Resveratrol supplementation and plasma adipokines concentrations? A systematic review and meta-analysis of randomized controlled trials.

The results of human clinical trials have revealed that the effects of resveratrol on adipokines are inconsistent. Our objective was to elucidate the role of resveratrol supplementation on adipokines through a systematic review and a meta-analysis of available randomized placebo-controlled trials (RCTs). The search included PubMed-MEDLINE, SCOPUS and ISI web of sciences database till up to 6th November 2016. Weight mean differences (WMD) were calculated for net changes in adipokines using fixed-effects or random-effects models; meta-regression analysis and publication bias were conducted in accordance with standard methods. Nine RCTs with 11 treatment arms were eligible for inclusion in this systematic review and meta-analysis. Meta-analysis of data from 10 treatment arms showed a significant change in plasma adiponectin concentrations following resveratrol supplementation (WMD: 1.10μg/ml, 95%CI: 0.88, 1.33, p<0.001); Q=11.43, I=21.29%, p=0.247). There was a significant greater adiponectin-reducing effect in trials with higher than or equal to 100mg/day (WMD: 1.11μg/ml, 95%CI: 0.88, 1.34, p<0.001), versus those with less than 100 mg/day dosage (WMD: 0.84μg/ml, 95%CI: -0.62, 2.31, p=0.260). Meta-analysis of data from 5 treatment arms did not find any significant change in plasma leptin concentrations following resveratrol supplementation (WMD: 3.77ng/ml, 95% CI: -2.28, 9.83, p=0.222; Q=8.00, I=50.01%). Resveratrol significantly improves adiponectin but does not affect leptin concentrations. Additional studies are required to further evaluate the potential benefits of resveratrol on adipokines in humans.