The Effects of Curcuminoids Supplementation on Serum Adipokines: An Umbrella Review of Meta-Analyses of Randomized Controlled Trials

This umbrella review of randomized clinical trials aims to provide a unique and detailed understanding of curcumin's effects on adipokines, adding a novel perspective to the existing body of research. We carried out a thorough search of international databases up to April 2024, including MEDLINE, SciVerse Scopus, and Clarivate Analytics Web of Science. A random-effects model was utilized to evaluate the impact of curcuminoid on adipokines. The umbrella review incorporated meta-analyses that examined the effects of curcuminoid supplementation on adipokines, presenting associated effect sizes (ES) and confidence intervals (CI). We applied the GRADE and AMSTAR (A Tool for Assessing the Risk of Bias in Systematic Reviews system) to assess the certainty of the evidence and the quality of the systematic reviews. Our analysis of one meta-analysis, including 14 RCTs plus 1 RCT not included in meta-analyses, revealed significant and impactful findings. We found a substantial increase in serum adiponectin levels with curcuminoid supplementation, indicating a positive effect (SMD: 0.9; 95% CI, 0.4 to 1.3, p < 0.001; I-2 = 92.2%). However, we did not observe a significant impact on serum leptin. The GRADE assessment supports the effect of curcuminoids on adiponectin with moderate evidence, while the impact on leptin was supported by low evidence. Curcuminoid supplementation significantly increases serum adiponectin levels with moderate-quality evidence and has no significant impact on serum leptin. This provides evidence as to the safety and effectiveness of curcuminoids in enhancing adiponectin without adverse effects, reassuring the audience about their potential in adipokine research.