Site-specific impact of polyphenols on the gastrointestinal microbiome

The gastrointestinal (GI) tract hosts a diverse microbiota composed of trillions of microorganisms that play crucial roles in maintaining human homeostasis, health, and overall well-being. Dietary polyphenols, primarily found in edible plants, exhibit intricate interactions with the GI microbiota. These polyphenols undergo biotransformation by microbial activity and can modulate the growth of microorganisms, either promoting or inhibiting their proliferation. The composition of microbes in different segments of the GI tract is highly variable and directly influences polyphenols' metabolism. Consequently, it is essential to examine the transformation of the microbiota by dietary polyphenols. Despite their significance, the collective impact of dietary polyphenols, GI site, and GI microbiota remains an underexplored area of study, warranting further investigation. This review aims to address the existing research gap by focusing on the site-specific effects of polyphenols on the oral, esophageal, gastric, small intestinal (duodenum, jejunum, ilium), and large intestinal microbiota.