Ageing naturally weakens our muscles, but a new study published in the journal Gut have found a gut bacterium that may help turn the tide. The researchers Leiden University Medical Center and the Universities of Granada and Almería, found that Roseburia inulinivorans is linked to stronger muscles in both people and mice. The discovery hints at the potential for new probiotics to support muscle strength and healthy ageing.
While exercise and good nutrition remain important for maintaining muscle strength, scientists are now turning their attention to a lesser‑known player: the gut. “The bacteria living in our intestines help us process nutrients, regulate inflammation and manage energy,” Patrick Rensen, professor at the division of Endocrinology, notes. “All of these processes are essential for keeping our muscles healthy as we age.”
A gut bacterium linked to stronger muscles
In their new work, the researchers identified one particular gut bacterium, Roseburia inulinivorans, that appears to be linked to stronger muscles across the lifespan. “When we compared young adults aged 18 to 25 with older adults aged 65 and above, we noticed clear differences,” postdoc Borja Martínez-Téllez says. “Older adults who carried this bacterium had 29 percent stronger handgrip strength than those who didn’t.” In young adults, higher levels of Roseburia inulinivorans were associated with stronger muscles and better overall fitness. “It was remarkable to see the same pattern in both age groups,” Martínez-Téllez adds.
Testing the bacterium in mice
To find out whether this link was more than coincidence, the researchers carried out a series of experiments in mice. “We wanted to understand whether this bacterium actually causes improvements in muscle strength,” Rensen explains. After clearing the mice’s gut bacteria using antibiotics, they introduced human strains of Roseburia inulinivorans for eight weeks.
“The results were striking,” Rensen says. “The mice became 30 percent stronger, developed larger muscle fibres and produced more fast‑twitch fibres.”
The team also found that the bacterium changed how the muscles used certain building blocks and activated energy‑related pathways inside the muscle. “These metabolic changes may help explain why the muscles grew stronger,” according to Martínez-Téllez.
From discovery to potential probiotic treatment
Another key observation is that levels of Roseburia inulinivorans naturally decline with age. “This could partly explain why muscle strength drops as we get older,” Martínez-Téllez says. “If this bacterium supports muscle metabolism, then restoring it might one day help preserve muscle function later in life.”
Together, the findings suggest that Roseburia inulinivorans could become a future probiotic, developed into a safe, supplement‑like product aimed at preventing age‑related muscle‑wasting conditions. “A nutraceutical approach – using food‑based or naturally derived products – could offer a gentle and non‑invasive way to support healthy ageing,” Martínez-Téllez explains.
The researchers however caution that considerable work needs to be done before these findings can be turned into a treatment for humans.
Source: Leiden University Medical Center
