Redistribution of vitamin A after iron supplementation in Indonesian infants.
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.


METHODS
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.
Wieringa
Frank T
FT
Division of Human Nutrition and Epidemiology, Wageningen University, Wageningen, Netherlands.
Dijkhuizen
Marjoleine A
MA
West
Clive E
CE
Thurnham
David I
DI
Muhilal
Van der Meer
Jos W M
JW
D000975:Antioxidants / Q000008:administration & dosage*; D019587:Dietary Supplements; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D007214:Indonesia; D007223:Infant; D007227:Infant Nutritional Physiological Phenomena; D007501:Iron / Q000008:administration & dosage* / Q000097:blood; D000090463:Iron Deficiencies; D008099:Liver / Q000378:metabolism; D008297:Male; D009752:Nutritional Status; D010919:Placebos; D014018:Tissue Distribution; D014801:Vitamin A / Q000097:blood* / Q000378:metabolism; D014802:Vitamin A Deficiency / Q000097:blood / Q000453:epidemiology; D015032:Zinc / Q000008:administration & dosage* / Q000097:blood / Q000172:deficiency; D019207:beta Carotene / Q000008:administration & dosage* / Q000097:blood
D000975:Antioxidants; D010919:Placebos; D019207:beta Carotene; D014801:Vitamin A; D007501:Iron; D015032:Zinc