Assessing potential effects of inulin and probiotic bacteria on Fe availability from common beans (Phaseolus vulgaris L.) to Caco-2 cells.

Inulin, a prebiotic, may enhance intestinal Fe absorption. Our objective was to assess the effects of supplemental inulin and 2 probiotic bacteria (B. infantis and L. acidophillus) on Fe availability to Caco-2 cells from common white and red beans (Phaseolus vulgaris L.). Cooked beans were mixed or not with supplemental inulin (4%, w/w), and then subjected to simulated gastrointestinal digestion (pepsin, pH 2; pancreatin, pH 7.2). Subsequently, the digests were incubated overnight with and without B. infantis or L. acidophilus. Ferritin formation in Caco-2 cells was used to evaluate Fe uptake. Total soluble phenols (Folin-Ciocalteau) and phytate (HPLC-electrochemical detection) were quantified, and the flavonoids profile (HPLC-PDA/UV detection) was monitored in the digests. Supplemental inulin did not affect Fe uptake from white nor red beans. Incubation with B. infantis increased total soluble phenols (TSP) in the digests and decreased Fe uptake. Incubation with L. acidophilus decreased TSP in the digest and increased Fe uptake. Variations in Fe uptake were not associated with soluble phytate concentrations in the digests. The largest change in flavonoids profile were found in the digests incubated with L. acidophilus, which decreased the soluble concentration of astragalin (kaempferol-3-O-glucoside). These results suggest that certain probiotics could increase Fe uptake from common beans.