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

Am J Clin Nutr. 2002 Jan;75(1):92-8. doi: 10.1093/ajcn/75.1.92.


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.

Results: Mean serum retinol concentrations were not significantly different between the A and ZA groups. Among vitamin A-deficient children, the proportion of children who remained vitamin A deficient (serum retinol <0.7 micromol/L) after supplementation was 40.6% in the Z group, 37.5% in the A group, and 47.0% in the placebo group; only 13.3% in the ZA group remained vitamin A deficient (P < 0.05 compared with the placebo group). The proportion of children whose retinol binding protein concentrations remained low was significantly lower in the ZA group than in the other groups (P < 0.05).

Conclusion: Combined zinc and vitamin A supplementation improves vitamin A nutriture in vitamin A-deficient children.

Publication types

  • Clinical Trial
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anthropometry
  • Bangladesh
  • Biological Availability
  • Chi-Square Distribution
  • Child, Preschool
  • Dietary Supplements*
  • Double-Blind Method
  • Drug Synergism
  • Female
  • Humans
  • Infant
  • Male
  • Nutritional Status
  • Vitamin A / blood
  • Vitamin A / pharmacokinetics
  • Vitamin A / therapeutic use*
  • Vitamin A Deficiency / complications
  • Vitamin A Deficiency / drug therapy*
  • Zinc / blood
  • Zinc / deficiency*
  • Zinc / therapeutic use*


  • Vitamin A
  • Zinc