The effects of curcumin supplementation on body weight, body mass index and waist circumference: a systematic review and dose-response meta-analysis of randomized controlled trials

Background & Objectives: Inconsistent data are available about the effect of curcumin supplementation on body weight. This systematic review and meta-analysis was done to summarize data from available clinical trials on the effect of curcumin supplementation on body weight, Body Mass Index (BMI), and Waist Circumference (WC). Methods: PubMed, SCOPUS, Cochrane Library and Google Scholar were searched to find relevant articles up to August 2018. The effect sizes were expressed as weighted mean difference (WMD) and 95% confidence intervals (CI). Between-study heterogeneity was assessed using I-2. Subgroup analysis was done to find possible sources of heterogeneity. Results: Totally, 11 studies that enrolled 876 subjects (53% women) were included. Combining effect sizes suggested a significant effect of curcumin administration on body weight (Weighed Mean Difference (WMD): -1.14 kg, 95% CI: -2.16, -0.12, P = 0.02) and BMI (WMD: -0.48 kg/m2, 95% CI: -0.78, -0.17, P = 0.002), respectively. However, no significant effect of curcumin supplementation on WC was found (WMD: -1.51 cm, 95% CI: -4.041, 1.003, P = 0.23). Based on subgroup analysis, we found that the effect of curcumin on WC was significant in studies that prescribed >= 1000mg/d curcumin (P <= 0.001), those with the intervention duration of -8 weeks (P <= 0.001), and those that was performed on overweight subjects (P <= 0.001). Conclusions: We found a significant effect of curcumin supplementation on body weight and BMI, but not on WC. However, the effect of curcumin on WC was significant in studies done on overweight subjects, used >= 1000mg/d curcumin, and >= 8 weeks of duration.