randomly assigned to two experimental groups: the supplemented group, which received 10 mg Zn/d, and the placebo group. Selected anthropometric, clinical, dietary, biochemical, and functional indexes were determined at the beginning of the study and after 6 and 14 mo of intervention. Actual dietary zinc intake was 66% of the recommended dietary allowance. Height gain after 14 mo was on average 0.5 cm higher in the supplemented group (P = 0.10). The response, however, was different between sexes. Boys from the supplemented group gained 0.9 cm more than those in the placebo group (P = 0.045). No effect was seen in girls. Although no significant differences were observed in the rest of the variables studied, trends (0.05 < P < 0.10) in the supplemented group compared with the placebo group for increased midarm muscle area in boys, improved response to tuberculin, and reduced rates of parasite reinfestation were noted. We conclude that in preschool children of low socioeconomic status, zinc is a limiting factor in the expression of growth potential.