Carmichael D, Christopher J, Hegenauer J, Saltman P
Am J Clin Nutr. 1975 May;28(5):487-93. doi: 10.1093/ajcn/28.5.487.
Milk is an attractive vehicle for introducing iron supplements into iron-deficient infants and children. This study compares the effects of milk and caseins on the whole-body absorption of radioactive iron complexes in an attempt to resolve the controversy over whether milk and its constituent phosphoproteins seriously impair iron absorption. Evidence is presented to clarify the role of the calcium-casein micelles of cow's milk in binding iron donated by the ferric-nitrilotriacetate (NTA) complex. The absorption of iron from isolated Fe(III)-casein complexes was studied in mice as a function of the casein--to--Fe ratio and was compared with the absorption of Fe(III)-NTA at equivalent levels. Even at casein--to--Fe ratios higher than those found in conventional iron-supplemented cow's milk (10-15 mg Fe/qt; casein P:Fe congruent to 34), absorption of iron(III) from the casein or NTA complex was not significantly different. There was no significant difference in the absorption of iron administered to mice and chicks as ferrous ion, ferric-NTA, or ferric fructose; nonfat cow's milk did not inhibit the absorption of these iron compounds. For the chick, in fact, milk significantly enhanced the absorption of iron from the ferric-NTA chelate. In order to affect iron absorption significantly casein would have to be present considerably in excess of that found in conventionally supplemented cow's milk.
牛奶是向缺铁婴幼儿补充铁剂的理想载体。本研究比较了牛奶和酪蛋白对放射性铁络合物全身吸收的影响，以解决关于牛奶及其组成磷蛋白是否严重损害铁吸收的争议。本文提供的证据阐明了牛奶中酪蛋白钙胶束在结合由次氮基三乙酸铁（NTA）络合物提供的铁方面的作用。在小鼠中研究了从分离的Fe(III)-酪蛋白络合物中吸收铁的情况，作为酪蛋白与铁比例的函数，并与等量水平下Fe(III)-NTA的吸收情况进行了比较。即使酪蛋白与铁的比例高于常规添加铁的牛奶中的比例（10 - 15毫克铁/夸脱；酪蛋白磷：铁约为34），从酪蛋白或NTA络合物中吸收的铁(III)也没有显著差异。以亚铁离子、铁-NTA或铁果糖形式给小鼠和雏鸡施用铁，其吸收没有显著差异；脱脂牛奶不抑制这些铁化合物的吸收。事实上，对于雏鸡来说，牛奶显著增强了从铁-NTA螯合物中吸收铁的能力。为了显著影响铁的吸收，酪蛋白的含量必须大大超过常规添加牛奶中的含量。
