Effect of zinc plus multivitamin supplementation on growth in school children

BackgroundZinc and multiple vitamins are essential for growth. Zinc and vitamin deficiency is very common in developing countries. The aim of this study was to assess the efficacy of zinc plus multivitamin supplements in improving growth of healthy Thai schoolchildren. MethodsA randomized controlled trial was conducted in healthy 4-13-year-old Thai schoolchildren attending public school in central Thailand. Participants were randomized to receive either chelated zinc in the form of zinc bis-glycinate (20 mg elemental zinc) plus multivitamins (vitamin A, 1000 IU; vitamin D, 200 IU; B1, 10 mg; B2, 3 mg; B6, 1 mg; B12, 10 g; nicotinamide, 40 mg) or placebo once per day, 5 days per week for 6 months. Primary outcome was change in height from baseline to the end of the study. Secondary outcomes were change in weight, body mass index, waist and hip circumferences and waist-to-height ratio. An intention-to-treat analysis was performed. ResultsSeventy children each were randomized to the treatment and placebo groups. The children who received zinc and multivitamins had significantly higher gain in height (4.9 1.3 vs 3.6 +/- 0.9 cm, respectively; P < 0.001). Subgroup analysis showed significant improvement in height, especially in preadolescents. The increased gain in height was irrespective of baseline height and weight. The extra gain in height occurred after 2 months of supplementation. The changes in other anthropometric indices were not significantly different. ConclusionSupplementation of chelated zinc plus multivitamins for 6 months significantly increased height gain in Thai schoolchildren and was well tolerated.