IMPACT OF ZINC SUPPLEMENTATION ON GROWTH: A DOUBLE-BLIND, RANDOMIZED TRIAL AMONG URBAN IRANIAN SCHOOLCHILDREN

INTRODUCTION: The first study that linked zinc and growth was carried out in Iran and Egypt almost 3 decades ago. At the time, the circumstances leading to growth impairment secondary to zinc deficiency were believed to be unique in less developed countries. Multiple studies have been carried out to assess the effect of zinc supplementation on children's growth. The results of these studies have been inconsistent. OBJECTIVE: The aim of this study was to investigate the impact of zinc supplementation on growth (weight and height) among schoolchildren who were underweight or had stunted growth. METHODS: Our study was a randomized, double-blind, placebo-controlled trial of 90 Iranian urban schoolchildren (50 boys and 40 girls; 7–12 years old) who were underweight or stunted and were supplemented with 10 mg of zinc or placebo on school days for 6 months. Variables were weight and height. RESULTS: Significant effects on weight gain (2.037 ± 1.240 vs 1.55 ± 0.64 kg; P = .0167) and height (2.030 ± 1.003 vs 1.403 ± 0.521 cm; P = .0002) in the children after zinc supplementation versus placebo administration, respectively, were seen over the 6-month period. CONCLUSIONS: On the basis of this study, zinc supplementation improved growth in underweight or stunted children and should be considered for populations at risk for zinc deficiency, especially where there are elevated rates of underweight or stunting.