A recent Japanese study revealed surprising enhanced sports endurance of human volunteers after long-term consumption of α-cyclodextrin. Oral intake of this oligosaccharide has already been associated with various health benefits, such as induction of weightloss, restoration of gastrointestinal functions after e.g. infection, as well as reduction of postprandial glycemic responses.
Although gut microbiota has been linked to exercise, whether alterations in the abundance of specific bacteria improve exercise performance remains ambiguous. In a cross-sectional study involving 25 male long-distance runners, Morita et al. found a correlation between Bacteroides uniformis abundance in feces and the 3000-m race time. In addition, the authors administered flaxseed lignan or α-cyclodextrin as a test tablet to healthy, active males who regularly exercised in a randomized, double-blind, placebo-controlled study to increase B. uniformis in the gut (UMIN000033748). The results indicated that α-cyclodextrin supplementation improved human endurance exercise performance. Moreover, B. uniformis administration in mice increased swimming time to exhaustion, cecal short-chain fatty acid concentrations, and the gene expression of enzymes associated with gluconeogenesis in the liver while decreasing hepatic glycogen content. These findings indicate that B. uniformis enhances endurance exercise performance, which may be mediated by facilitating hepatic endogenous glucose production.
For 9 weeks, the three groups (12 Japanese males in each) were administered a placebo (placebo group), flaxseed lignanes (200 mg/day, FL group), or αCD (200 mg/day, αCD group) as a supplement. No significant differences were observed in either of the placebo or FL groups at any time points; however, after 4 and 8 weeks of supplementation, the completion times of the αCD group were significantly shorter than those at baseline. α-Cyclodextrin affected B. uniformis abundance, endurance exercise performance (faster running and swimming), and postexercise fatigue, as demonstrated in a randomized, double-blind, placebo-controlled, parallel-group study.
Hiroto Morita , Chie Kano, Chiharu Ishii, Noriko Kagata, Takamasa Ishikawa, Akiyoshi Hirayama, Yoshihide Uchiyama, Susumu Hara, Teppei Nakamura, and Shinji Fukuda (2023) Bacteroides uniformis and its preferred substrate, α-cyclodextrin, enhance endurance exercise performance in mice and human males. Science Advances 9, DOI: 10.1126/sciadv.add2120