Synergistic effect of zinc and vitamin A on the biochemical indexes of vitamin A nutrition in children.
Level 2 - randomized trial
Individual randomized double-blind placebo-controlled trial
PubMed 11756065 · doi:10.1093/ajcn/75.1.92
What was done
A randomized, double-blind, placebo-controlled trial evaluated whether combined zinc and vitamin A supplementation improved biochemical markers of vitamin A status in children aged 12 to 35 months. Participants were assigned to one of four groups: 20 mg/d zinc for 14 days (Z group), 60,000 retinol equivalents (200,000 IU) vitamin A on day 14 (A group), zinc plus vitamin A (ZA group), or placebo syrup and capsule. Venous blood was drawn at enrollment and on day 21 to measure serum retinol and retinol-binding protein concentrations.
What was found
Mean serum retinol concentrations did not differ significantly between the A and ZA groups. Among children who were vitamin A-deficient at baseline, the proportion remaining deficient (serum retinol <0.7 micromol/L) after supplementation was 47.0% in the placebo group, 40.6% in the Z group, 37.5% in the A group, and 13.3% in the ZA group (P < 0.05 compared with placebo). The proportion of children whose retinol-binding protein concentrations remained low was also significantly lower in the ZA group than in the other groups (P < 0.05).
Why it matters
This study demonstrates that zinc enhances the biochemical response to vitamin A supplementation in deficient children, supporting combined micronutrient strategies in populations where dual deficiencies are prevalent.
Limits
The total sample size, participant breakdown per group, and study location are not reported in the abstract. Outcomes were limited to short-term biochemical indices at day 21 without assessment of clinical or functional endpoints.
Cited by
- supports Vitamin A will not work effectively in the body if a person is deficient in zinc.