45I-13 |
Iron bioavailability from fortified wheat bran cereal and bread assessed with an in vitro digestion/Caco-2 cell culture model: Effects of raisins |
C. K. YEUNG1, R. P. Glahn2, and D. D. Miller1. (1) Dept. of Food Science, Cornell Univ., 216 Stocking Hall, Ithaca, NY 14853-7201, (2) Soil-Crops-Human Nutrition Unit, USDA-ARS-U.S. Plant, Soil & Nutrition Lab., Tower Rd., Ithaca, NY 14853-2901 Raisins contain high levels of phenolic compounds which are known inhibitors of iron absorption. We showed that these compounds inhibit the bioavailability of intrinsic raisin iron but their effects on the bioavailability of iron from other foods consumed in the same meal with raisins have not been studied. The objective of this study was therefore to assess the effects of raisins on iron bioavailability from wheat bran cereal (WBC) and bread fortified with selected iron fortificants. Samples of WBC, WBC with skim milk (WBC+M), and bread, unfortified or fortified with elemental iron, ferrous sulfate or sodium iron ethylenediaminetetraacetate (NaFeEDTA) at 9mg iron/serving, were prepared. Raisins, when added, were at 25% w/w. Iron bioavailability from the food samples was assessed with an in vitro digestion/Caco-2 cell culture model. Samples were subjected to a two-step simulated gastrointestinal digestion process. Ferritin formation in Caco-2 cells exposed to the digests was used as an index of iron bioavailability. In general, there were significant differences in iron bioavailability between samples with and without added raisins (p<0.01). Raisins reduced iron bioavailability by 34% - 86% in unfortified and elemental iron-fortified samples. For samples fortified with ferrous sulfate, raisins reduced iron bioavailability by 50% and 55% in WBC+M and bread respectively, but had no inhibitory effect in WBC. For all samples fortified with NaFeEDTA, reductions were only 8% - 24%. Iron bioavailability was also markedly higher (>5-fold) for samples fortified with NaFeEDTA than with the other two fortificants (p<0.01). Our results suggest that raisins inhibit iron bioavailability from unfortified raisin-containing foods, as well as foods fortified with elemental iron or ferrous sulfate, but this inhibitory effect is much less pronounced in foods fortified with NaFeEDTA. In addition, iron in the form of NaFeEDTA is more bioavailable than elemental iron and ferrous sulfate in raisin-containing foods.
Session 45I, Nutrition: General
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