Dietary supplementation of transient receptor potential vanilloid-1 channel agonists reduces serum total cholesterol level: a meta-analysis of controlled human trials

Systematic review and meta-analysis of 10 controlled human trials involving 199 participants in active intervention arms. The trials enrolled adults from multiple countries, mostly generally healthy participants, with one study including people with postprandial diabetes mellitus.

Dietary capsaicinoid supplementation, including capsaicin-containing preparations, was tested across 10 controlled trials against placebo or control. Active-arm doses ranged from about 4 to 100 mg/day, with treatment durations of 4 to 12 weeks; formulations included capsaicin, chili supplement, Kochujang pill, METABO pill, and other capsaicinoid mixtures.

Capsaicinoid supplementation was associated with lower serum total cholesterol and LDL, but not HDL, triglycerides, fasting glucose, or insulin. Reported effects were significant for total cholesterol in dietary capsaicinoid alone analyses (p = 0.004) and capsaicinoids in mixture analyses (p = 0.001), and for LDL (p = 0.035). The authors concluded that dietary capsaicinoids may improve lipid profiles in humans, but the certainty of evidence was low and the findings need confirmation in more randomized trials.

The evidence base was small, with only 10 trials and 199 participants across active arms, and treatment formulations, doses, and durations were heterogeneous. The authors noted low certainty of evidence and substantial heterogeneity. Adverse events and several participant characteristics were incompletely reported, limiting interpretation and generalizability.