Wieringa Frank T, Dijkhuizen Marjoleine A, West Clive E, Thurnham David I, Van der Meer Jos W M
Division of Human Nutrition and Epidemiology, Wageningen University, Wageningen, Netherlands.
Am J Clin Nutr. 2003 Mar;77(3):651-7. doi: 10.1093/ajcn/77.3.651.
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.
This study investigated interactions among 3 important micronutrients--iron, vitamin A, and zinc--when they are given as supplements.
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.
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.
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.
铁和维生素A缺乏在全球普遍存在。单一微量营养素补充剂被广泛用于对抗这些缺乏症。然而，微量营养素缺乏往往同时发生，并且微量营养素之间存在许多相互作用。
本研究调查了三种重要微量营养素——铁、维生素A和锌——作为补充剂时的相互作用。
在一项随机、双盲、安慰剂对照的补充试验中，387名4个月大的印度尼西亚婴儿每周5天、持续6个月补充10毫克铁、10毫克锌、2.4毫克β-胡萝卜素、铁和锌各10毫克、10毫克锌 + 2.4毫克β-胡萝卜素或安慰剂。在研究结束时，从256名婴儿中获得了关于微量营养素状况的完整数据，包括血红蛋白、铁蛋白、视黄醇、锌以及改良相对剂量反应（肝脏视黄醇储备的一种测量方法）。
与未补充铁的婴儿相比，补充铁的婴儿血浆视黄醇浓度显著降低，且血浆视黄醇浓度<0.70微摩尔/升定义的维生素A缺乏患病率显著更高。相比之下，补充铁的婴儿的改良相对剂量反应表明肝脏视黄醇储备更多。补充铁改善了铁状况，补充锌改善了锌状况，但补充β-胡萝卜素并未显著改善维生素A状况。
在本研究中，对维生素A边缘状态的婴儿补充铁导致血浆维生素A浓度降低，同时肝脏维生素A储备增加。这意味着补充铁后视黄醇重新分布，这可能诱发维生素A缺乏。因此，婴儿补充铁时应采取措施改善维生素A状况。
