Interaction between Tea Polyphenols and Intestinal Microbiota in Host Metabolic Diseases from the Perspective of the Gut–Brain Axis

Tea polyphenols (TP) have shown multiple biological activities and the ability to modulate the composition and function of intestinal microbiota. Certain human metabolic diseases are engendered by the disruption of the circadian rhythm. Circadian rhythm oscillations exist in both intestinal microbiota and hypothalamus. The brain–gut-microbiome axis enables intestinal microorganisms to communicate with the brain. The close reciprocity between intestinal microbiota and circadian rhythm supplies a new opportunity for TP to regulate circadian-rhythm-related diseases relying on intestinal microbiota. Therefore, based on the potential bidirectional association of the brain and gut microbes, this review mainly discussed the interaction between TP and intestinal microbiota from the perspective of the gut–brain axis (GBA) to improve the theory of metabolic diseases prevention.