As an athlete, your nutritional needs are different than the average person’s needs. Regardless of your performance level – professional athlete or an athletic professional – you could be holding a full-time job while training, eating a special diet on a schedule, and sleeping as much as you can to be better at your sport. 

However, your gut health may be limiting your abilities to perform at your desired level. Without giving proper attention to your gut, you might be suffering from “leaky gut” and not even know it.

What is going on?

Leaky gut syndrome is a condition in which the gut’s thin mucosal barrier – which absorbs nutrients while preventing large molecules like bacteria, toxins, and germs in the gut from entering the bloodstream – becomes less effective.

Leaky gut syndrome – which is medically referred to as intestinal hyperpermeability – allows these unwanted molecules to leak from your gastrointestinal tract into your bloodstream, which can adversely affect your health and compromise your performance. 

Having a leaky gut can escalate into more serious health issues, such as systemic inflammation, joint pain, impaired thyroid function, malabsorption, other issues with digestion, and endotoxemia.

You could be experiencing the early signs of leaky gut if you have a symptom as vague as fatigue, which could be related to chronic electrolyte imbalance. But usually the symptoms are more noticeable, such as diarrhea, cramps, nausea, and vomiting.

These symptoms can come on acutely and last a few hours, like during a marathon or other event, or they can linger for days or weeks following a strenuous event that caused major insult to your GI tract.

A medical doctor who has worked with many Ironman triathletes says, “It’s usually not one event that causes GI tract insult. Many athletes erroneously think overconsumption of simple carbohydrates or improper hydration is what prompts leaky gut during a race.”

While race day is crucial to nailing your nutrition plan, the training and nutrition leading up to event day is just as important. How you care for your gut during training will enable you to manage and tolerate the stress both during the event and while you are recovering. 

Which athletes are most susceptible?

As an athlete or as an especially active individual, you, along with millions of others, are susceptible to leaky gut syndrome because of the nature of physical activity.

Exercise, as soon as it begins, and with increasing intensity, naturally shunts your blood flow (and its oxygen, nutrients, and ability to clear waste products) away from your stomach and intestines and toward the working muscles to facilitate the movement you are undertaking, a process often referred to as hypo-perfusion.

This reduced blood flow in and around the tissues in the stomach can cause chaos with these cells, especially if you are continuously feeding your gut with fluids and food while minimal digestion is occurring.

The GI tract can become even more permeable while running or engaging in other sports that have repetitive up and down mechanical motions. A hot environment can also exacerbate these effects. An athlete who is doing very intense exercise-to-exhaustion (like HIIT training or Cross-fit) or long duration/endurance exercise is most susceptible.

However, overtraining, under-recovering, or doing any exercise that occurs without proper gut attention can put you at risk.

Other factors that involve gut bacteria or hormone imbalances can increase your risk for gut permeability issues, such as taking an antibiotic, not producing enough digestive enzymes or hydrochloric acid in your stomach to break down foods, poor blood sugar control, stress, pregnancy, or menopause.

Why should I care?

A medical doctor who regularly works the tents at Ironman triathlons reports that in a race where 400 athletes enter the medical tent, he is not surprised to see half of them with nausea, cramping, and vomiting.

This doc says that whereas these triathletes present with symptoms that can result from a variety of root causes, in general, “the GI distress is 99 percent debilitating and race-ending.”

And following a GI insult and through recovery, the GI tract can be so disrupted that desired nutrients aren’t absorbed.

Leaky gut can manifest itself in a few complicated and challenging ways for athletes during or after an event, including as fatigue, electrolyte imbalance, dehydration, constipation/diarrhea, cramps, and decreased nutrient availability for bone, tendon, and joint health, muscle repair, and immune function.

In addition, the delicate gut-brain axis can be affected too, resulting in insomnia, changes in appetite and weight, depression, and more.1

How to manage gut health

Damage has already been done to your GI tract if you are in the middle of a sporting event hunched over with cramps or vomiting. The key to avoiding this situation is to prophylactically take care of your gut during training. 

No need to stop training.

Your body might need a little extra time to recover between workouts, or you might need a week or so of less intense training. Switch up your regimen with some yoga, lap swimming, or other less intense movements to give your muscles and your gut time to repair and heal. In particular, be sure to get plenty of sleep and support your body with nutrients, amino acids/proteins, and water.

Eat an anti-inflammatory diet.

Depending on your goals, sport, and training regimen, you could benefit from a diet that helps you decrease overall gut inflammation. A Mediterranean Diet, a ketogenic diet, intermittent fasting, a FODMAP program, or a simple whole foods diet are a few options to consider. Work with a dietitian to figure out your calorie, macronutrient, and micronutrient needs.2

Fix your damaged gut lining.

Minimize “time lost” from training by fixing the daily damage in your gut, thus maintaining its health through training and reducing your risk for post-event upper respiratory tract infections, common colds, and other acute sicknesses.

Thorne’s EnteroMend® combines the mucosa-protective effects of L-glutamine (an amino acid that lines the gut and is used for energy production during exercise) with highly absorbable botanical complexes that provide a unique amino acid/botanical formula that supports overall intestinal health.* EnteroMend contains: 

  • Meriva® and Casperome® (curcumin and boswellia phytosomes that enhance absorption), to help maintain a healthy inflammatory response in the GI tract.* 
  • DaltonMax 700®, a unique aloe extract with 200:1 potency, that soothes intestinal mucus membranes.*
  • SunFiber®, to promote healthy gut flora, normal butyrate levels, and bowel regularity.* 
  • L-glutamine, to decrease intestinal permeability.*

Maintain healthy gut lining and bacteria balance.

Just like with exercise, consistency is the key to maintaining the desired level you want to be at. Consider the timing and daily intake of foods and nutritional supplements that support gut health maintenance.

Curcumin is an antioxidant flavonoid that helps maintain the body's normal inflammatory response through optimization of cytokine production.* Thorne’s Meriva is a curcumin supplement that is 29-times better absorbed than ordinary curcumin.*

Athletes should consider a probiotic supplement that suits their unique needs. Thorne’s FloraSport 20B® provides GI support for individuals who have high demands on their digestive tract or their immune function due to travel, athletic training, competition, and chronic stress.*

Support proper digestion.

Help the food you eat move through your GI tract so it doesn’t linger in any one section of your intestines. Low-intensity stretching or moving will facilitate gut peristalsis while blood is still available to the GI tract.

Digestive enzymes help your body metabolize and absorb what it needs from the carbohydrates, proteins, and fats you eat. Fiber and fluids, especially water, will help move the waste that is left over.

Train your gut while you train for your sport.

During training, consume the same volume and calorie intake as you will during an event. These “practice runs” are particularly important for longer distances, where you might be consuming thousands of calories and multiple liters of fluid.

Schedule the timing of meals and snacks before, during, and after high-intensity workouts too, because this can be just as difficult to nail down.


1.    Clark A, Mach N. Exercise-induced stress behavior, gut-microbiota-brain axis and diet: a systematic review for athletes. J Int Soc Sports Nutr 2016;13:43.

2.    Conlon M, Bird A. The impact of diet and lifestyle on gut microbiota and human health. Nutrients 2014;7(1):17-44.