Digestive fate of polyphenols: updated view of the influence of chemical structure and the presence of cell wall material

The increasing awareness of lifestyle implications on our well-being resulted in a great interest in health-promoting aspects of food and food components, and their role in the prevention of chronic diseases. Polyphenols are suggested to be correlated with numerous health benefits, however, their bioaccessibility and bioavailability, which can alter their actual activity, is not fully understood. Recent studies reported various, yet usually low, structure-dependent in vitro bioaccessibility and in vivo bioavailability values, affected by the presence of food matrix. Moreover, a growing body of evidence report the formation of various metabolites by the gut microbiota, also affected by the food matrix. This review summarizes the most recent reports on polyphenols bioaccessibility and bioavailability along the digestive tract, focusing on the influence of the two main factors, the polyphenols chemical structure and the presence of cell wall material.