Submitted to: Food Chemistry
Publication Type: Peer reviewed journal
Publication Acceptance Date: 12/1/2007
Publication Date: 7/1/2008
Citation: Laparra, J., Tako, E., Glahn, R.P., Miller, D. 2008. Supplemental inulin does not enhance iron bioavailability to Caco-2 cells from milk- or soy-based, probiotic-containing, yogurts but incubation at 37 oC does. Food Chemistry. 109:122-128. Interpretive Summary: A model for digestion has been developed in our lab that uses a simulated digestion and Caco-2 epithelial tissue cell culture monolayer to imitate the intestinal lining and absorption of minerals into our bodies. Some studies indicate that some prebiotics such as inulin may enhance mineral absorption. This study was to see if adding inulin to yogurts containing live cultures of probiotic bacteria would affect iron absorption. The study was to see if: 1.) inulin has a direct effect on iron absorption or 2.) the bacteria may have an effect in iron absorption or 3.) the inulin will stimulate bacterial activity to effect iron absorption. Inulin did not have a direct effect on Fe bioavailabilty in the small intestine, but probiotic bacteria may play an enhancing role on Fe bioavailability.
Technical Abstract: The in vitro effects of supplemental inulin (4%) on iron (Fe) availability in two different probiotic-containing yogurts were examined. Milk or soy-based yogurts, with and without inulin, were incubated (37 deg C) or not for 48h before comparison by an in vitro gastrointestinal digestion/Caco-2 cell culture model was used to assess iron bioavailability. The dialyzable Fe fraction, cell ferritin formation, and cell associated Fe were monitored. Supplemental inulin decreased dialyzable Fe only in non-incubated milk-based yogurt. In both yogurts incubation by itself increased dialyzable Fe, and inulin increased the latter only in soy-based yogurt. Cellular ferritin concentration were higher after exposure to non-incubated milk-based than soy-based yogurt, although, after incubation the latter induced the highest ferritin formation. These data suggest that inulin does not have a direct effect on Fe bioavailabilty in the small intestine, and that probiotic bacteria play an enhancing role on Fe bioavailability.