The effects of capsinoids and fermented red pepper paste supplementation on Glycaemic Control: A systematic review and meta‐analysis of randomised controlled trials

Objective The present systematic review and meta‐analysis were conducted to investigate the effects of capsinoids supplementation on glycaemic control. Methods Relevant studies, published up to May 2020, were searched through PubMed/Medline, Scopus, ISI Web of Science, Embase and Google Scholar. All randomised clinical trials investigating the effect of capsinoids supplementation on glycaemic control were included. Results Of 326 citations, eight trials with nine effect sizes that enrolled 530 subjects were included. Capsinoids and red pepper resulted in no significant reduction in glucose (Weighted mean differences (WMD): −0.27 mg/dL; 95% CI: −1.9 to 1.37, P = .75), insulin (WMD: −0.09 µU/mL; 95% CI: −1.76 to 1.57, P = .913), homeostatic model assessment for insulin resistance (HOMA‐IR) (WMD: 0.52; 95% CI: −0.29 to 1.32, P = .208) and haemoglobin A1C (HbA1C) (WMD: 0.01%; 95% CI: −0.04 to 0.05, P = .712). Greater effects on glucose were detected in trials performed on both gender, using red pepper, lasted ≥12 weeks, and participants aged >40 years old and recruited greater sample size >50. Insulin and HOMA‐IR were reduced by using red pepper. Conclusion Overall, these data suggest that capsinoids and red pepper supplementation did not have beneficial effects on glucose, insulin, HbA1C and HOMA‐IR but significantly reduce glucose in people older than 40 years.