The Role of Gut Microbiome on Muscle Mass
I wanted to discuss an exciting area of research regarding the microbiome's role in developing muscle mass. So far, there are mainly pre-clinical trials (animal studies) on the effects of the gut microbiome. Although more research is needed, it is still worth looking at the sum of the evidence to see how else the microbiome can be crucial.
Initially, muscle mass and the health microbiome were negatively correlated in germ-free mice (1). This study examined how the gut microbiome is associated with fat storage. So, the study didn't specifically examine skeletal muscle mass since it looked at all types of lean mass in the mice.
Studies have found a positive correlation between muscle mass and gut health in recent years. The composition of the gut microbiome has been shown to correlate with health outcomes. Similarly, certain bacterial types have been associated with increased muscle mass. Lactobacillus casei and Bifidobacterium longum are two bacterial types related to increased muscle mass (2).
One of the primary metabolites our gut microbiome produces is short-chain fatty acids (SCFAs). Acetate, propionate, and butyrate are all SCFAs. Studies have shown that mice fed these SCFAs increase their muscle mass (3).
How about in humans? One of the primary studies I found looked at healthy menopausal women. The study indicated butyrate increased skeletal muscle mass. This is more evidence showcasing the importance of the metabolites produced by the gut microbes (4).
With more research in this area, we can determine specific mechanisms and healthy gut compositions. We have many tools to assess the microbiome's composition.
