Abstract / Summary
Background Weight reduction before competition has long been a major challenge for combat-sports athletes. Unscientific weight-loss practices not only increase the risk of hormonal imbalance, electrolyte disturbance, and impaired immune function but also compromise athletic capacities such as aerobic and anaerobic performance and explosive power. This study investigated the potential benefits of tangeretin, a natural citrus extract, on athletic performance. These benefits include the regulation of hormone secretion, the optimization of carbohydrate and lipid metabolism, and the promotion of muscle synthesis and lipid utilization, which may help athletes reach their target weight.Objective To examine the effects of tangeretin supplementation on body-composition and sports-performance indicators in female combat-sports athletes, and to evaluate its efficacy for simulated precompetition weight loss.Methods Thirty female combat-sports athletes (4 wrestlers, 3 boxers, 9 sanda athletes, 3 judokas, and 11 taekwondo athletes) were recruited. A paired, randomized, double-blind design was used. All 30 participants were first paired according to sport and competitive level, then randomly allocated to either a tangeretin group or a placebo group (15 per group). The 30-day intervention comprised a double-blind nutritional supplement, a dietary questionnaire, blood sampling and analysis, body-composition assessment, isokinetic muscle-strength testing, and aerobic-capacity testing, to evaluate the effects of tangeretin (400 mg/day) on performance and health-related outcomes. These outcomes included body-composition indicators (e.g. body-fat percentage, fat mass, lean-body mass), fat-distribution indicators (e.g. limb and regional fat mass, gynoid fat mass), glucose and lipid-metabolism indicators (e.g. LDL-C, total cholesterol, free fatty acids), hormone indicators (e.g. cortisol, testosterone), muscle-strength indicators (e.g. peak torque of hip, knee, and ankle flexors and extensors), and maximal-oxygen-uptake-derived indicators (e.g. VO2max heart rate, time to exhaustion). Statistical significance was assessed using two-way repeated-measures analysis of variance (ANOVA).Results (1) Body weight: 80.0% of athletes in the tangeretin group lost weight to varying degrees, and 33.3% (5 athletes) reached their competition weight class. (2) Body fat: body-fat percentage in the tangeretin group decreased from 23.92 ± 0.87% to 22.92 ± 0.89%; trunk, upper-limb, lower-limb, and android-region fat mass decreased by 6.77%, 8.77%, 4.43%, and 8.09%, respectively. (3) Glucose and lipid metabolism: HDL-C increased by 8.86% (P = 0.002), whereas triglycerides decreased by 25.00% (P = 0.048). (4) Sports performance: peak torque during hip, knee, and ankle flexion and extension increased significantly in the tangeretin group. VO2max also improved from 42.80 ± 1.13 to 43.46 ± 1.32 ml/kg/min.Conclusion Tangeretin supplementation effectively reduced body weight and fat mass (both overall and regionally) in female combat-sports athletes. Among the participants, 80.0% lost weight to varying degrees, and 33.3% reached their competition weight class, indicating a strong effect on precompetition weight loss. Moreover, tangeretin improved aerobic capacity and lower-limb joint muscle strength, thereby enhancing competitive performance.