The effect of Capsaicinoids or Capsinoids in red pepper on thermogenesis in healthy adults: A systematic review and meta‐analysis
Pardis Irandoost, Neda Lotfi Yagin, Nazli Namazi, Abbasali Keshtkar, Farnaz Farsi, Naimeh Mesri Alamdari, Mohammadreza Vafa
Abstract
The outcomes of the earlier trials are controversial concerning the effect of Capsaicinoids/Capsinoids on thermogenesis. We carried out this systematic review and meta‐analysis to examine the effect of Capsaicinoids/Capsinoids on thermogenesis indices including resting metabolic rate (RMR) and respiratory quotient (RQ) in healthy adults. An electronic literature search was conducted between 1990 and 2019, using the following databases: PubMed, Web of Sciences, Scopus, Cochrane Central Register of Controlled Trials, and EMBASE. Placebo‐controlled clinical trials were considered as eligible papers. Effect sizes were pooled using weighted mean difference (WMD), with a random‐effects model. Of the 4,092 articles, 13 studies were included in the meta‐analysis. Pooled effect sizes revealed that compared with placebo, Capsaicinoids/Capsinoids significantly increased RMR (WMD: 33.99 Kcal/day, 95% CI: 15.95, 52.03; I 2 : 0%, p = .94), energy expenditure, and fat oxidation. It also significantly lessened RQ (WMD: −0.01, 95% CI: −0.02, −0.01; I 2 : 5.4%, p = .39) and carbohydrate oxidation. Moreover, intervention in capsule form for longer duration had a more considerable influence on RMR than comparative groups. We observed moderate improvement in RMR, RQ, and fat oxidation following supplementation with Capsaicinoids/Capsinoids. However, further high‐quality studies are required to clarify the thermogenic properties of Capsaicinoids/Capsinoids.