Less than 10% of polyphenols are absorbed in the small intestine, with the vast majority moving into the colon. The potential for polyphenols to have a direct effect on metabolism is therefore low; scientists think that gut bacterial activity changes the structure of polyphenols, turning them into potent active substances with new functions. At the same time, scientists have discovered that polyphenols also have an effect on gut bacteria. Phenols produced by gut bacteria are the root cause of diseases including uremia, diabetes, and diabetic kidney disease, but scientists say polyphenols can regulate them. Attention is now focusing on the interaction between polyphenols and gut microbes.