Muscles change with age and not for the better! Without strength training, the amount of muscle on your frame will peak by the age of 35. Once guys and gals reach their mid-30s, they begin to lose muscle tissue and gain body fat. Plus, the rate of muscle loss increases during late middle age. A bad combination! However, active people, especially those who strength train, lose muscle mass at a slower rate. In fact, studies show that some older people who lift weights with intensity have a muscle composition consistent with someone twenty years younger. Such is the power of lifestyle habits!
Physical activity and working your muscles against resistance play a key role in preserving muscle mass, but other factors play a role too. What you eat is a factor that impacts body composition. If you don’t consume enough total calories and get enough protein, your body enters a catabolic state and you break down muscle tissue. But there may be more to the story. Animal studies suggest that the composition of an individual’s gut microbiome may play a role in age-related muscle loss too. Can a healthy gut boost the health of your muscles or slow muscle aging?
The Bacteria That Make Up Your Gut Microbiome
Your gut microbiome is a busy hub of organized activity. Trillions of bacteria make their home in your large intestines where they impact nutrient absorption and digestive and immune health. There’s still much to learn about the gut microbiome, but studies suggest that a more diverse population in the gut offers greater benefits for health and weight control. But let’s look beyond weight and look at the role gut bacteria play in muscle composition.
For the study, the researchers first tested the strength of mice, some of whom had a normal gut microbiome and others that had a gut devoid of bacteria. Yes, scientists have ways of testing how strong a mouse is! They found that the mice that had no microbiome had weaker muscles and their muscles were less metabolically active relative to the mice with a normal gut microbiome.
What happens if you give mice free of gut bacteria a gut microbiome? When they placed gut bacteria from the mice with a healthy population of gut microbes into the mice that had none, the mouse recipients exhibited greater muscle strength and function. The researchers also found that mice without a microbiome lacked certain proteins important for movement. When they gave the mice devoid of a microbiome the gut bacteria from the normal mice, they restored these proteins.
As mentioned, the mice without gut bacteria also had muscles that were less metabolically active and produced less energy. Plus, they had mitochondria that didn’t function well. As you know, mitochondria are the energy-producing organelles that make ATP, the high-energy molecules that allow muscles to contract. When they shifted some bacteria from the healthy mice to the microbiome-free mice, their mitochondria “perked up” and produced more ATP.
At least in mice, gut bacteria and gut microbiome composition play a role in how muscles function. Could the same be true in humans? It’s harder to carry out such a study on humans as the researchers would have to start with people with no gut bacteria. Yet, the results suggest that gut bacteria and the microbiome may be a factor in how strong, healthy, and functional muscles are, assuming that humans are like mice in this respect. It’s also possible that changing the composition of a person’s gut bacteria could improve how their muscles function and even slow muscle loss due to aging.
Can Taking Probiotics Improve Muscle Function?
If the gut microbiome plays a role in muscle strength and function, the next question is whether taking probiotics can enhance muscle health or performance. Probiotics are gut bacteria that offer benefits to the host. Some people get probiotics by eating fermented foods while other people take a supplement that contains these organisms. Consuming prebiotics also supports the health of beneficial gut bacteria by supplying them with energy. Although humans can’t break down fiber and use it as an energy source, bacteria can. Prebiotics are like food for bacteria.
Could taking a probiotic be beneficial to athletes and people who lift weights? Possibly. Some studies suggest that probiotics boost the uptake of amino acids from protein by the small intestines. A study published in the Journal of the International Society of Sports Nutrition found that Bacillus coagulans spores, probiotic bacteria, improved muscle recovery and reduced muscle soreness in athletes. If cells can more efficiently take up protein, that’s a good thing, but it doesn’t necessarily mean it leads to greater muscle growth. Currently, there’s no strong evidence that taking probiotics will boost muscle growth or prevent muscle loss. However, it may help with muscle recovery.
Another way that probiotics may be beneficial for muscle recovery is by boosting immune function. Studies show that probiotic bacteria may reduce the risk of some viral and bacterial infections by competing for resources with pathogenic bacteria and by their impact on the activity of immune cells. After an intense workout or one of long duration, such as long-distance running, you’re more susceptible for a few days to pathogens like viruses. If you’re not sleeping enough or getting inadequate nutrition, you’re even more susceptible to pesky cold and flu viruses.
You Don’t Need a Probiotic Supplement
This study might tempt you to invest in a bottle of probiotics. Swallowing a probiotic supplement sounds attractive, but you can’t be sure that the probiotic organisms in the capsule are viable. Instead, why not add more fermented foods to your diet? Fresh sauerkraut, other fermented vegetables, miso, and kefir are good options. Plus, you’ll also enjoy the added nutrients these foods offer, something you won’t get from swallowing a probiotic capsule. In addition, fermented vegetables contain prebiotics that helps probiotic bacteria survive and thrive. It’s no guarantee that it will boost muscle growth or muscle function, but it can improve your digestive health and support the health of your immune system. Plus, not all probiotic supplements contain enough viable organisms to have benefits. So, why not add more probiotic-rich foods to your diet instead?
· Nutrients. 2019 Jul; 11(7): 1633. Published online 2019 Jul 17. doi: 10.3390/nu11071633.
· Medical News Today. “Could gut microbes be the key to overcoming muscle loss in older age?”
· J Int Soc Sports Nutr. 2015; 12(Suppl 1): P36. Published online 2015 Sep 21. doi: 10.1186/1550-2783-12-S1-P36.
· Mayo Clinic. “Probiotics May Be Effective in Preventing the Common Cold”