Human bioavailability of resveratrol from moderate consumption of red wine

Background and aims: Epidemiology associates moderate consumption of red wine with reduced risk of CVD. The pleiotropic biological properties of resveratrol at pharmacological doses were demonstrated in vitro and animal studies. The aim of this study was to clarify human bioavailability of resveratrol from a moderate consumption of red wine. Methods and results: 25 healthy subjects were enrolled and three experimental conditions were applied: consumption of red wine at fasting or associated to a standard meal or to meals with different fat content. Free-, 3-glucuronide- and 4’-glucuronide- resveratrol in serum samples, over 4h from wine consumption, were quantified. Free trans-resveratrol was found, in trace amounts, only in some serum samples collected after 30 min from wine ingestion while resveratrol-glucuronides predominated at following times. Trans-resveratrol bioavailability was independent from the meal or its fat content. Conclusions: Our data and the recent findings from human studies, indicating the major role of metabolites from in vivo bio-conversion and microflora activity (rather than parental compounds) to exert health benefits of dietary polyphenols, suggest that the whole antioxidant pool of red wine and the baseline plasma increase of their metabolites may better explain epidemiological evidence than the sole resveratrol. Further human long-term studies are warranted.