The Effects of Nano-Curcumin Supplementation on Risk Factors for Cardiovascular Disease: A GRADE-Assessed Systematic Review and Meta-Analysis of Clinical Trials

Background: Previous studies have indicated that curcumin supplementation may be beneficial for cardiometabolic health; however, current evidence regarding the effects of its nanorange formulations, popularly known as “nano-curcumin”, remains unclear. This systematic review and meta-analysis aimed to determine the impact of nano-curcumin supplementation on risk factors for cardiovascular disease. Methods: PubMed, Scopus, Embase, and ISI web of science were systematically searched up to May 2021 using relevant keywords. All randomized controlled trials (RCTs) investigating the effects of nano-curcumin supplementation on cardiovascular disease risk factors were included. Meta-analysis was performed using random-effects models, and subgroup analysis was performed to explore variations by dose and baseline risk profiles. Results: According to the results of this study, nano-curcumin supplementation was associated with improvements in the glycemic profile by decreasing fasting blood glucose (FBG) (WMD: −18.14 mg/dL; 95% CI: −29.31 to −6.97; p = 0.001), insulin (WMD: −1.21 mg/dL; 95% CI: −1.43 to −1.00; p < 0.001), and HOMA-IR (WMD: −0.28 mg/dL; 95% CI: −0.33 to −0.23; p < 0.001). Interestingly, nano-curcumin supplementation resulted in increases in high-density lipoprotein (HDL) (WMD: 5.77 mg/dL; 95% CI: 2.90 to 8.64; p < 0.001). In terms of other lipid profile markers (triglyceride (TG), total cholesterol (TC), and low-density lipoprotein (LDL)), subgroup analyses showed that nano-curcumin supplementation had more favorable effects on lipid profiles in individuals with dyslipidemia at baseline. Nano-curcumin supplementation also showed favorable anti-inflammatory effects by decreasing C-reactive protein (CRP) (WMD: −1.29 mg/L; 95% CI: −2.15 to −0.44; p = 0.003) and interleukin-6 (IL-6) (WMD: −2.78 mg/dL; 95% CI: −3.76 to −1.79; p< 0.001). Moreover, our results showed the hypotensive effect of nano-curcumin, evidenced by a decrease in systolic blood pressure (SBP). Conclusions: In conclusion, our meta-analysis suggests that nano-curcumin supplementation may decline cardiovascular disease risk by improving glycemic and lipid profiles, inflammation, and SBP. Future large-scale investigations with longer durations are needed to expand on our findings.