Effect of the Starchy Legume Source on the In Vitro Fermentation of the Fecal Microbiota from Normal-Weight and Obese Individuals.

The relationship between the gut microbiota (GM) and the health of human beings has been a topic of growing interest in the last few years. Legumes are a rich source of indigestible carbohydrates, including resistant starch (RS), which are substrates of the GM. The aim of this study was to evaluate the effect of the indigestible fraction of legumes on the fecal microbiota of normal-weight (NW) and obese (O) donors. Accordingly, a preclinical in vitro fermentation model was developed (Goñi and Martín-Carrón, Nutr Res 18:1077-1089, 1998). Short-chain fatty acid (SCFAs) production was measured via gas chromatography. In addition, the fecal microbiota was characterized via 16 S rRNA sequence analysis. The results revealed that the ratio of the relative abundance of Firmicutes to Bacteroidetes was lower in O individuals than in NW individuals. Bacteroides was the predominant genus in the fecal inoculum of the O group. Total SCFAs production was significantly greater in the chickpea (C) group than in the lentil (L) and white bean (WB) groups among the samples from the NW group. In contrast, WB presented the highest production of SCFAs in the samples from the O group. These results suggest that fermentation products (SCFAs) are determined by the components of the legumes, including RS, and the type of microbiota donor (NW or O individuals).