Effect of ginger (Zingiber officinale) on inflammatory markers: A systematic review and meta-analysis of randomized controlled trials

Abstract

The aim of this systematic review and meta-analysis was to investigate the efficacy of ginger supplementation on circulating levels of C-reactive protein (CRP), high sensitivity C-reactive protein (hs-CRP), tumor necrosis factor-alpha (TNF-α), soluble intercellular adhesion molecule (sICAM), and interleukin-6 (IL-6) concentrations in randomized controlled trials (RCTs). The search included PubMed-Medline, EMBASE, Scopus, Web of Science and Cochrane Library databases to identify randomized clinical trials on the effect of ginger supplementation on circulation levels of CRP, hs-CRP, IL-6, sICAM, and TNF-α published up until February 1st, 2020. We did not restrict articles based on language of publication. Standard mean differences and 95 confidence intervals were calculated for net changes in inflammatory mediators using a random-effects model. Sixteen RCTs comprising 1010 participants were found to be eligible for this meta-analysis. There was a significant reduction of circulating CRP (SMD: −5.11, 95 CI: −7.91, −2.30, I2 = 98.1), hs-CRP (SMD: −0.88, 95 CI: −1.63, −0.12, I2 = 90.8) and TNF-α levels (SMD: −0.85, 95 CI: −1.48, −0.21, I2 = 89.4) following ginger supplementation. However, meta-analysis results did not show any significant impact of ginger supplementation on IL-6 (SMD: −0.45, 95 CI: −1.29, 0.38, I2 = 89.2), and sICAM levels (SMD: −0.05, 95 CI: −0.36, 0.26, I2 = 00.0). This systematic review and meta-analysis of RCTs demonstrates a significant impact of ginger in lowering circulating CRP, hs-CRP and TNF-α levels. Large-scale RCTs are still needed to draw concrete conclusions about the effect of ginger on other inflammatory mediators. © 2020 Elsevier Ltd