Effect of zinc and iron supplementation on vitamin A status of primary school children

Background: Micronutrients deficiency is one of the most health problems in the world. Iron and zinc deficiency and their interaction with vitamin A are important, too. The aim of this study was to investigate the effects of supplementation of iron and zinc, alone or combined, on vitamin A status of primary school children. Material and methods: The study was a randomized double-blind clinical trial in which 81 primary school children, 11 y of age, were randomly supplemented for 4 months with iron (20 mg/d), zinc (20 mg/d), or iron+ zinc (20 mg of each/d). Plasma retinol was measured at beginning and after 4 months by HPLC method. SPSS version 11.5 software was used. Data were analyzed by ANOVA, and paired t test. Results: Plasma retinol changes in Iron, zinc, and iron +zinc groups were: -0.1±0.2, -0.1±0.1, -0.1±0.1 µmol/L, respectively. These changes in female and male were, respectively: -0.18±0.2, -0.03±0.1 for iron group, -0.1±0.1, -0.08±0.09 for zinc group, and -0.14±0.2, -0.06±0.1 for iron + zinc group retinol decreased in all supplemented groups. Deficient or non-deficient basal serum zinc had no effect on result. Conclusion: Plasma retinol was decreased in all supplemented groups. As, decrease in plasma retinol results from the supplementation, more studies should be carried out on this subject.