Curcumin Preparations Can Improve Flow-Mediated Dilation and Endothelial Function: A Meta-Analysis

Introduction:Endothelial dysfunction is an early marker of atherosclerosis. Flow-mediated dilation (FMD), measured by ultrasonography, is used to noninvasively assess endothelial dysfunction. Preparations of curcumin, a naturally occurring pigment found in turmeric, may improve FMD and thus endothelial dysfunction. We did a systematic review and meta-analysis to analyze the effect of curcumin preparations on endothelial dysfunction.Methods:Five randomized clinical trials met the inclusion criteria for meta-analysis. The primary outcome was an improvement in FMD, as measured at brachial artery, after supplementations with curcumin preparations compared to the control group. Standardized mean difference and Hedges'gwere used for effect size (ES) measurement. An ES of 0.2-0.5 is considered small, 0.5-0.8 is medium, and more than 0.8 is large. Publication bias was studied too.Results:We found supplementation with curcumin preparations had an overall ES (standard difference in means) of 1.379 (95% CI 0.485-2.274,p= 0.003) on FMD. The overall Hedges'gwas 1.353 (95% CI 0.47-2.235,p= 0.03). This analysis suggests a positive and large ES of curcumin preparations on FMD using a random effect model. Smokers had a smaller increase in FMD compared to nonsmokers (ES 0.379 vs. 1.639,p= 0.034).Conclusion:This meta-analysis of 5 randomized clinical trials indicates a significant effect of curcumin preparations to increase the FMD compared to placebo and thus endothelial function. This effect is not strongly noticed in smokers.