The effects of resveratrol on lipid profiles and liver enzymes in patients with metabolic syndrome and related disorders: a systematic review and meta-analysis of randomized controlled trials

Background There are current trials investigating the effect of resveratrol supplementation on lipid profiles and liver enzymes among patients with metabolic syndrome (MetS) and related disorders; however, their findings are controversial. This systematic review and meta-analysis were aimed to determine the effects of resveratrol supplementation on lipid profiles and liver enzymes among patients with MetS and related disorders. Methods We performed a comprehensive search of the following online databases up to November 2018: Cochrane Library, PubMed, Embase, and Web of Science. The relevant articles were assessed for quality of studies using the Cochrane risk of bias tool. Results Out of 2459 citations, 31 articles were appropriate for including to the current meta-analysis. The pooled results indicated that resveratrol use significantly decreased total cholesterol [weighted mean difference (WMD) = - 7.65 mg/dL; 95% CI, - 12.93, - 2.37; P < 0.01; I-2: 83.4%] and increased gamma-glutamyl transferase (GGT) concentrations (WMD = 1.76 U/l; 95% CI, 0.58, 2.94; P < 0.01; I-2: 20.1%). We found no significant effect of resveratrol supplementation on triglycerides (WMD = - 5.84 mg/dL; 95% CI, - 12.68, 1.00; P = 0.09; I-2: 66.8%), LDL- (WMD = -2.90 mg/dL; 95% CI, - 10.88, 5.09; P = 0.47; I-2: 96.0%), HDL-cholesterol (WMD = 0.49 mg/dL; 95% CI, - 0.80, 1.78; P = 0.45; I-2: 74.0%), alanine aminotransferase (ALT) (WMD = -0.14 U/l; 95% CI, - 3.69, 3.41; P = 0.93; I-2: 79.6%), and aspartate aminotransferase (AST) (WMD = -0.34 U/l; 95% CI, - 2.94, 2.27; P = 0.80; I-2: 88.0%) concentrations. Conclusions This meta-analysis demonstrated that resveratrol supplementation among patients with MetS and related disorders significantly reduced total cholesterol and increased GGT concentrations, but did not affect triglycerides, LDL-, HDL-cholesterol, ALT, and AST concentrations. This data suggests that resveratrol may have a potential cardio-protective effect in patients with MetS and related disorders.