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

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. 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. 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. 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.