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What Runners Should Know About Prebiotics and Probiotics

And how they work together in synbiotic products.

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“Runners are notorious for getting [gastrointestinal] problems,” says nutritionist Melissa Daniels. And even if you don’t fall into that notorious category, it’s worth paying attention to your gut health. As it turns out, the bacteria in our bowels are pulling a lot of strings all over the body. And for some people, prebiotics and probiotics could be the key to figuring out what ails them. 

An imbalanced gut microbiome can affect the body’s ability to absorb nutrients that are key to strong running. It also plays a role in immune health and even sleep. “Sleep, body composition, immune system, and energy levels can also be impacted by the microbiome which is why proper gut health is crucial,” says Daniels.  

Greg Grosicki, director of Georgia Southern University’s exercise physiology lab is interested in how these systems work together. “We’ve known for a while that there’s a relationship between the gut and the brain and this bidirectional communication access through the Vagus nerve,” he outlined in a recent GU Energy Lab webinar. As an example, he notes that people with sleep apnea tend to also have an unhealthy gut microbiome. In a study his lab published earlier this year they found that microbial diversity in the gut was positively associated with better sleep quality, as was self-reported by the participants. 

Furthermore, research conducted in animal models have found that the fatty acids produced by healthy gut bacteria improved REM sleep. That particular fatty acid, butyrate is produced when your diet is full of fiber. “We get the right bacteria, we give them the right substrate to build butyrate, we increase butyrate, we sleep better, we make our gut healthier, and we fortify our immune system that way,” Grosicki says. 

Emerging research is beginning to show that the gut microbiome is linked to other psychological symptoms like stress and anxiety. The University of Virginia’s TransUniversity Microbiome Initiative website lists depression as an implicated problem on the rise due to microbiome imbalance. But more research is needed in understanding how the microbiome interacts with psychological wellbeing. 

Various types of prebiotics and probiotic strains, found in a diverse diet, can help strike a balance in building a healthy gut.

Fermented foods like kimchi and sauerkraut are a natural source of probiotics. Photo: Getty Images

How Probiotics Work

According to the International Scientific Association for Probiotics and Prebiotics (ISAPP) a probiotic is a living organism that elicits a positive health benefit, and therefore, not every living microorganism is a probiotic. The job of an introduced probiotic is to support the 38 trillion microbes that make up the microbiota. 

When consumed, they enter into the digestive tract and work with the microbes in your gut to perform beneficial physiological functions like extracting nutrients from food, fighting off bad bacteria, and improving the intestinal barrier. 

“Probiotics can be a great supplement for runners to take to help reduce the common GI distress of bloating, nausea, and diarrhea,” says Daniels who is also the director of managed plans at G-Plans. When running, blood flow gets directed away from the digestive tract to the muscles, causing an inflammatory response. Probiotics can address this inflammation. A recent study published in the journal Sports Nutrition found that probiotic supplements reduced GI distress severity and frequency in athletes when used for at least 11 weeks during training and competition.

They can also support your immune system in building back good bacteria if their balance has been disturbed in cases of illness, antibiotic use, or stress. “While more research is needed, probiotics can strengthen our immune system by creating a balance between the good and bad bacteria making pathogens less likely to take hold in the body,” says Daniels.

Probiotic Foods to Try

Fermented foods (like kimchi, sauerkraut, miso, and tempeh) are a natural source of probiotics. But the shelf-stable versions of those typically go through a heating process that kills the microbes. You can look for products that say ‘contains live cultures’ on packaging. The same goes for cultured foods like yogurt and some soft cheeses like chèvre. ISAPP recommends trying a new food or supplement for at least a month before determining if it works for you or not. 

Probiotic Supplements

According to Daniels, supplements on the market will typically contain strains from the Lactobacillus and Bifidobacterium genuses. “Lactobacillus acidophilus is arguably the most popular strain found in probiotics due to its wide range of benefits. This strain helps support a healthy immune system, balance the microbiome, and aid in digestion which can alleviate most common GI symptoms,” she says. Some scientists, like this University of Virginia Lab that has received a special grant from the Bill and Melinda Gates Foundation, are trying to figure out how to develop custom blends of microbes to dial in specific needs for patients.

How Prebiotics Work

Not to be confused with their living counterparts, prebiotics are the food for the beneficial microbes that already exist in your gut. They can help to improve calcium absorption and regulate blood sugar. Most prebiotics are a type of dietary fiber, but not all dietary fiber is a prebiotic. It is recommended that adults consume at three to five grams of prebiotics daily. 

Prebiotic Foods to Try

Onions, garlic, bananas, whole grains, beans, chicory root, and artichokes are naturally rich in prebiotics. Some foods can also be fortified with these prebiotic carbohydrates. Look for these words on nutrition labels:  galacto-oligosaccharides (GOS), fructo-oligosaccharides (FOS), oligofructose (OF), chicory fiber, or inulin. 

Synbiotics: Combining Prebiotics and Probiotics

The combination of these microbiome benefitting products is a recently defined term: synbiotics. Synbiotic products combine both live microorganisms (the probiotic) and the selected substrates (the prebiotic) to produce a health benefit. But these products are still sort of in the beginning stages of being researched and developed. The term was first introduced in 1995, but a consensus panel recently got together to solidify a definition to keep the scientific research and development on track.

“We expect that the scientific data on synbiotic health benefits will increase over time, alongside an increase in general awareness about synbiotics,” ISAPP’s executive science officer, Mary Ellen Sanders said in a press release. The synbiotic market could be the next big nutrition industry boom.

With that, researchers urge consumers to speak with their doctors before exploring new supplements and that includes prebiotics and probiotics.