 On the contrary, research indicates that although polyphenols are antioxidants in vitro, antioxidant effects in vivo are probably negligible or absent.By non-antioxidant mechanisms still undefined, polyphenols may affect mechanisms of cardiovascular disease or cancer.The increase in antioxidant capacity of blood seen after the consumption of polyphenol-rich (ORAC-rich) foods is not caused directly by the polyphenols, but most likely results from increased uric acid levels derived from metabolism of flavonoids.