The Effect of Zinc Supplementation on Linear Growth and Growth Factors in Primary Schoolchildren in the Suburbs Mashhad, Iran

Background: Zinc is an essential trace element required for the functional activity of several enzyme systems. Several studies have been carried out to assess the effect of zinc supplementation on children’s growth, but controversy exists as to the effect of zinc on growth and GH-IGF-I system. Objective:  The aim of this study was to evaluate the effect of zinc supplementation on linear growth and serum level of  IGF-I, Ca ,P, ALP in elementary school children living in a low socioeconomic suburb of Mashhad in Northeast of Iran. Methods: The study was a randomized double-blind, placebo-controlled efficacy trial. Subjects were 200 volunteer primary school children. Both case and control groups comprised of 100 individuals each with 50 males and 50 females. Intervention supplementation was zinc sulfate tablets (10 mg elemental) and placebo tablets for both groups, administrated for a period of six months. The height, weight, height for age and weight for age Z-scores and Body Mass Index were measured at 0,2,4, and 6 months. After six months the level of IGF-I, calcium, phosphorus and alkaline phosphatase were measured using blood samples taken from 50 volunteer children, 33 from the case and 17 from the control group. The results were compared in the two groups. Results: There was a significant increase (p<0.05) in linear growth and weight amongst both male and female of the case group compared to the control after six months of receiving zinc. However, there was no significant difference in the serum level for the measured parameters between the two groups. Conclusion: This study provides evidence of positive effect of zinc supplementation on the growth of school children living in a low socioeconomic suburb of Mashhad city in Iran.