An Integrated View of the Effects of Wine Polyphenols and Their Relevant Metabolites on Gut and Host Health

Over the last few decades, polyphenols, and flavonoids in particular, have attracted the interest of researchers, as they have been associated with the health-promoting effects derived from diets rich in vegetables and fruits, including moderate wine consumption. Recent scientific evidence suggests that wine polyphenols exert their effects through interactions with the gut microbiota, as they seem to modulate microbiota and, at the same time, are metabolized by intestinal bacteria into specific bioavailable metabolites. Microbial metabolites are better absorbed than their precursors and may be responsible for positive health activities in the digestive system (local effects) and, after being absorbed, in tissues and organs (systemic effects). Differences in gut microbiota composition and functionality among individuals can affect polyphenol activity and, therefore, their health effects. The aim of this review is to integrate the understanding of the metabolism and mechanisms of action of wine polyphenols at both local and systemic levels, underlining their impact on the gut microbiome and the inter-individual variability associated with polyphenols' metabolism and further physiological effects. The advent of promising dietary approaches linked to wine polyphenols beyond the gut microbiota community and metabolism are also discussed.