Therapeutic effect of resveratrol supplementation on oxidative stress: a systematic review and meta-analysis of randomised controlled trials.

BACKGROUND: Resveratrol is a naturally occurring polyphenol compound mainly found in grapes and red wine. The evidence has suggested that resveratrol has an antioxidant effect. However, the results are inconsistent and inconclusive. Thus, we conducted a systematic review and meta-analysis to evaluate the effect of resveratrol supplementation on markers of oxidative stress.

METHODS: We searched PubMed, ISI Web of Science, EMBASE, Scopus and the Cochrane library up to December 2018 to identify randomised controlled trials (RCTs) assessing resveratrol supplementation effects on oxidative markers. Heterogeneity, publication bias, risk of bias and subgroup analysis were analysed. This meta-analysis was conducted in accordance with the guidelines of the Preferred ReportingItems for Systematic Reviews and Meta-Analysis (PRISMA).

RESULTS: Meta-analysis of data from 12 RCTs did not support significant effect of resveratrol supplementation on circulating levels of superoxide dismutase (SOD) (standardized mean difference (SMD) (1.12), (95% CI -0.91 to 3.1), p=0.28), catalase (CAT) (SMD (-0.07), (95% CI -1.4 to 1.3), p=0.92) and glutathione peroxidase (GPx) (SMD (-0.76), (95% CI -2.56 to 1.04), p=0.40). Although, resveratrol supplementation increased significantly circulating total antioxidant capacity (TAC) concentrations (SMD (0.52), (95% CI -0.02 to 1.07), p=0.05). Severe heterogeneity was observed between studies, and no obvious publication bias was observed in included RCTs.

CONCLUSION: Collectively, our findings of available RCTs did no show any benefit of resveratrol supplementation on SOD, CAT and GPx except for TAC. Well-designed RCTs are necessary to confirm these results.