(Poly)phenols and dietary fiber in beans: Metabolism and nutritional impact in the gastrointestinal tract

A daily diet including common beans (Phaseolus vulgaris L.) has been linked to numerous health benefits due to their rich nutritional profile. Beans contain high levels of dietary fiber and (poly)phenols (flavonoids, phenolic acids and tannins), which are pivotal in promoting health. This manuscript critically reviews the gut metabolism of (poly)phenols and dietary fiber found in beans in relation to the proposed health benefits based on the in vitro and in vivo evidence. After oral consumption, certain (poly)phenols inhibit digestive enzymes in the small intestine, potentially lowering postprandial glycemic responses. Dietary fiber and many (poly)phenols pass to the colon and are metabolized by the microbiota. Phenolic metabolites and fiber-derived short-chain fatty acids (SCFA) modulate microbiota composition and other health biomarkers. The observed benefits of whole beans are primarily attributed to the phenolic metabolites and SCFA. Further research should focus on profiling metabolites from their parent compounds to better understand their metabolic fate and biological activity, spanning from the gastrointestinal tract to the systemic circulation.