Comparison of iron uptake from reduced iron powder and FeSO4 using the Caco-2 cell model:: Effects of ascorbic acid, phytic acid, and pH

The reduced iron powder has considerable potential for use as an iron fortificant because it does not change organoleptically during storage or food preparation for cereal flour, and its bioavailability is scarcely influenced by iron absorption inhibitors in foods. The objective of this article is to study the effects of ascorbic acid, phytic acid, and pH on iron uptake from reduced iron powder (43 mu m) and FeSO4, and to compare iron bioavailability of reduced iron powders among four selected granularity levels. The cell ferritin formation is used as a marker of iron uptake. Obviously, iron uptake of reduced iron powder is increased with decreasing of powder granularity and is much lower than FeSO4 when the size is above 43 mu m, but significantly higher at 40-60 nm. In the presence of ascorbic acid or phytic acid, Caco-2 cell iron absorption from reduced iron powder (43 mu m) is significantly higher than that from FeSO4. And iron uptake of Caco-2 cells is decreased with increasing of pH from 5.5 to 7.5. Moreover, the decrease trend is more obvious for reduced iron powder than for FeSO4. Our results indicated that iron bioavailability of reduced iron powder by intestinal enterocytes is similar to that of iron salts, and reduced iron powder is more excellent than FeSO4 as food fortificant, especially at ultramicroscopic granularity.