Ameny Michael A, Raila Jens, Walzel Erwin, Schweigert Florian J
Institute of Nutritional Science, University of Potsdam, Rehbrücke, Germany.
J Trace Elem Med Biol. 2002;16(3):175-8. doi: 10.1016/S0946-672X(02)80021-9.
Iron and vitamin A deficiency are common nutritional problems in developing countries. From animal experiments and intervention studies, growing evidence is pointing to a possible influence of iron on vitamin A metabolism. We assessed the affects of an oral supplementation of vitamin A and/or iron on the recovery of rats from vitamin A and iron deficiency. Weanling male Wistar rats were kept for four weeks on an iron and vitamin A deficient diet. Thereafter, rats were repleted with iron 35 mg/kg feed, with vitamin A 4500 IU/kg feed both, or with iron 35 mg/kg and vitamin A 4500 IU/kg for five weeks. Retinol and retinyl esters in plasma and tissues were determined by HPLC. Iron was determined by atomic absorption spectrophotometry. The determination of haematological parameters showed that rats developed an anaemia during depletion. This was reversed by the re-supplementation with iron but not vitamin A alone. The simultaneous supplementation of vitamin A was of no additional benefit. When rats were re-supplemented with iron alone a substantial further decrease in plasma retinol (P < 0.002) and liver vitamin A (P < 0.05) was observed. A similar but less pronounced decrease in plasma retinol was observed in the rats re-supplemented with vitamin A alone, despite a substantial increase in liver vitamin A (P < 0.002). Despite lower liver vitamin A levels compared to the group re-supplemented with vitamin A alone, the group re-supplemented with iron and vitamin A had substantial higher plasma levels compared to the one supplemented with iron alone (P < 0.002). In conclusion, the study supports an interaction of iron and vitamin A on the level of retinol transport in plasma. Despite a comparable availability of vitamin A as indicated by the comparable liver levels only the re-supplementation of both iron and vitamin A can normalize the retinol level in plasma. This might be of nutritional consequence in developing countries with regard to the supplementation regime of both nutrients iron and vitamin A to prevent a functional deficiency of vitamin A despite sufficient dietary availability.
铁和维生素A缺乏是发展中国家常见的营养问题。从动物实验和干预研究来看，越来越多的证据表明铁可能会影响维生素A的代谢。我们评估了口服补充维生素A和/或铁对维生素A和铁缺乏大鼠恢复情况的影响。将断乳雄性Wistar大鼠置于缺铁和维生素A的饮食环境中饲养四周。此后，大鼠分别以每千克饲料补充35毫克铁、每千克饲料补充4500国际单位维生素A、每千克饲料同时补充35毫克铁和4500国际单位维生素A的方式进行为期五周的补充。通过高效液相色谱法测定血浆和组织中的视黄醇和视黄酯。通过原子吸收分光光度法测定铁含量。血液学参数的测定表明，大鼠在营养缺乏期间出现了贫血。补充铁可逆转贫血，而单独补充维生素A则不能。同时补充维生素A并无额外益处。当大鼠仅补充铁时，血浆视黄醇（P < 0.002）和肝脏维生素A（P < 0.05）大幅进一步下降。单独补充维生素A的大鼠血浆视黄醇也出现了类似但不太明显的下降，尽管肝脏维生素A大幅增加（P < 0.002）。与仅补充铁的组相比，同时补充铁和维生素A的组尽管肝脏维生素A水平低于仅补充维生素A的组，但其血浆水平却显著更高（P < 0.002）。总之，该研究支持铁和维生素A在血浆视黄醇转运水平上存在相互作用。尽管肝脏水平表明维生素A的可利用性相当，但只有同时补充铁和维生素A才能使血浆视黄醇水平恢复正常。在发展中国家，这对于铁和维生素A这两种营养素的补充方案可能具有营养方面的影响，即尽管饮食中维生素A充足，但仍可预防维生素A的功能性缺乏。
