Bile acid profiles reflect metabolic adaptability to rapid weight loss in boxers

PURPOSE: This exploratory pilot study investigated serum bile acids (BAs) as metabolic regulators in boxers, focusing on their dynamic responses to rapid weight loss (RWL) and recovery across different training levels. A developmental control group of young athletes served as a physiological reference. METHODS: Serum samples from 13 male boxers (5 elite, 8 national-level) and 10 young athletes were collected at baseline, post-RWL, and after 24 h recovery. Targeted liquid chromatography–tandem mass spectrometry (LC–MS/MS) quantified 82 BA species. Multivariate (OPLS-DA), univariate, and KEGG pathway analyses assessed phase- and level-dependent differences. RESULTS: Elite boxers showed higher baseline concentrations of conjugated and regulatory BAs (e.g., taurolithocholic acid [TLCA], glycohyocholic acid [GHCA]) and faster post-RWL restoration of BA balance. Non-elite athletes exhibited stronger shifts toward unconjugated secondary BAs (e.g., deoxycholic acid [DCA], lithocholic acid [LCA]) and incomplete recovery. Compared with young athletes, trained boxers displayed enhanced BA conjugation and FXR/TGR5-linked regulation. KEGG analysis indicated RWL-related disturbances in bile secretion and peroxisomal pathways, while elite profiles reflected greater hepatic–intestinal resilience. CONCLUSION: BA composition may serve as a biochemical marker of metabolic adaptability in combat athletes. Elite boxers maintained tighter BA homeostasis through weight cycles, whereas non-elite athletes exhibited transient hepatic stress. Findings are preliminary and should be interpreted cautiously due to small subgroup sizes and unstandardized diet and microbiome control.