Inulin and Mucins in the Intestine can reduce Iron uptake from dissociable suplements

Abstract

Prebiotics such as inulin have been suggested to have an enhancing effect on iron absorption. However, dietary soluble fiber have mineral binding capacities (1). In addition, mucus production in the intestine constitutes a diffussion barrier to ions. This study evaluates the effects of inulin and mucins on iron uptake. FeSO4 and FeEDTA solutions (12 μM as iron), with or without inulin, were subjected to an in vitro digestion/cell culture model (2). The in vitro effects of inulin on the fluxes of Fe (FFe) were evaluated. Cultures of two human intestinal cell lines, independent Caco-2 or within HT29-MTX mucin-secreting cells (75:25) were used as intestinal epitelia model. Cell ferritin formation was used to measure iron uptake. Inulin decreased FFe only from FeSO4 solution suggesting a mineral binding effect. The presence of HT29-MTX cells abolished completely iron uptake from FeSO4, and reduced (up to 42%) iron uptake from FeEDTA solutions. In the latter solutions, inulin did not affect iron uptake. These results indicate that inulin may exhibits a mineral binding effect on dissociable iron, thereby lowering its diffusion towards the brush membrane which might impair iron absorption in the upper intestine. Cocultures of the two intestinal cell lines could be a physiological approach to in vivo situation.