Often, we associate bacteria with negative effects on our immune system—but that’s not the case when it comes to probiotics. These powerful microorganisms help your gut maintain balance—and are especially important for athletes. Read on for the 411 on probiotics for athletes: everything you need to know about keeping a healthy gut throughout your training.

Why Do Athletes’ Guts Need Help?

The beneficial bacteria known as probiotics support your microbiome, the community of bacteria that exists within your gut, which, in the long run, supports immune function.

Thing is, athletes tend to struggle with poor gut function—and increased inflammation throughout the body. Why? Experts hypothesize the strain extensive training puts on athletes’ bodies may be to blame. “There may be a link between vigorous exercise that athletes do, and some kind of microbiome alteration,” explains Monica Auslander Moreno, MS, RD, LD/N, a nutrition consultant for RSP Nutrition.

Probiotics for Athletes: Endurance Exercise And Gut Health

Running (specifically long distances) can be especially rough on the gut, adds Dana Angelo White, MS, RD, ATC, cookbook author, and certified athletic trainer. Distance running not only dehydrates you faster but also diverts blood flow from the organs to the muscles, which can lead to digestive issues, she says.

The effect? In one recent study, researchers found that though marathon runners didn’t lack diverse gut bacteria, they had fewer gut bacteria in their microbiome after a race than they did before. (They suspect that digestive changes aside, metabolic changes in the blood and muscles during hard-core distance running also impact the gut bacteria.)

Experts believe the inflammation triggered by endurance exercise may also be problematic. While this exercise-induced inflammation (in the right doses) is necessary and beneficial, it often kicks into overdrive in endurance athletes. And considering at least 70 percent of the immune system resides within the gut, this spells trouble for our microbiomes.

“Endurance athletes may experience more of a depressed immune function than those who undergo normal physical activity due to a constant ‘turning on’ of the inflammation response,” explains Maggie Luther, ND, Care/of's Medical Director and Formulator.

However, the workouts themselves aren’t the only factors influencing athletes’ microbiomes. Other factors include:

poor diet
high stress levels
lack of sleep
under-hydration

How to Add Them To Your Diet

Though more research will illuminate the exact relationship, athletes’ guts and immune systems can certainly benefit from increasing their probiotic intake

In fact, a few small studies suggest that probiotics can assist the body in recovering from fatigue due to intense exercise.

To up your intake, most dietitians recommend opting for fermented foods (which provide probiotics) over probiotic supplements, which are often recommended for people with Inflammatory Bowel Disorders. Often, these fermented foods provide additional beneficial nutrients, such as the protein and calcium in Greek yogurt.

Though experts don’t know exactly how many additional probiotics athletes need (the ‘perfect’ microbiome is still a bit of a mystery!), one or two daily servings of fermented foods, can only help your nutrition and gut microbiome, says Moreno.

For breakfast, consider a smoothie made with yogurt or kefir, or drinking some kombucha. For lunch, try using kefir as the base of a creamy salad dressing by adding fresh herbs, garlic, honey, and lemon. “For dinner, cube up some tempeh [made from fermented soy] and toss it into a stir fry,” suggests White. “Or, crumble and sauté it with seasonings for a plant-based taco filling.”

If you do choose to use probiotic supplements (like when traveling or have limited access to fermented foods), make sure the supplements contain two types of bacteria: lactobacillus and bifidobacterium. According to Luther, both of these are needed in different regions of the digestive system.

However, since there are so many different supplements out there, talk to your healthcare provider before starting to take probiotic supplements.

Probiotics for Athletes: The Bottom Line

Athletes, if you want to keep your health in tip-top shape, your top priority is to nourish your microbiome and maintain healthy habits every day you train. “An athlete can support his or her microbiome by hydrating properly, getting adequate sleep, controlling stress, and consuming a variety of fiber-filled plant foods (which contain prebiotics, the food source for probiotics), and some fermented foods as well,” says Moreno.