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 microbiota 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, which are substrates of the microbiota. The aim of this study was to evaluate the effect of the indigestible fraction of legumes on the fecal microbiota of normal-weight and obese donors. Accordingly, a preclinical in vitro fermentation model was developed [1]. Short-chain fatty acid (SCFA) production was measured via gas chromatography. In addition, the fecal microbiota was characterized via 16S rRNA sequence analysis. The results revealed that the ratio of the relative abundance of Firmicutes to Bacteroidetes was lower in obese individuals than in normal-weight individuals. Bacteroides was the predominant genus in the fecal inoculum of the obese group. Total SCFA production was significantly greater in the chickpea group than in the lentil and white bean groups among the samples from the normal-weight group. In contrast, white beans presented the highest production of SCFAs in the samples from the obese group. These results suggest that fermentation products (SCFAs) are determined by the components of the legumes, including resistant starches, and the type of microbiota donor (normal-weight or obese individuals).