Impact of carotenoids on body composition and adipokine hormones: a systematic review and meta-analysis of randomized controlled trials

Carotenoids, a class of antioxidant phytochemicals, have been proposed to influence adiposity and metabolic regulation through modulation of oxidative stress, inflammation, and adipokine secretion. However, clinical evidence remains inconsistent. This systematic review and meta-analysis aimed to quantitatively evaluate the effects of carotenoid supplementation on anthropometric and adipokine parameters, including body weight, body mass index (BMI), waist circumference (WC), hip circumference (HC), body fat percentage, fat-free mass (FFM), leptin, and adiponectin. Following PRISMA 2020 guidelines, randomized controlled trials (RCTs) published up to October 2025 were identified through PubMed, Scopus, Embase, and Web of Science. Weighted mean differences (WMDs) with 95% confidence intervals (CIs) were calculated using random-effects models. Heterogeneity and publication bias were assessed via I² statistics and Egger’s test, respectively. Twenty-seven RCTs were included. Carotenoid supplementation significantly reduced body weight (WMD: –1.00 kg; 95% CI: –1.87 to –0.13) and WC (–1.78 cm; 95% CI: –3.02 to –0.54), while increasing FFM (+2.32 kg; 95% CI: +0.49 to +4.14). Furthermore, leptin levels decreased significantly (–1.42 ng/mL; 95% CI: –2.35 to –0.49), whereas BMI, adiponectin, HC, and total body fat percentage showed no significant changes. Subgroup analyses revealed stronger effects in interventions lasting >8 weeks and in participants aged <50 years. No substantial publication bias was detected. Carotenoid supplementation exerts modest but favorable effects on body composition and leptin regulation, supporting its potential as an adjunct in metabolic health improvement. Longer, high-quality RCTs are warranted to confirm these findings and clarify dose–response relationships.