Meat and ascorbic acid can promote Fe availability from Fe-phytate but not from Fe-tannic acid complexes.
This study utilized an in vitro digestion/Caco-2 cell model to determine the levels of ascorbic acid (AA) and "meat factor" needed to promote Fe absorption from Fe complexed with phytic acid (PA) or tannic acid (TA). AA reversed the inhibition of Fe absorption by PA beginning at a molar ratio of 1:20:1 (Fe:PA:AA) but essentially had no effect on the Fe complexed with TA. Fish also reversed the inhibition of Fe uptake by PA but not by TA. TA and fish decreased total Fe solubility. Iron in the presence of PA was highly soluble. AA, but not fish, increased the percentage of soluble Fe as Fe2+ in the presence of both inhibitors. The results indicate that monoferric phytate is a form of Fe that can be available for absorption in the presence of uptake promoters. In contrast, a TA-Fe complex is much less soluble and unavailable in the presence of promoters.
Engle-Stone
Reina
R
U.S. Plant, Soil, and Nutrition Laboratory, Agricultural Research Service, U.S. Department of Agriculture, Tower Road, Ithaca, New York 14853, USA.
Yeung
Andrew
A
Welch
Ross
R
Glahn
Raymond
R
D001205:Ascorbic Acid / Q000494:pharmacology*; D001682:Biological Availability; D018938:Caco-2 Cells; D004032:Diet; D006801:Humans; D007501:Iron / Q000378:metabolism*; D008460:Meat / Q000032:analysis*; D010084:Oxidation-Reduction; D010833:Phytic Acid / Q000378:metabolism*; D012995:Solubility; D013634:Tannins / Q000378:metabolism*; D014815:Vitamins / Q000494:pharmacology*
D013634:Tannins; D014815:Vitamins; D010833:Phytic Acid; D007501:Iron; D001205:Ascorbic Acid