Polyphenols and health: Moving beyond antioxidants

Diets in which plant foods, including berries, provide a relevant portion of caloric intake are associated with a reduced risk of certain degenerative diseases like cancer and atherosclerosis. As known, vegetables and fruits such as berries are rich in polyphenols, which are products of secondary metabolism. In the past few years, research on polyphenols has remarkably expanded and is constantly reporting interesting biological activities of these compounds. Due to the participation of oxidative processes in the onset and development of degenerative diseases, much attention has been paid to the antioxidant properties of polyphenols. Alas, the discovery of their low bioavailability - especially when compared to the concentrations of endogenous antioxidants - is questioning the actions of polyphenols as mere antioxidants. In this review we critically discuss the current limitations of polyphenol research and we contend that, in addition to their putative antioxidant action, several biochemical and physiological processes might be influenced by polyphenols.