Resveratrol supplementation and type 2 diabetes: a systematic review and meta-analysis.

This study aimed to review the literature on studies that evaluated resveratrol's effects supplementation on parameters of diabetes in humans. We conducted an online search in the following databases: Pubmed, Lilacs, Scielo, Scopus, Web of Science, Embase, and Cochrane. It included experimental studies that investigated the effects of resveratrol supplementation for diabetes treatment or prevention and its relationship with fasting blood glucose, insulin resistance, and glycated hemoglobin. Observational, non-human studies and non-randomized clinical trials were excluded. We conducted a meta-analysis to evaluate the effects of resveratrol supplementation on fasting blood glucose, insulin resistance, and glycated hemoglobin. Thirty studies were included in the review. Almost 60% demonstrated at least one significant effect of the resveratrol supplementation related to diabetes. In the meta-analysis, there was a significant effect on the reduction of insulin resistance [SMD: -0.34; CI 95%: -0.64, -0.04;  = 0.01; I = 70%] and glycated hemoglobin [SMD: -0.64; CI 95%: -1.22, -0.07;  = 0.01; I = 90%]. For fasting blood glucose, the results were significant only for individuals with diabetes [SMD: -0.85; CI 95%: -1.49, -0.21;  = 0.01; I = 90%]. This systematic review with meta-analysis demonstrated that resveratrol supplementation has protective effects on diabetes parameters.