Objectives: To determine the effect of low-dose weekly supplementation with iron, zinc or both on growth of infants from 6 to 12 months of age.
Subjects/methods: A total of 645 breastfed infants age 6 months who were not severely anemic (Hb> or = 90 g l(-1)) or severely malnourished (weight-for-age > or = 60% median) were randomized to receive 20 mg iron and 1 mg riboflavin; 20 mg zinc and 1 mg riboflavin; 20 mg iron, 20 mg zinc and 1 mg riboflavin; or riboflavin alone (control) weekly for 6 months.
Results: Baseline characteristics were similar among the four supplementation groups. Weight, length and mid-upper arm circumference were assessed at baseline, 8, 10 and 12 months of age. There was no interaction of iron and zinc when given in a combined supplement on either weight or length (P>0.05). There were no effects of either iron or zinc on the rate of length or weight gain for all infants or when stratified by baseline Hb concentration.
Conclusions: Weekly supplementation of 20 mg Fe, 20 mg Zn, or both does not benefit growth among infants 6-12 months of age in rural Bangladesh, a region with high rates of anemia and zinc deficiency.