Gut Bacteria Boosts Muscle Strength by 30% in New Study

Getting stronger might be as simple as taking the right probiotic, if exciting new research pans out.

Scientists at the University of Granada discovered that a specific gut bacterium called Roseburia inulinivorans makes muscles stronger and bigger. When they gave this microbe to mice, the animals showed 30% greater grip strength and developed thicker, more powerful muscle fibers.

The discovery started when researchers tested 123 people of different ages. They collected stool samples to analyze gut bacteria and measured everyone's grip strength with a handgrip test.

A clear pattern emerged. People with more Roseburia bacteria in their guts had noticeably stronger grips. Older adults with the bacterium showed 29% greater strength than those without it, while younger adults showed better cardiorespiratory fitness too.

The team noticed something troubling. Older adults generally had much lower levels of this helpful bacterium, which might explain why we lose strength and muscle as we age.

To prove the bacterium was directly responsible, scientists ran experiments with mice. They introduced Roseburia inulinivorans into some mice while leaving others as controls.

The results were impressive. Mice that received the microbe got 30% stronger in just weeks. Even more exciting, their muscle composition changed: they developed a larger share of fast-twitch muscle fibers, the explosive type that athletes work hard to build.

The Bright Side

This research offers hope for millions facing age-related muscle loss. Professor Jonatan Ruiz, who co-authored the study published in the journal Gut, says the findings confirm a real connection between gut bacteria and muscle strength.

The possibility of creating a probiotic supplement to maintain strength during aging or help people with muscle-wasting disorders is now on the table. Since humans already have this bacterium naturally, scientists aren't introducing something foreign.

Some important questions remain unanswered. The human strains didn't permanently settle in the mice's intestines, and researchers need to understand the long-term effects. The study's human sample size was relatively small at 123 participants.

What works brilliantly in mice doesn't always translate to humans. More research with larger groups over longer periods will be needed before anyone can buy a strength-boosting probiotic at their local pharmacy.

Still, co-author Borja Martínez Téllez sees real potential. If future studies confirm these results, this bacterium could become a tool to help people preserve their strength and independence as they grow older.

The discovery connects to growing evidence that our gut bacteria influence our bodies in profound ways beyond digestion, from metabolism to heart health to muscle function.