Iron and/or zinc supplementation did not reduce blood lead concentrations in children in a randomized, placebo-controlled trial

There is increasing interest in the interaction of nutritional deficiencies with toxic metals. Iron deficiency and elevated blood lead concentrations (PbB) reportedly occur together, and zinc also plays an important role in lead metabolism. The objective was to evaluate the effect of zinc and/or iron supplementation on PbB of children attending schools in the neighborhood of a smelter complex for 6 mo. We conducted a double-blind, placebo-controlled field trial in 9 elementary schools located within a 3.5-km radius of a metal foundry in Torreón, Mexico. Of the 602 first-graders enrolled, 517 completed supplementation and had initial and final PbBs. Children were given either 30 mg of iron, 30 mg of zinc, both, or a placebo daily for 6 mo. Baseline and final measures included nutritional status and PbB. The overall prevalence of iron and zinc deficiencies was 12.1 and 30.3%, respectively, and 10.3% were anemic. The PbB concentration decreased in all experimental groups (P