Synergistic effect of zinc and vitamin A on the biochemical indexes of vitamin A nutrition in children

Background Zinc deficiency limits the bioavailability of vitamin A. Because zinc and vitamin A deficiency often coexist in malnourished children, simultaneous zinc and vitamin A supplementation may improve the vitamin A deficiency in these children. Objective A randomized, double-blind, placebo-controlled intervention trial was conducted to evaluate whether combining zinc and vitamin A supplementation would improve the biochemical indexes of vitamin A nutriture. Design Children aged 12-35 mo were randomly assigned to 1 of 4 intervention groups: 20 mg Zn/d for 14 d (Z group), 60000 retinol equivalents (200000 IU) vitamin A on day 14 (A group), zinc plus vitamin A (ZA group), or placebo syrup and placebo capsule (placebo group). Venous blood was drawn at enrollment and on day 21.…