Does Gut Health Impact on Performance?

Over the last 12 months the topic of gut health has also been highlighted as an area of interest for endurance athletes, to assist them in working at their optimal level through the use of fermented foods.



Although it is well documented that regular exercise is healthy for us it is not often highlighted that athletes and in particular endurance athletes, are more susceptible to illness. High intensity and long duration training not only increases the release of the stress hormone cortisol, but also impacts on immune system function, putting athletes at a greater risk of upper respiratory tract infections (UTIs).

Gut health is not only important to assist with the digestion and absorption of key nutrients that fuel performance, but also has an indirect impact on both training and racing. Maintaining a healthy gut not only helps to prevent nausea and gastro-intestinal upset, which can be triggered during high intensity exercise, but additionally poor gut health can also have an adverse impact on ones immune system as well as increasing the circulation of inflammatory chemicals throughout the body.

Research in the area of gut health over the past decade has shown some modest results particularly when looking at the impact of probiotic supplementation on reducing the frequency, duration and severity of upper respiratory tract infections in endurance athletes. However; there have been more promising results with regards to gut microbiome, otherwise known as the microorganisms that inhabit ones digestive tract, and the role that these play in nutrient absorption and reducing inflammatory markers which impact on both performance and the rate of recovery.

With the gastrointestinal tract tipped to be home to between 300-1000 different species of ‘gut flora’ or 100 trillion bacteria; the relationship between the gut and an athlete’s health is a complex one, with around 80% of the immune system predicted to exist in the gut. As a result, the health of an endurance athlete is closely connected to their digestive system with strong evidence indicating that a diet high in probiotics can improve an athlete’s immune function, decrease gut permeability (aka ‘leaky-gut’) and reduce inflammatory markers. [1]

The most effective way to promote positive gut health is through the consumption of foods that are packed with probiotics. Fermented foods such as Kefir, Tempeh, Miso, Kimchii, Sauerkraut, Kombucha, Natto and some natural yoghurts are not only rich sources of probiotics but also high in some B group vitamins; which play a vital role in energy production, and assists with the production of Vitamin K; a fat soluble vitamin that not only helps to protect the heart but also plays a key role in preventing osteoporosis and development of cancer cells. While probiotics are available in a tablet form the best sources occur naturally in fermented foods and through the regular consumption of these products as a part of a healthy balanced diet, endurance athletes have the capacity to optimize their glut flora and have a direct and positive effect on their health.

1. Gleeson M, Bishop NC, Struszczak L. Effects of Lactobacillus casei Shirota ingestion on common cold infection and herpes virus antibodies in endurance athletes: a placebo-controlled, randomized trial. European Journal of Applied Physiology. 2016;116:1555-1563.

Lori is the owner of Raw Energy Nutrition and consults to various organisations on sports science, nutrition and public health... so she knows what she is doing. Importantly Lori loves to ride, but when she's not on the bike or working you'll find her doing yoga or pilates, her head buried in books or catching friends for a chai.