Gut Bacterium Linked to Stronger Muscles Across Humans and Mice

A human/mouse study ties Roseburia inulinivorans, a gut bacterium, to greater muscle strength. In humans, higher bacterial abundance correlated with stronger grip and other strength metrics in both young and older adults. In mice, the bacterium boosted forelimb grip by about 30% and promoted fast-twitch muscle growth by altering amino acid metabolism and related pathways, supporting a gut-muscle axis and suggesting probiotic approaches to help preserve muscle strength with aging.