Zhu Le, Glahn Raymond P, Nelson Deanna, Miller Dennis D
Department of Human Biology, University of Wisconsin-Green Bay, Green Bay, Wisconsin 54311, USA.
J Agric Food Chem. 2009 Jun 10;57(11):5014-9. doi: 10.1021/jf900328t.
Iron bioavailability from supplements and fortificants varies depending upon the form of the iron and the presence or absence of iron absorption enhancers and inhibitors. Our objectives were to compare the effects of pH and selected enhancers and inhibitors and food matrices on the bioavailability of iron in soluble ferric pyrophosphate (SFP) to other iron fortificants using a Caco-2 cell culture model with or without the combination of in vitro digestion. Ferritin formation was the highest in cells treated with SFP compared to those treated with other iron compounds or chelates. Exposure to pH 2 followed by adjustment to pH 7 markedly decreased FeSO(4) bioavailability but had a smaller effect on bioavailabilities from SFP and sodium iron(III) ethylenediaminetetraacetate (NaFeEDTA), suggesting that chelating agents minimize the effects of pH on iron bioavailability. Adding ascorbic acid (AA) and cysteine to SFP in a 20:1 molar ratio increased ferritin formation by 3- and 2-fold, respectively, whereas adding citrate had no significant effect on the bioavailability of SFP. Adding phytic acid (10:1) and tannic acid (1:1) to iron decreased iron bioavailability from SFP by 91 and 99%, respectively. The addition of zinc had a marked inhibitory effect on iron bioavailability. Calcium and magnesium also inhibited iron bioavailability but to a lesser extent. Incorporating SFP in rice greatly reduced iron bioavailability from SFP, but this effect can be partially reversed with the addition of AA. SFP and FeSO(4) were taken up similarly when added to nonfat dry milk. Our results suggest that dietary factors known to enhance and inhibit iron bioavailability from various iron sources affect iron bioavailability from SFP in similar directions. However, the magnitude of the effects of iron absorption inhibitors on SFP iron appears to be smaller than on iron salts, such as FeSO(4) and FeCl(3). This supports the hypothesis that SFP is a promising iron source for food fortification and dietary supplements.
补充剂和强化剂中铁的生物利用率因铁的形式以及铁吸收增强剂和抑制剂的存在与否而有所不同。我们的目标是使用Caco-2细胞培养模型，在有或没有体外消化相结合的情况下，比较pH值、选定的增强剂和抑制剂以及食物基质对可溶性焦磷酸铁（SFP）中铁的生物利用率与其他铁强化剂的影响。与用其他铁化合物或螯合物处理的细胞相比，用SFP处理的细胞中形成的铁蛋白最多。先暴露于pH 2然后调至pH 7会显著降低硫酸亚铁（FeSO₄）的生物利用率，但对SFP和乙二胺四乙酸铁钠（NaFeEDTA）的生物利用率影响较小，这表明螯合剂可将pH值对铁生物利用率的影响降至最低。以20:1的摩尔比向SFP中添加抗坏血酸（AA）和半胱氨酸，铁蛋白的形成分别增加了3倍和2倍，而添加柠檬酸盐对SFP的生物利用率没有显著影响。向铁中添加植酸（10:1）和单宁酸（1:1），分别使SFP的铁生物利用率降低了91%和99%。添加锌对铁的生物利用率有显著抑制作用。钙和镁也会抑制铁的生物利用率，但程度较小。将SFP添加到大米中会大大降低SFP的铁生物利用率，但添加AA可部分逆转这种影响。当添加到脱脂奶粉中时，SFP和FeSO₄的吸收情况相似。我们的结果表明，已知能提高和抑制各种铁源铁生物利用率的饮食因素，对SFP中铁生物利用率的影响方向相似。然而，铁吸收抑制剂对SFP中铁的影响程度似乎比对铁盐（如FeSO₄和FeCl₃）的影响要小。这支持了SFP是食品强化和膳食补充剂中一种有前景的铁源这一假设。
