Sahar Foshati - Department of Clinical Nutrition, School of Nutrition and Food Sciences, Isfahan University of Medical Sciences, Isfahan, Iran
Reza Amani - Department of Clinical Nutrition, School of Nutrition and Food Sciences, Isfahan University of Medical Sciences, Isfahan, Iran
Mohammad Hossein Rouhani - Department of Community Nutrition, School of Nutrition and Food Sciences, Isfahan University of Medical Sciences, Isfahan, Iran

Introduction: Several studies have shown that grape seed extract (GSE) supplementation can reduce inflammation and oxidative stress, but their results seem irreproducible. The objective of this systematic review and meta-analysis was to determine the effect of GSE supplementation on high-sensitivity C-reactive protein (hs-CRP) and white blood cell count (WBC) as inflammatory biomarkers and total antioxidant capacity (TAC), oxidized low-density lipoprotein (ox-LDL), and malondialdehyde (MDA) as biomarkers of oxidative stress.Methods: We systematically searched PubMed, Scopus, Google Scholar, and Web of Science databases until September 2019. Two independent authors performed article selection and data extraction. The Cochrane Collaboration Risk of Bias Assessment Tool was used for quality assessment of studies. Pooled weighted mean differences with 95% confidence intervals were calculated using a random-effects model. I-squared was used to quantify the extent of heterogeneity. Subgroup analyses were conducted in case of significant statistical heterogeneity. Sensitivity analysis and publication bias were also assessed.Results: Twenty-two clinical trials were included in the systematic review, and seventeen clinical trials were included in the meta-analysis. GSE supplementation significantly decreased blood levels of ox-LDL (-0.44; 95% CI: -0.72, -0.15) and MDA (-1.40; 95% CI: -2.24, -0.56) but did not significantly influence blood levels of TAC (0.40; 95% CI: -0.07, 0.88), hs-CRP (-0.34; 95% CI: -0.88, 0.20), and WBC (0.16; 95% CI: -0.22, 0.54).Conclusions: GSE supplementation can reduce blood levels of lipid peroxidation biomarkers such as ox-LDL and MDA. More high-quality studies are needed to determine the effect of GSE supplementation on TAC, hs-CRP, and WBC.

Malondialdehyde, Oxidized low density lipoprotein, Vitis vinifera