Feb 17, 2025The athlete’s guide to gut health
Stomach discomfort is an unfortunate reality for many high-level athletes. Ranging from acid reflux to constipation or diarrhea, discomfort presents in a multitude of ways and can negatively impact athletic performance.
Studies have shown that nearly 50% of athletes experience some form of gastrointestinal (GI) distress symptom throughout the training seasons. While the problem is widespread and can be seriously limiting, research is beginning to uncover ways athletes can use nutrition to manage and reduce these symptoms. One promising approach? Focusing on gut health and tailoring the diet to support a balanced gut microbiota.
Our gastrointestinal tract is made up of more than 100 trillion microorganisms, all working together to perform vital tasks. It is responsible for several functions including nutrient uptake, utilization of energy, and vitamin synthesis. In simple terms, the GI tract breaks down food, turning it into energy for our bodies to use to perform activities. Pretty essential, right?
There is a clear and direct relationship between exercise and gut health modification. While engaging in activity, our autonomic nervous system is activated and works by increasing and circulating stress hormones, such as cortisol, epinephrine, norepinephrine and catecholamines, throughout the body. As a result, blood flow is reduced to the GI tract which ultimately leads to damaged gut barriers, nutrient depletion, and inflammation. Due to these effects, in combination with an athlete’s unique nutritional needs, the gut microbiome of an athlete is typically more diverse than that of the non-athlete, containing more health-promoting bacteria. With the high activity demand, the gut adapts. Since the athlete’s gut functions in a different way, we must approach the care of it differently as well.
So, why should gut health matter to you? Research has found that managing the bacteria in your gut can have a big impact on things like performance, recovery, and even how often you get sick. Let’s dive into how you can tweak your nutrition to reduce the risk of GI distress and help you perform at your best.
Prebiotics vs. Probiotics
Don’t be fooled by how similar these sound. These function very differently and work to achieve a different goal. Let’s start with prebiotics. They are non-digestible fibers for your gut bacteria to “eat”, in turn, promoting your overall health. In food form, certain fruits, vegetables, and whole grains can be considered “prebiotics”.
There is promising research for improving energy and cognition, bone health, and GI health, but research on prebiotics is still in its infancy. As for supplementing with a prebiotic, evidence is sparse.
Conversely, research surrounding probiotics is much more abundant. Probiotics are live microorganisms (like bacteria) that, when taken in the right amounts, can provide health benefits. Essentially, they’re the “good” bacteria that can help improve your gut health and overall well-being. The most common and widely researched probiotic strains include Bifidobacterium spp. and Lactobacilli. Research has found several health benefits of probiotics, notable ones being reducing inflammation, decreasing the risk of infection, improving nutrient absorption, increasing hormone production, and enhancing energy usage. Sounds great, right? Why isn’t everyone taking these? Well, it’s not that simple. A common probiotic supplement contains 1 billion microorganisms. Remember how I mentioned earlier that our gut is made up of 100 trillion microorganisms? A probiotic supplement is just a drop in the bucket. It takes a very calculated approach to alter such an established environment. There is a massive variation in probiotic supplements, with differences in dosages and strains. There is an even larger variation in your microbiome compared to someone else’s microbiome.
It’s difficult for researchers to standardize recommendations with such drastic differences in factors such as the participants’ baseline diet and immune status. But one thing can be agreed upon: probiotics alone are not the magic fix. If not supported with an adequate and balanced diet, probiotics may not be as effective.
Actionable Steps
So, what can you do about it? Is there hope for fueling the microbiome? Absolutely! Here’s what we know so far:
- Enhance your gut microbiota by incorporating probiotic-rich foods into your diet. Excellent choices include yogurt, sourdough bread, kefir, kombucha, sauerkraut, and miso, all of which provide beneficial strains of bacteria to support digestive health.
- Fiber is friend and foe. Fiber feeds our gut microbiota, just as prebiotics do. It is known to add bulk to our stool, keep us fuller longer, and is typically in nutrient-rich foods. However, too much fiber close to a training session can result in gas and abdominal discomfort. Choose lower-fiber foods on competition days to reduce the risk of GI symptoms.
- Meet your energy needs. An excess or deficiency in energy intake can alter the gut microbiota. Eating an energy balance promotes digestive efficiency.
- Eat a variety of produce to help maintain a healthy gut flora. Most Americans do not meet the daily recommendations for fruit or vegetables. You should aim for 2 cups of fruit per day and 2.5 cups of vegetables per day.
- Be cautious with high-fat foods around competition time. These are known to be pro-inflammatory and could result in bloating or cramping. Fat takes longer to digest, so it is best to stick to simple carbohydrates before training or competition that contain both glucose and fructose to minimize symptoms.
- Increase protein intake throughout the day! Protein plays a role in influencing microbiota diversity. However, since protein takes longer to empty from the stomach, consider limiting the amount of protein consumed immediately before a workout.
- Hydrate, hydrate, hydrate! Fluids are essential for the movement of nutrients throughout the GI tract to be digested, absorbed, and utilized.
If you find that your GI distress is interfering with your athletic performance, you are not alone, and there are actionable steps you can take to reduce the symptoms. Since every athlete’s needs are different, it’s helpful to work with a nutrition professional who can guide you in finding the right approach for your body.
Written by an American Sports and Performance Dietitians Association Registered Dietitian (RD). To learn more about sports nutrition and ASPDA, go to www.sportsrd.org.
