The gut microbiome affects muscle strength, found a study published in the journal Experimental Gerontology. Researchers from Tufts University said that the gut microbiome — the community of microorganisms living in the digestive tract — helps increase or decrease muscle strength depending on the amount of certain bacteria.
The findings of the study benefit not only athletes but also older adults, who commonly lose lean mass and experience decreased muscle strength as a result of age.
“Identifying differences in bacteria present in the high-functioning and low-functioning groups in this study moves us toward a fuller understanding of both the gut microbiome and healthy aging,” said co-author Roger Fielding.
Gut bacteria influence muscle strength
The gut microbiome plays a major role in various body systems. It stimulates the immune system, breaks down food and synthesizes certain vitamins and amino acids. Previous research also found that it is involved in the development of neurological conditions such as Parkinson’s disease.
For their study, the team examined the connection between the gut microbiome and muscle strength among older adults. They compared the gut bacterial composition of 18 physically active individuals with athletic builds to those of 11 sedentary individuals with less athletic builds.
Results show that the bacterial profiles of the two groups were significantly different. For instance, the physically active group had greater levels of Prevotellaceae, Barnesiella, Prevotella and Barnesiella intestinihominis.
To investigate the role of the gut microbiome in muscle health, the team conducted another test by injecting mice with bacteria taken from the two groups. They found that mice injected with bacteria from the physically active group had improved grip strength.
“We now start to understand the role of gut bacteria in the maintenance of muscle strength in older adults,” said co-author Michael Lustgarten. He said that increasing the levels of certain bacteria in the gut will lead to an increase in muscle strength.
While more studies are needed, the researchers said that their findings will greatly benefit the elderly. Age-related muscle loss, or sarcopenia, typically afflicts older adults. By age 30, a person starts losing up to three to five percent of muscles per decade, resulting in gradual weakness and less mobility. In turn, these factors increase a person’s risk of fractures. (Related: Increased protein intake and regular exercise significantly lowers risk of sarcopenia.)
More research on muscle health and gut bacteria
Other studies have also found a link between the gut microbiome and muscle health.
One study, published in journal Science Translational Medicine, found that mice with gut microbes had stronger skeletal muscles compared to germ-free mice.
The researchers examined the muscle mass of mice with and without a trace of microbes in their gut and discovered that germ-free mice had higher expression levels of genes linked to muscle atrophy and reduced muscle mass.
According to the researchers, the germ-free mice displayed problems with the function and generation of new mitochondria in skeletal muscles. The mitochondria is responsible for breaking down nutrients to produce energy for cellular activity.
Furthermore, the germ-free mice had lower levels of proteins related to the assembly and function of a neuromuscular junction. A neuromuscular junction is a chemical structure that enables a motor cell to communicate with a skeletal muscle fiber. These junctions play a role in muscle contraction.
When the germ-free mice were inoculated with gut microbes, the expression of these proteins improved and muscle growth and function were partially restored. The mice also displayed reduced signs of muscular atrophy.
According to Wang Yue of Singapore’s Agency for Science, Technology and Research, research like the present study can lead to novel ways of maintaining and improving muscle health by targeting gut bacteria.
Yue, who was not part of the study, added, “Such strategies are expected to have broad applications in tackling muscle-related health issues. One area with enormous potential is to delay or reverse age-related sarcopenia.”
Learn more about the importance of maintaining a healthy gut microbiota at Digestion.news.