Effects of curcumin on serum cytokine concentrations in subjects with metabolic syndrome: A post-hoc analysis of a randomized controlled trial

Background: Cytokines are involved in the development of metabolic abnormalities that may result in metabolic syndrome (MetS). Since curcumin has shown anti-inflammatory properties, the aim of this study was to evaluate the effect of curcumin supplementation on serum cytokines concentrations in subjects with MetS. Methods: This study was a post-hoc analysis of a randomized controlled trial in which males and females with diagnosis of MetS, according to the criteria defined by the National Cholesterol Education Program Adult Treatment Panel III guidelines, were studied. Subjects who met the inclusion criteria were randomly assigned to either curcumin (daily dose of 1 g/day) or a matched placebo for a period of 8 weeks. Results: One hundred and seventeen subjects were assigned to either curcumin (n = 59) or placebo (n = 58) groups. Within-group analysis revealed significant reductions in serum concentrations of TNF-alpha, IL-6, TGF-beta and MCP-1 following curcumin supplementation (p < 0.001). In the placebo group, serum levels of TGF-beta were decreased (p = 0.003) but those of IL-6 (p = 0.735), TNF-alpha (p = 0.138) and MCP-1 (p = 0.832) remained unaltered by the end of study. Between-group comparison suggested significantly greater reductions in serum concentrations of TNF-a, IL-6, TGF-b and MCP-1 in the curcumin versus placebo group (p < 0.001). Apart from IL-6, changes in other parameters remained statistically significant after adjustment for potential confounders including changes in serum lipids and glucose levels, and baseline serum concentration of the cytokines. Conclusion: Results of the present study suggest that curcumin supplementation significantly decreases serum concentrations of pro-inflammatory cytokines in subjects with MetS. ((C) Elsevier Masson SAS. All rights reserved.