Objective: To determine the effectiveness of combined iron and zinc over the iron or zinc-only supplementation in correcting deficiency and possible interactive effects in a group of adolescent school children.
Subjects and methods: Schoolchildren (n=821) of 12-16 years of age were randomized into four groups and supplemented with iron (50 mg/day), zinc (14 mg/day), iron+zinc or placebo capsules 5 days per week for 24 weeks. Anthropometry, and haemoglobin (Hb), serum zinc (SZn) and serum ferritin (SF) concentrations were determined before and after the intervention.
Results: There were no significant effects between-groups in their weight, height and Hb concentrations with the intervention when compared with the placebo group. Iron-only and combination-supplemented groups had reached mean SF concentrations of 55.1 microg/l with no difference between them (P=0.99). The zinc-only group had a mean change of 4.3 micromol//l whereas the combine-supplemented group had a mean change of 4.0 micromol/l (P=0.82). The prevalence of anaemia was found to be 70.3% in the iron group at baseline; this was reduced to 14.5% after the supplementation. In the combine-supplemented group anaemia, prevalence was reduced from 64.8 to 19.3%.
Conclusions: Zinc alone or in combination with iron has not shown a significant improvement in growth in adolescence. Severe and moderate forms of anaemia were successfully treated in children who received iron supplementation. Initial high prevalence of low SZn and iron stores was significantly improved with micronutrient supplementation.