Could one gut bacterium be linked to muscle strength in aging?

News summary

ScienceDaily reported that the gut bacterium Roseburia inulinivorans is linked to greater muscle strength. The Gut paper examined this association in younger and older human cohorts and then tested the candidate bacterium in mice. In humans, its abundance was positively associated with several strength measures, while supplemented mice showed improved forelimb grip and changes in muscle-fiber characteristics.

R. inulinivorans, unlike several other Roseburia species, was associated with handgrip, leg-press, and bench-press strength in humans. Supplementation in mice increased forelimb grip strength and was accompanied by larger muscle fibers and changes in muscle metabolic pathways.

The result is intriguing, but it does not mean an anti-sarcopenia probiotic is ready for use. Human intervention trials are needed to determine whether deliberately increasing this bacterium can actually improve muscle strength.

The human component is largely associative and cannot establish causality. Causal testing was performed in mice, so translation to humans requires caution. The human bacterial strains also did not permanently colonize the mouse gut.