A nutritive dose of pure (-)-epicatechin does not beneficially affect increased cardiometabolic risk factors in overweight-to-obese adults-a randomized, placebo-controlled, double-blind crossover study.

Randomized, placebo-controlled, double-blind crossover study in overweight-to-obese nonsmoking adults with signs of metabolic syndrome. Participants were aged 20 to 65 years and were studied in Germany; 48 were randomized and 47 were included in the per-protocol analysis.

Oral capsules containing 25 mg/day of pure (-)-epicatechin were taken daily for 14 consecutive days. The trial used a matched placebo capsule in a randomized, double-blind crossover design.

Daily 25 mg (-)-epicatechin for 2 weeks did not improve cardiometabolic risk factors in overweight-to-obese adults with metabolic-syndrome features. Blood pressure was not affected by treatment or by treatment by time interaction; SBP and DBP showed only time effects (P = 0.011 and P = 0.029), with no significant post hoc differences. Glucose, insulin, HOMA-IR, triglycerides, oxidized LDL, vitamin C, vitamin E, beta-carotene, and arginine were unchanged, and total cholesterol, LDL cholesterol, and HDL cholesterol changed only by time (P = 0.002, P = 0.011, P = 0.005) without significant pairwise differences. Body weight, fat mass, waist circumference, and waist-to-hip ratio remained stable, and ITT results were consistent with the per-protocol analysis.

The intervention was short term, with only 2 weeks of supplementation, which limits assessment of longer-term cardiometabolic effects. The sample was relatively small and restricted to overweight-to-obese nonsmokers with metabolic-syndrome features, reducing generalizability. Dietary restrictions and the crossover design may also limit real-world applicability, and adverse events were not reported.