García-Casal M N, Layrisse M, Solano L, Barón M A, Arguello F, Llovera D, Ramírez J, Leets I, Tropper E
Centro de Medicina Experimental, Laboratorio de Fisiopatología, Instituto Venezolano de Investigaciones Científicas (IVIC), Caracas 1020A, Venezuela.
J Nutr. 1998 Mar;128(3):646-50. doi: 10.1093/jn/128.3.646.
After the rapid decrease in the prevalence of iron deficiency and iron-deficiency anemia in the Venezuelan population when a national program for fortification of flours with iron and vitamins was instituted, we studied micronutrient interactions in Venezuelan diets. One hundred human adults were fed three cereal-based diets, labelled with either 59Fe or 55Fe in six studies. Each diet contained different concentrations of vitamin A (from 0.37 to 2.78 micromol/100 g cereal) or beta-carotene (from 0.58 to 2.06 micromol/100 g cereal). The presence of vitamin A increased iron absorption up to twofold for rice, 0.8-fold for wheat and 1.4-fold for corn. beta-carotene increased absorption more than threefold for rice and 1.8-fold for wheat and corn, suggesting that both compounds prevented the inhibitory effect of phytates on iron absorption. Increasing the doses of vitamin A or beta-carotene did not further significantly increase iron absorption. We measured the iron remaining in solution performing in vitro studies in which the pH of solutions was adjusted from 2 to 6 in the presence of vitamin A or beta-carotene. All of the iron from ferrous fumarate was soluble after changing the pH of the solution containing 3.4 micromol of beta-carotene to 6.0. Vitamin A was less effective. However, 78 +/- 18% of iron was soluble in the presence of 3.3 micromol of vitamin A, whereas with no vitamin addition, only 26 +/- 13% of iron was soluble (<0.05). Vitamin A and beta-carotene may form a complex with iron, keeping it soluble in the intestinal lumen and preventing the inhibitory effect of phytates and polyphenols on iron absorption.
在委内瑞拉实施一项用铁和维生素对面粉进行强化的国家计划后，该国缺铁和缺铁性贫血的患病率迅速下降，我们对委内瑞拉饮食中的微量营养素相互作用进行了研究。在六项研究中，给100名成年人喂食了三种以谷物为基础的饮食，这些饮食分别用59Fe或55Fe进行标记。每种饮食含有不同浓度的维生素A（从0.37至2.78微摩尔/100克谷物）或β-胡萝卜素（从0.58至2.06微摩尔/100克谷物）。维生素A的存在使大米中铁的吸收增加了两倍，小麦中铁的吸收增加了0.8倍，玉米中铁的吸收增加了1.4倍。β-胡萝卜素使大米中铁的吸收增加了三倍多，小麦和玉米中铁的吸收增加了1.8倍，这表明这两种化合物都能防止植酸盐对铁吸收的抑制作用。增加维生素A或β-胡萝卜素的剂量并没有进一步显著增加铁的吸收。我们通过体外研究测量了溶液中剩余的铁，在这些研究中，在维生素A或β-胡萝卜素存在的情况下将溶液的pH值从2调节到6。在含有3.4微摩尔β-胡萝卜素的溶液的pH值变为6.0后，富马酸亚铁中的所有铁都可溶。维生素A的效果较差。然而，在存在3.3微摩尔维生素A的情况下，78±18%的铁可溶，而不添加维生素时，只有26±13%的铁可溶（<0.05）。维生素A和β-胡萝卜素可能与铁形成复合物，使其在肠腔内保持可溶，并防止植酸盐和多酚对铁吸收的抑制作用。
