The effect of resveratrol (RV) intake has been reviewed in several studies performed in humans with different health status. The purpose of this review is to summarize the results of clinical trials of the last decade, in which RV was determined in biological samples such as human plasma, urine, and feces. The topics covered include RV bioavailability, pharmacokinetics, effects on cardiovascular diseases, cognitive diseases, cancer, type 2 diabetes (T2D), oxidative stress, and inflammation states. The overview of the recent research reveals a clear tendency to identify RV in plasma, showing that its supplementation is safe. Furthermore, RV bioavailability depends on several factors such as dose, associated food matrix, or time of ingestion. Notably, enterohepatic recirculation of RV has been observed, and RV is largely excreted in the urine within the first four hours after consumption. Much of the research on RV in the last 10 years has focused on its effects on pathologies related to oxidative stress, inflammatory biomarkers, T2D, cardiovascular diseases, and neurological diseases.

The role of gut microbiota in human health has been investigated extensively in recent years. The association of dysbiosis, detrimental changes in the colonic population, with several health conditions has led to the development of pro-, pre- and symbiotic foods. If not absorbed in the small intestine or secreted in bile, polyphenols and other food components can reach the large intestine where they are susceptible to modification by the microbial population, resulting in molecules with potentially beneficial health effects. This review provides an overview of studies that have detected and/or quantified microbial phenolic metabolites using high-performance liquid chromatography as the separation technique, followed by detection through mass spectrometry. Both in vitro experimental studies and human clinical trials are covered. Although many of the microbial phenolic metabolites MPM) reported in in vitro studies were identified in human samples, further research is needed to associate them with clinical health outcomes.