The effect of zinc-supplemented bread consumption on school children with asymptomatic zinc deficiency

Background: Zinc deficiency has been seen in developing countries in which grain-based vegetable protein is consumed more often than animal protein. This study was done to emphasize the importance of zinc-fortified foods and to investigate bioavailability of zinc in zinc-fortified bread. Methods: Serum zinc concentrations in healthy 7- to 11-year-old school children were determined. In 24 of 101 children serum zinc concentrations were below 65 μg/dl. These 24 children with asymptomatic zinc deficiency were divided into two equal groups. The 12 children with low serum zinc concentrations received the zinc-fortified bread providing 2 mg/kg/day elemental zinc acetate for 90 days (zinc-supplemented group), whereas the other 12 children received the same quality bread with no zinc fortification (control group). Results: By the end of the period, the zinc-supplemented group had significantly higher serum and leukocyte zinc concentrations (p < 0.01) and the weight, serum albumin levels, and alkaline phosphatase increased (p < 0.01). Immune functions improved, evidenced by conversion of delayed hypersensitivity skin reactions. Zinc-fortified bread (2 mg/kg/day) caused no side effects or manifestations of zinc toxicity. Conclusions: The results indicate that the bioavailability of zinc in the bread is satisfactory. The use of zinc-fortified bread was found to be an economical and readily accessible method to eliminate zinc deficiency and to prevent further occurrence.