A double-blind placebo controlled trial was conducted by Melaku Umeta et al. to examine the effect of a zinc supplement on growth, body composition, appetite, and morbidity in stunted and nonstunted rural Ethiopian infants aged 6-12 months. The infants were randomly assigned to a placebo or zinc supplement (zinc sulfate) administered as a syrup 6 days a week for 6 months. The study showed significant effects of zinc supplement on linear and ponderal growth in stunted and nonstunted infants. However, no significant changes in mid-arm circumference or triceps skinfolds were reported in the supplemented stunted infants despite improvements in their appetite. The positive growth response was attributed, in part, to a secondary impact of zinc on growth resulting from reductions in the incidence of anorexia, cough, diarrhea, fever, and vomiting in the stunted children. This study has shown that zinc is the primary growth-limiting nutrient during infancy in African children. However, whether zinc is the primary growth-limiting nutrient during infancy will depend on the ecological setting. Influencing factors include breast-feeding practices, dietary intake, infections, diarrhea, and prenatal and maternal malnutrition. Therefore, unless zinc is the primary growth-limiting nutrient, universal zinc supplementation will not improve the growth of stunted children.