A recent study has identified a specific gut bacterium, Roseburia inulinivorans, that may play a role in maintaining muscle strength as people age. Researchers analysed the gut microbiomes of 90 young adults aged 18-25 and 33 older adults aged 65-75, finding that higher levels of this bacterium were associated with stronger performance in muscle strength tests, including handgrip strength.
To investigate whether the bacterium directly influences muscle strength, the team conducted experiments in mice. After reducing the animals' existing gut microbes, they introduced Roseburia inulinivorans. Mice that received the bacterium developed noticeably stronger grip strength and larger muscle fibres, particularly type II fibres associated with powerful movements.
Further analysis suggested that the bacterium may affect how muscles use energy. In mice given R. inulinivorans, energy-related pathways in muscle cells became more active, while levels of certain amino acids decreased in the gut and bloodstream. The human data also showed that older adults tended to have lower levels of this bacterium than younger participants, aligning with age-related declines in muscle strength.
The findings raise the possibility of developing probiotics containing Roseburia inulinivorans to support muscle function in older age. However, the researchers caution that correlation does not imply causation in humans, and larger studies are needed to confirm the relationship. Diet, particularly prebiotic fibres that feed beneficial gut bacteria, may also help promote the growth of this microbe.
