The microbiome is a big area of study and is very complex and very complicated. I don’t think we currently know all that much about it. In saying that, I think there are some things we can take away from all the research people are doing to see how / if they relate to ourselves and our athletes and try to make adjustments accordingly.
This study, The Athletic Gut Microbiota, goes into great detail in regards to what impacts the gut microbiome of athletes, some of the beneficial changes seen in athlete’s microbiome compared to sedentary people, and some of the negative consequences athletes can face when training really hard in regards to their gut health. It also highlights how quickly the microbiome can change, especially in response to dietary changes and in the type of exercise performed.
In general, it has been shown that athletes have more diversity of gut bacteria. Diversity is thought to be beneficial to health at this point by many experts. Active individuals microbiota also display more health promoting bacterial species.
They also found that athletes produce more short chain fatty acids which are associated with “enhanced muscle turnover (fitness) and overall health than less active individuals”. Dr. Marc Bubbs explains in his book Peak, that SCFA propionate is beneficial for the integrity of your gut wall because it increases the number of tight junction proteins and down-regulates pro-inflammatory TNF-alpha in colon cells. He also mentions that butyrate is burned in the mitochondria of intestinal cells to produce ATP, is a key regulator of mitochondrial function, and supports fatty acid oxidation, improving your fuel efficiency, which is crucial to all athletes.
Another key point highlighted in the study “The athlete/exercise-associated gut microbiome may possess a functional capacity primed for tissue repair and a greater ability to harness energy from the diet with increased capacity for carbohydrate metabolism, cell structure, and nucleotide biosynthesis”.
The type of diet the athlete eats has a large impact on the makeup of the microbiome. For example, bacteroides levels can increase on a higher fat, higher protein diet, they tend to be beneficial as they are capable of breaking down pretty much everything in the diet. “Protein intake appears to be a strong modulator of microbiota diversity, with protein supplementation, such as whey, showing potential benefits that need further study in humans.”
“Higher intake of carbohydrate and dietary fiber in athletes appear to be associated with increased abundance of Prevotella.” Prevotella is generally higher in endurance athletes such as elite cyclists.
Changes in the diet can lead to changes in the microbiome within 24 hours.
The type and intensity of the exercise also plays a role in the composition of the microbiome. It doesn’t matter if athletes are meat eaters, vegetarians, or gluten free or not, the type of exercise they perform, anaerobic or aerobic, seems to show a more similar pattern between their microbiome’s. So, athletes in anerobic sports will have similar gut microbiome profiles, for example.
“Nearly all studies included in this review have shown positive correlations between gut taxa and exercise. Overall exercise appears to enrich microbiota diversity, stimulate the proliferation of bacteria which can modulate mucosal immunity, improve barrier functions, and functional pathways capable of producing substances (e.g., butyrate and propionate) that can increase performance and health”.
Overtraining or excessive exercise has been shown to negatively impact the athlete and lead to leaky gut. “Prolonged excessive exercise has a deleterious influence on intestinal function, including increased intestinal permeability.”
The longer the duration of the event or training session, the more damage seems to be done to the gut. In Dr. Marc Bubbs book he mentions a study where 87% of ultramarathon runners had occult blood in their stool post-race.
Too many sports drinks and too many carbs from cereals, breads, and processed foods for example, also impact the gut negatively, leading to inflammation.
“Food intolerance and undetected gut issues impede squat performance” – Charles Poliquin.
The reason for this is that gut issues create inflammation and this inflammation inhibits core contractions. Because of this you are unable to create as much intra-abdominal pressure as you could, which means you can’t brace as well throughout your lifts. This decreases performance and increases the risk of injury.
Other common things that can impact gut health of athletes are chronic stress, antibiotics, and travel. These are all things to take into consideration when preparing your athletes.
