Effect of curcumin on circulating interleukin-6 concentrations: A systematic review and meta-analysis of randomized controlled trials

The aim of this meta-analysis was to evaluate the efficacy of curcuminoids supplementation on circulating concentrations of IL-6 in randomized controlled trials (RCTs). The search included PubMed-Medline, Scopus, Web of Science and Google Scholar databases by up to November 01, 2015, to identify RCTs investigating the impact of curcuminoids on circulating IL-6 concentrations. Nine RCTs comprising 10 treatment arms were found to be eligible for the meta-analysis. There was a significant reduction of circulating IL-6 concentrations following curcuminoids supplementation (WMD: -0.60 pg/mL, 95% CI: -1.06, -0.14, p = 0.011). Meta-regression did not suggest any significant association between the circulating IL-6 lowering effects of curcuminoids with either dose or duration of treatment. There was a significant association between the IL-6-lowering activity of curcumin and baseline IL-6 concentration (slope: -0.51; 95% CI: -0.80, -0.23; p = 0.005). This meta-analysis of RCTs suggested a significant effect of curcumin in lowering circulating IL-6 concentrations. This effect appears to be more evident in patients with higher degrees of systemic inflammation. (C) 2016 Elsevier Ltd. All rights reserved.