The effects of curcumin-containing supplements on biomarkers of inflammation and oxidative stress: A systematic review and meta-analysis of randomized controlled trials

Besides other benefits, curcumin is getting more recognized for its antioxidant and anti-inflammatory properties, highlighting the importance of curcumin application for chronic disease prevention. This systematic review and meta-analysis of randomized controlled trials (RCTs) was conducted to assess the influence of curcumin-containing supplements on biomarkers of inflammation and oxidative stress. MEDLINE, EMBASE, Web of Science, and Cochrane Central Register of Controlled Trials were searched till January 2018 for eligible studies. The selected studies were evaluated for their quality using the Cochrane risk of bias tool and relevant data were extracted from included studies. Data were pooled using the inverse variance method and expressed as standardized mean difference (SMD) with 95% confidence intervals (95% CI). Fifteen RCTs were included in the final analysis. The meta-analysis indicated that curcumin supplementation significantly decreased interleukin 6 (IL-6) (SMD -2.08; 95% CI [-3.90, -0.25]; p = 0.02), high-sensitivity C-reactive protein (hs-CRP) (SMD -0.65; 95% CI [-1.20, -0.10], p = 0.02), and malondialdehyde (MDA) concentrations (SMD -3.14; 95% CI [-4.76, -1.53], p < 0.001). Though, curcumin supplementation had no significant effect on tumor necrosis factor-alpha (SMD -1.62; 95% CI [-3.60, 0.36]; p = 0.10) and superoxide dismutase levels (SMD 0.34; 95% CI [-1.06, 1.74], p = 0.63). Overall, this meta-analysis suggests that taking curcumin-containing supplements may exert anti-inflammatory and antioxidant properties through a significant reduction in IL-6, hs-CRP, and MDA levels.