How Probiotics Enhance Training

Are probiotics worth the hype? Here’s how they can help boost your training by improving your gut and immunity, and what to look for when shopping for them.


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Over the last few years probiotics have become an increasingly hot topic, and it’s likely that you’ve heard that they can help with training along with offering a cluster of other health benefits. 

Manufacturers and marketers have clearly caught onto the trend, resulting in the supermarket shelves you might have noticed packed with products touting their probiotic properties: Kombucha, kimchi, kiefer, ‘live culture” yogurt, probiotic supplements, etc. 

But are they worth the hype?

Bacterial and Gut Health

Photo: CDC / Unsplash

Here’s the lowdown: Billions of bacteria live inside our gastrointestinal tract. More than 500 of these microbial species are “friendly,” assisting in the function of digestion and supporting the immune system. But many factors can disrupt the balance of healthy bacteria within our gut: medications, stress, fatigue, inflammation, nutritional status and even age. This can result in a reduction of beneficial bacteria, giving potentially harmful bacteria the opportunity to flourish, making us vulnerable to various diseases. Signs of poor gut balance include unpleasant things like stomach cramps, bloating, gas and irregular bowel movements.

This is where probiotics come in. Ingesting certain foods or supplements containing healthy strands of microbiota can help maintain good gut health. Just as important are prebiotics, the non-digestible food particles (think skins of fruits and vegetables, seeds and nuts) that sustain or fuel the probiotics. Working together, prebiotics and probiotics achieve the best gastrointestinal environment for well-being. Improved health and a stronger immune system means you can train effectively and consistently without interruption due to illness and fatigue.

The Research

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While some of the claims made about the miraculous benefits of probiotics are more than likely exaggerated, a fair amount of research does support the notion that consuming probiotics regularly can improve health, well-being and athletic performance. 

One direct benefit runners can expect from incorporating probiotics is fewer mid-run toilet stops. Leaky gut syndrome is a condition that can affect runners because endurance activities can cause the cells lining the intestinal wall to pull a part a tiny bit. The gaps between the cells allow fluids in the gastrointestinal tract to leak into the bloodstream, which can result in stomach and bowel irritability during workouts. Probiotics may be able to treat that problem by keeping those gut cells together according to some research. A study published in the Journal of the International Society of Sports Nutrition in 2012 evaluated blood samples from cyclists before and after intense exercise. It found significantly fewer leakages in the guts of the athletes who had consumed probiotic supplements for 14 weeks. In a 2019 study, marathoner runners who took probiotics for four weeks before a race experienced shorter periods of GI distress. In conclusion, probiotics might help keep you spend more time running and less time in the bathroom. 

Researchers have also suggested that probiotics may benefit athletic performance indirectly by reducing susceptibility to illness. Because running along with other endurance activities puts the body under stress, it heightens immune responses including activation of inflammation and increases in the release of cytokines. Prolonged immunity activation means that the immune system becomes overworked, and when we need it—due to exposure to, say, a virus—it isn’t able to work at capacity and fend off the virus. (This is why in periods of your training cycle which are particularly heavy, you may find yourself rundown with a cold, or a nagging illness that just won’t seem to go away.) 

By maintaining optimized function in the GI tract and reducing the negative effects typically associated with exercise-induced immunosuppression, or suppression of immune response, probiotics can keep you healthy and consistent in your training. Probiotics have been shown to increase the ability for the immune system to enact pre-intervention immune response, i.e. increasing immune response before the illness takes over. In addition, there is evidence to support that in male athletes, respiratory symptoms decrease with consumption of Lactobacillus, a bacteria strain found in many probiotics. Notably, however, female athletes did not experience a decrease in respiratory symptoms to the same degree, and in some cases, instead had an increased symptomatic response. 

Probiotic Shopping Guide

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Here’s what to look for on the label when shopping for probiotics:

Live and active cultures. For probiotics to have any beneficial effects they need to reach the intestine alive and in sufficient numbers. Some products may contain cultures in insignificant amounts—or may have at some point contained cultures that have since been destroyed during the manufacturing process. For a product to claim it has live and active cultures it needs to show it has more than 100 million bacteria per gram at time of manufacture.

Culture count. Ingesting 1 billion CFUs (colony-forming units) per day is helpful for people trying to simply maintain gut health; you should ingest 10 billion CFUs per day if you’re trying to reduce the severity of a gastrointestinal illness.

Culture specificity.  Some probiotics work best for specific illnesses, so variety is better. Look for one that lists multiple culture strains.

Pills or food? During times of stress—increased training load, family/work pressures, illness—it might be prudent to increase your consumption of beneficial bacteria, and you may need to supplement with pills or with specialty probiotic “shots” such as Yakult, DanActive or Good Belly Shots. Bacteria can also be concentrated and packaged into pills or tablets for an even greater concentration of CFUs. Strains and strain count vary greatly, as does recommended dose, so check labels carefully.

TIP: Because bacteria are sensitive to heat and light, many probiotics are found refrigerated and must be stored chilled, while others have been stabilized to be effective even at room temperature. Check the “use by” dates and use within the specified time for efficacy.

A version of this article first appeared on Triathlete.

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