Curcumin supplementation during high-altitude exposure modulates body composition and its relationship with gut microbiota: a randomized controlled trial

BACKGROUND: Body composition is crucial for athletic performance and linked to the gut microbiota. Curcumin shows potential to promote muscle regeneration and modulate fat metabolism, but evidence from high-altitude populations remains scarce. This study aimed to evaluate the effects of curcumin on body composition at high altitudes, and explore potential role of gut microbiota. METHODS: A total of 102 male Han participants was randomized to curcumin (812 mg/d) or placebo groups for 1-week pre-acclimatization and 6-week high-altitude acclimatization. Body composition was assessed via bioelectrical impedance analysis and gut microbiota was analyzed through metagenomic sequencing. RESULTS: After high-altitude acclimatization, curcumin significantly reduced the percent body fat (PBF, P = 0.030). Soft lean mass (SLM), skeletal muscle mass (SMM) and fat free mass (FFM) were increased in both groups, but the curcumin group exhibited greater increases although without significant difference. Curcumin supplementation significantly attenuated the upper-limbs FFM and arm muscle circumference reduction (P < 0.05). The relative abundance of Eubacterium sp. CAG:180 was significantly negative with SLM and SMM (P < 0.05). Curcumin significantly increased the abundance of Bifidobacterium pseudocatenulatum, Eubacterium sp. CAG:274 and Eubacterium eligens (P < 0.01). Higher abundance of Eubacterium sp. CAG:274, Roseburia inulinivorans, and Bifidobacterium pseudocatenulatum were observed in high-skeletal muscle index participants. Lachnospira pectinoschiza, Clostridium leptum, and Eubacterium sp. CAG:274 were more abundant in low-PBF participants. CONCLUSIONS: Curcumin supplementation might increase muscle mass gain and reduce PBF during high-altitude acclimatization that may correlate with changes in gut microbiota composition, and their causal association remains to be further verified. TRIAL REGISTRATION: Chinese Clinical Trail Registry, ChiCTR220005965. Registered on May 5, 2022.