We know our gut is teeming with trillions of bacteria and these friendly gut bacteria make up our microbiome. Just like a fingerprint, your gut microbiome is your signature and is entirely unique to you. In the last few decades, research into how the microbiome impacts health has accelerated and continues to be a strong area of focus. Although this research is still in its preliminary stages, it appears that the bacteria that call your gut home play a key role in digestive health and in maintaining a balanced immune system. The latter isn’t surprising since 70% of your immune system lies in your gut.
Recently, studies have also looked at whether the gut microbiome impacts exercise performance and whether it plays a role in exercise recovery. Although we don’t know for sure, some studies suggest that having the right population of gut bugs could help you better recover from a workout. That’s a good reason to nibble on yogurt, isn’t it?
Probiotics, Exercise, and Muscle Repair
After a workout is when your muscles must repair the damage that exercise subjected them too. When you do a strength workout, the stress of training against heavy resistance creates microscopic muscles tears in muscle fibers that need to be repaired. It’s through the repair process after a workout that muscles grow in strength and size. After a tough session of lifting more weight than your muscles are accustomed to, you may experience delayed-onset muscle soreness, muscle pain, and stiffness 24-48 hours after the workout ends. That’s a familiar feeling, isn’t it? Due to delayed-onset muscle soreness, or DOMS, the muscles you worked might feel stiff and sore for a few days up to a week. After such a muscle-damaging session that triggers DOMS, researchers can measure the impact on the muscle by quantifying levels of certain blood markers that indicate muscle damage.
What do these markers tell us? In one study carried out by researchers at the University of Tampa Human Performance Research Lab and Increnovo, researchers measured baseline blood tests on 34 healthy, trained males, including blood markers of inflammation. They then asked the men to supplement with 20 milligrams of casein protein. After 14 days of supplementation, the guys performed muscle-damaging exercise. After a wash-out period, they asked the participants to again supplement with a combination of 20 milligrams of casein (as before), plus species of B. coagulans, a type of probiotic bacteria. Again, they carried out muscle-damaging exercise. After checking levels of inflammatory markers, the markers of muscle damage were lower after the casein/probiotic combination. The guys also reported feeling less stiff and sore after the probiotic/casein combo.
What does this mean? It suggests that adding a certain strain of probiotics to a protein supplement may reduce markers of muscle damage and DOMs, thereby aiding in exercise recovery. One word of caution though. The increase in inflammatory markers that happens after an intense workout indicates that your muscles are working hard to repair the damage sustained through training. If probiotics interfere with this response, will it also reduce muscle gains? That’s a question that is, as of yet, unanswered. Some, but not all studies, show that anti-inflammatories, like ibuprofen, and even supplemental antioxidants, can interfere with muscle gains if you take them too close to a workout.
Probiotics and Endurance Exercise
How about non-strength training exercise? Probiotics may offer benefits if you do long periods of endurance exercise, like running. Studies show that doing intense exercise for long periods of time, such as running a marathon, can disrupt the thin lining of the small intestines, and cause leakage of proteins into the bloodstream. This condition is called “leaky gut.” What’s concerning is some experts believe leaky gut can trigger inflammation, oxidative stress, and even autoimmune reactions as proteins from the leaky intestinal tract enter the bloodstream. Probiotics may help to prevent this by closing the “tight junctions,” the spaces between cells in the small intestines so that these proteins can’t escape and cause the immune system to overreact.
Does this play out in real life? In one study, supplementing with 14 weeks of a probiotic consisting of multiple species reduced a marker associated with increased intestinal permeability, suggesting that the small intestinal barrier was more intact, even after exercise. So, long-distance runners and other people who do exhaustive exercise could benefit from probiotics as well.
In addition, exhaustive exercise temporarily suppresses the immune system, though moderate amounts of exercise seem to have an immune-enhancing effect, suggesting the effect of exercise on immunity follows a J-shaped curve. You can definitely overdo it! For example, marathon runners are 2 to 6 times more likely to develop an upper respiratory infection within 2 weeks after a marathon run. Why does this happen? Strenuous exercise releases stress hormones, like cortisol, that temporarily suppress immune function. Scientists are looking at whether probiotics, by altering immune function, can protect against immune suppression related to exhaustive exercise.
Do You Need a Probiotic Supplement?
You might be tempted to take a probiotic supplement if you exercise. However, it’s not clear which strains offer the most health and fitness benefits. A better approach might be to eat a diversity of fermented foods, like kimchi, sauerkraut, other fermented vegetables, miso, and tempeh since these foods contain a diversity of organisms. You don’t always know what you’re getting when you buy a probiotic supplement. For example, some of the bacteria in a supplement may no longer be viable. If you do decide to take a supplement, look for one that has at least a billion active bacterial cells and buy it from a reputable company.
The Bottom Line
It’s too early to say that probiotic bacteria positively aid in exercise recovery, although some studies suggest they help reign in the inflammatory response after a workout. Plus, they may help prevent the drop in immunity that happens after an intense workout. One thing that is clear – healthy gut bacteria makes your intestinal tract a healthier place. But, consider getting probiotics from food sources. Fermented vegetables are an excellent choice because they also contain fiber for the bacteria to feed on.
References:
Natural Product Insider. “Probiotic May Help Protein Utilization for Improved Recovery and Performance”
PeerJ. 2016; 4: e2276. Published online 2016 Jul 21. doi: 10.7717/peerj.2276.
Journal of the International Society of Sports Nutrition 20129:45
Sciencebased Medicine. “Everything You Always Wanted to Know about Fermented Foods”
Exerc Immunol Rev. 2009;15:107-26.
Microbe Blog. “Exercise, immunity and probiotics”
Related Articles by Cathe:
The Problem with Probiotic Supplements: Are They What They Seem to Be?
Can Probiotics Help with Exercise Recovery?
Fermented Foods vs. Probiotic Supplements: Is One Better Than the Other?
3 Ways Gut Bacteria Affect Body Weight
Top 4 Reasons to Cultivate Healthy Gut Bacteria
