Hydrolytic polyphenol-utilizing proteins (PUPs), particularly beta-glucosidase and alpha-L-rhamnosidase, are among the most prevalent and abundant microbial genes in the human gut microbiome and are consistently associated with dietary polyphenol intake, indicating a core functional capacity for breaking down glycosidic bonds in plant compounds.

When people eat plant foods rich in polyphenols, these compounds travel to the gut unchanged. Bacteria in the gut that have genes for enzymes like beta-glucosidase and alpha-L-rhamnosidase break apart the sugar attachments on polyphenols, freeing the active parts. This gives those bacteria an energy advantage, so they grow more and become more common. The more varied the polyphenols in the diet, the more types of these enzymes are needed, leading to a wider variety of bacteria with different enzyme genes.