Profiling Inflammatory Biomarkers following Curcumin Supplementation: An Umbrella Meta-Analysis of Randomized Clinical Trials

Objective. Several meta-analyses have shown that curcumin can reduce inflammatory biomarkers, but the findings are inconsistent. The objective of the present umbrella meta-analysis was to provide a more accurate estimate of the overall effects of curcumin on inflammatory biomarkers. Methods. The following international databases were systematically searched until March 20, 2022: PubMed, Scopus, Embase, Web of Science, and Google Scholar. A random-effects model was applied to evaluate the effects of curcumin on inflammatory biomarkers. Meta-analysis studies investigating the effects of curcumin supplementation on inflammatory biomarkers with corresponding effect sizes (ES) and confidence intervals (CI) were included in the umbrella meta-analysis. GRADE (Grading of Recommendations Assessment, Development, and Evaluation) was used to evaluate the certainty of evidence. Results. A meta-analyses of ten studies with 5,870 participants indicated a significant decrease in C-reactive protein (CRP) (ES = −0.74; 95% CI: −1.11, −0.37, p<0.001; I2 = 62.1%, p=0.015), interleukin 6 (IL-6) (ES = −1.07; 95% CI: −1.71, −0.44, p<0.001; I2 = 75.6%, p<0.001), and tumour necrosis factor α (TNF-α) levels (ES: −1.92, 95% CI: −2.64, −1.19, p<0.0; I2 = 18.1%, p=0.296) following curcumin supplementation. Greater effects on CRP and TNF-α were evident in trials with a mean age >45 years and a sample size >300 participants. Conclusion. The umbrella of meta-analysis suggests curcumin as a promising agent in reducing inflammation as an adjunctive therapeutic approach in diseases whose pathogenesis is related to a higher level of inflammatory biomarkers.