The Effects of Pomegranate Supplementation on Biomarkers of Inflammation and Endothelial Dysfunction: A Meta-Analysis and Systematic Review

Abstract Objects Cardiovascular disease (CVD) is one of the leading causes of death worldwide. CVD is associated with increased levels of reactive oxygen species which are pro-inflammatory and can damage the endothelium. The pomegranate fruit is a rich source of phytochemicals with a high antioxidant and anti-inflammatory activity, possessing thus health benefits. This systematic review and meta-analysis aims to evaluate the effect of pomegranate juice on the biomarkers of inflammation and vascular dysfunction. Methods Studies were identified using the PubMed/Medline and SCOPUS databases. Screening of relevant articles and references was carried out from inception until May 2019. This systematic review and meta-analysis was performed using the Preferred Items for Reporting of Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Results Overall, 16 randomized controlled trials (RCTs) involving 572 subjects were included in this study. Combining effect sizes from 16 studies, we recorded that pomegranate supplementation significantly reduced hs-CRP, IL-6 and TNF-α (Weighted Mean Differences (WMD): -6.57 mg/L, 95% CI: -10.04 to -3.10, P = 0.000; WMD: −1.68 pg/mL, 95% CI: −3.52, 0.157, P = 0.000; WMD: −2.37 pg/mL, 95% CI: -3.67, -1.07, P = 0.00, respectively) levels, when compared to placebo. No significant reduction was found in CRP (WMD: 2.19 mg/dL, 95% CI: −3.28, 7.67, P = 0.61), E-selectin (WMD: 8.42 ng/mL, 95% CI: −22.9, 39.8, P = 0.599), ICAM (WMD= -17.38 ng/mL, 95% CI: -53.43, 18.66, P = 0.107), VCAM (WMD: -69.32 ng/mL, 95% CI: -229.26, 90.61, P = 0.396) or MDA (WMD: 0.031 μmol/L, 95% CI: −1.56, 0.218, P = 0.746) comparing pomegranate supplementation to placebo. Conclusion We found a significant effect of pomegranate supplementation on hs-CRP, IL-6 and TNF-α in adults. However, the effects of pomegranate supplementation on CRP, E-selectin, ICAM, VCAM or MDA were not significant in this meta-analysis.