Research from a mouse study carried out by the University of Kentucky suggests that having an unhealthy or disrupted gut microbiome could impair muscle growth.
The gut microbiome is known to impact many different areas in our bodies and have a big influence our overall health. There have been a few studies suggesting it may impact muscle growth in mice and also pigs, among other species, but evidence to support this hypothesis is still fairly limited.
To explore this area further, John McCarthy, Ph.D., an associate professor at the University of Kentucky and lead researcher on the study, and colleagues carried out a study in mice to assess how having a disrupted microbiome due to antibiotic treatment impacted muscle formation after exercise.
Overall, 42 female mice were included in the study. The animals were randomly assigned to receive antibiotics in their drinking water or to be in the control group. The mice were then given access to running wheels for nine weeks.
Although both groups of mice ran for a similar amount of time during the training period, the mice that received antibiotics—and therefore had a depleted gut microbiome—had slower and less pronounced muscle growth in response to exercise compared with the mice in the control group.
As reported in The Journal of Physiology, serum levels of cytokine proteins did not differ between different groups suggesting that inflammation was not to blame for the differences the researchers observed.
Although these findings were only in mice and need to be investigated further, they add to other studies suggesting that the microbiome may play an important role in muscle growth.
Taylor Valentino, graduate student at the University of Kentucky and first author on the paper, said: “If we can identify the substances that gut bacteria are making to help muscle growth after exercise, we might be able to use some of those substances to promote the growth of muscles in people suffering from the loss of muscle as typically seen with aging or cancer.”
This is not the first time that differences in gut bacteria have been observed to act on the body’s response to exercise. For example, a Nature Medicine article published in 2019 showed that having an abundance of the bacteria Veillonella atypica seemed to increase endurance ability due to its lactate metabolizing abilities both in mice and humans.
“From an athletic standpoint, world-class runners were found to have more of a particular type of bacteria that provided an additional source of energy which was thought to help them run faster. Thus, the gut microbiome makes substances that appear to be important for skeletal muscles to fully adapt to exercise as well as help improve athletic performance,” said McCarthy.
“We are currently trying to determine how exercise changes the composition and function of the gut microbiome. This investigation, along with other studies in bacteria, will allow us to identify the substances made by the gut microbiome that help skeletal muscle to grow larger in response to exercise.”