Redistribution of vitamin A after iron supplementation in Indonesian infants.
What this study found
Iron supplementation worsened vitamin A status by lowering plasma retinol while increasing liver vitamin A stores, consistent with redistribution of retinol from plasma to the liver. After 6 months, plasma retinol was 0.62 ± 0.17 in the iron group and 0.56 ± 0.17 in the iron plus zinc group versus 0.74 ± 0.26 in placebo; hemoglobin and ferritin improved with iron, with ferritin 38.2 (18.0-68.1) and 31.7 (17.4-41.6) versus 15.2 (8.2-28.1). Zinc-containing regimens improved zinc status, with plasma zinc 15.5 (13.8-19.0) to 16.5 (13.7-21.0) versus 14.2 (11.9-15.9) in placebo. Beta-carotene…
- Study & population
- Masked supplementation trial in Indonesian infants recruited at about 4 months of age from 6 villages in rural Bogor District, West Java, Indonesia, and followed for 6 months.
- Intervention
- Infants received oral micronutrient syrup and/or oil 5 days per week for 6 months.
- Key limitation
- Single rural Indonesian infant cohort limits generalizability.
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Open PDFOriginal abstract
BACKGROUND Deficiencies of iron and vitamin A are prevalent worldwide. Single-micronutrient supplementation is widely used to combat these deficiencies. However, micronutrient deficiencies often occur concurrently, and there are many interactions between micronutrients. OBJECTIVE This study investigated interactions among 3 important micronutrients--iron, vitamin A, and zinc--when they are given as supplements. DESIGN In a randomized, double-blind, placebo-controlled supplementation trial, 387 Indonesian infants aged 4 mo were supplemented 5 d/wk for 6 mo with 10 mg Fe, 10 mg Zn, 2.4 mg beta-carotene, 10 mg each of Fe and Zn, 10 mg Zn + 2.4 mg beta-carotene, or placebo. Complete data on micronutrient status, including hemoglobin, ferritin, retinol, zinc, and the modified relative dose response (a measure of liver retinol stores), were available from 256 infants at the end of the study. RESULTS Iron-supplemented infants had significantly lower plasma retinol concentrations and a significantly higher prevalence of vitamin A deficiency, as defined by a plasma retinol concentration <0.70 micromol/L, than did the non-supplemented infants. In contrast, the modified relative dose response of the iron-supplemented infants indicated greater liver stores of vitamin A. Iron supplementation improved iron status, and zinc supplementation improved zinc status, but beta-carotene supplementation did not significantly improve vitamin A status. CONCLUSIONS In this study, iron supplementation in infants with marginal vitamin A status led to lower plasma vitamin A concentrations and simultaneously to greater vitamin A liver stores. This implies a redistribution of retinol after iron supplementation, which might induce vitamin A deficiency. Therefore, iron supplementation in infants should be accompanied by measures to improve vitamin A status.