Sports Nutrition & Gut Health

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Welcome back to our series on Sports Nutrition. In this week’s article on Sports Nutrition & Gut Health we will look at the role of the gut (our favorite topic!) in Sports Nutrition. 

We have written extensively about gut health, starting with our series of articles on the Gut-Brain Axis. We also mention the gut in most of our articles. It is so critical to overall health that it cannot be avoided. This week we are going to look at gut health and how it specifically relates to athletic performance. There is some exciting new research being done on this topic and we will present it to you here.

** Please note: If you want the longer more detailed version of this article, then please click here **

Very few studies have looked at differences in performance and the role of the gut. This is an area that may be able to provide an edge for athletes, who will usually look for any possible advantage to enhance performance (Hughes, 2020).

A good example of a well-known athlete improving gut health and experiencing a tremendous uptick in performance is the top ranked, elite tennis player Novak Djokovic. Djovokic was a strong tennis player but suffered from symptoms, such as difficulty breathing and fatigue, during championship matches for years. It was thought that the issue was due to his level of fitness but it turned out that he had digestive issues. In 2010, Djokovic went gluten- and dairy-free and dramatically improved his performance (Campbell, 2019). He worked with a Nutritionist and identified that he was sensitive to both gluten and dairy (Campbell, 2019). He eliminated both from his diet and within 12 months, became healthier, more energetic and mentally sharper (Campbell, 2019). Since then, he began winning more Grand Slam tournaments and has dominated men’s tennis ever since.


Athletes have a different gut microbiome composition from those of sedentary people (Jäger R, 2019). Differences are due to the amount of exercise they do, the effect of exercise on the gut microbiome, the amount of protein they consume, the effect of diet & nutrition on the gut microbiome and the effect of the gut microbiome on performance (Hughes, 2020) and (Jäger R, 2019).


The key differences of the gut microbiome of athletes compared to non-athletes are linked to enhanced fitness (Jäger R, 2019).

  • Athletes have higher microbiome diversity, meaning they have a greater variety of different types of gut bacteria. More diversity is associated with better health.
  • Athletes have a higher number of health-promoting bacteria in the gut.
  • Athletes have more short chain fatty acid (SCFAs), which are produced by microbes in the gut (Jäger R, 2019).
  • Exercise increases the Bacteroidetes-Firmicutes ratio.
  • Exercise can reduce inflammation (Mailing LJ, 2019).
  • Exercise increases gut motility and bile acid (Mailing LJ, 2019). Low motility and/ or low bile acid secretion contribute to gut dysbiosis.
  • Overall, exercise represents a hormetic stressor to the gut that stimulates beneficial changes and improves the long-term resilience of the gut barrier (Mailing LJ, 2019).

Interestingly, most gut bacterial strains and SCFAs that increased with exercise decreased once exercise was stopped (Mailing LJ, 2019).


  • The gut microbiome is vital for the proper function and development of the body (for energy metabolism, the inflammatory response, stress resistance, oxidative stress), but it is not clear which are the key species and whether the microbiome's overall function is more important than any individual member of the microbiome in terms of impact on the exercise response (Mach N, 2017).
  • Endurance swimming time was longer for mice with a gut microbiome vs. that of germ-free mice (i.e. with no gut bacteria), suggesting that gut bacteria composition is crucial for exercise performance (Mach N, 2017).
  • In young adults, overall microbial diversity and abundance of butyrate-producing bacteria were positively correlated with cardio fitness levels (Mailing LJ, 2019).


Probiotics can improve performance in athletes and physically active individuals, although the results are mixed (Jäger R, 2019).

The most obvious benefit of probiotics on athletic performance is the impact on the immune system (Jäger R, 2019).

Strenuous and prolonged exercise can also be stressful for the gut.

In athletes, one study found the administration of Lactobacillus and Bifidobacterium strains help to maintain general health, improve immune function, help gut permeability, reduce oxidative stress and better obtain and absorb energy from plant-carbohydrate sources (Mach N, 2017).

Whilst research on gut health and athletic performance is still in the early phases, it is clear that exercise changes gut health for the better. It is also clear that optimizing gut health will improve performance, as well as general health. In order to be in the best health possible, improving gut function is an essential area to target with an experienced FM practitioner.

What you can do to help improve gut health for athletic performance?:

Add a probiotic blend with Lactobacillus and Bifidobacterium strains, like our Good Gut Bugs + SB product (available through our clinic if you text 720-722-1143 for more info)

Do an elimination diet for 30-90 days and then re-introduce foods one at a time to check for negative reactions (1 food every 3 days)

Gluten, dairy, corn, soy and eggs are all common allergens so start by eliminating these first

To take it a step further, also eliminate nuts, fish and shellfish

Eliminating nightshade vegetables, seeds, all grains and legumes / beans can be highly effective for identifying food sensitivities (but of course is fairly restrictive while doing it)

When re-introducing, it is important to add back just 1 food every 3 days and if there is a negative reaction, remove that food for at least another few months and test it again in the same way. If there is still a negative reaction it can be removed long-term

** Please stay tuned for next week’s article on Sports Nutrition **

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