Zinc Supplementation Enhances Linear Growth in School-Aged Children: A Randomized Controlled Trial

Zinc supplementation in children in endemic area of zinc deficiency had been reported of growth enhancement; however, the results were inconsistence. This study aimed to evaluate the efficacy of zinc supplementation on growth of school-aged children. A randomized double-blinded controlled trial was conducted in 140 Thai school children. Placebo or zinc bisglycinate (15 mg element zinc) were taken on school day for 6 months. Pre- and posttreatment anthropometric parameters were recorded. Changes in height from the baseline was considered as the primary outcome whereas, changes in other anthropometric parameters were considered as the secondary outcomes. The mean age was 8.9 years; baseline anthropometric data were not significant different between groups. At the end of study, children in zinc group had significantly higher gain in height (5.6±2.4 vs 4.7±1.4 cm, respectively; P=0.009) and height Z-score (0.45±0.37 vs 0.37±0.27, respectively; P=0.048) than children in control group. No significant differences of other anthropometric parameters were observed. In conclusion, zinc supplementation increased linear growth in Thai schoolaged children over a 6-month period but it had no effects on other anthropometric parameters.