Is gut health the performance hack you’re missing out on?

It’s now widely known that the human gut microbiome underpins good health thanks to its effect on vitamin absorption, digestion, mood and immunity. Less scientific research has gone into impact the gut microbiome, which is made up of trillions of microbial cells within the intestines, has on endurance sport performance. However, the evidence implies that a healthy gut, as defined by high microbial diversity, may help us swim, cycle and run faster for longer. 

Before looking at its potential performance benefits of gut health, it’s reassuring to know that because we exercise regularly, we should have healthier than average guts. Authors of a review into “The Athlete Gut Microbiome and its Relevance to Health and Performance” note that moderate levels of exercise seem to benefit gut health in a J-shape curve. More intense and prolonged exercise appears to impair gut health. This is something many of us will have experienced after a hard race or training block. 

Better endurance

In the same review, researchers also highlighted studies that detected high levels of certain microbes in the faeces of marathon runners. When fed to mice, another study found that these microbes improved their running performance, possibly as a result of increased lactate metabolism. Levels of short chain fatty acids (SCFAs), produced by microbes, have also been linked to humans’ VO2 max in a separate study. Other scientists have speculated that these SCFAs could also improve endurance by acting as a fuel source. 

Weight lifting gains

Studies on mice suggest that a healthy gut microbiome boosts adaptations from resistance training. Another type of gut-friendly bacteria corresponded to faster 3,000m times in Japanese runners, as the authors of “Gastrointestinal function and microbiota in endurance athletes” point out. 

Watch this space

In their systematic review into the “Performance Gut” published in the Frontiers in Sports and Active Living, the authors conclude that the “gut microbiome emerges as a potentially determining factor for optimising athletic performance and health”. That said, they underline the topic remains poorly understood. For now though, it seems that we have nothing to lose by concentrating on gut health. At least it will improve our general wellbeing if not our performance. Here’s a reminder of how to do so. 

How to keep your gut healthy

Eat lots of carbs

The high-carbohydrate diet endurance athletes are encouraged to eat appears to be good for microbial diversity. On the other hand, a diet higher in protein and fat looks to be less beneficial, possibly due to lower fibre consumption. 

Be gut-friendly 

Because researchers underline that nutrition has a bigger role to play in gut health than exercise, it seems logical to prioritise gut-friendly recipes, for example containing fermented foods, in our weekly diet. 

Don’t train too hard

Scientists believe that higher intensity exercise can harm the gut, possibly by diverting blood away from the intestines. Dehydration and heat stress appear to have a similar effect. Of course, some HIIT training is essential. But it would be wise to minimise the dose while avoiding getting too dehydrated and hot too often. 

Supplement with probiotics 

Since nutritionist Rob Hobson questioned the benefit of probiotics on athletic performance in 2022, subsequent reviews and meta-analyses have supported their use. Consuming a single strain of probiotics for about four weeks improves aerobic exercise performance, according to an overview of existing evidence by Santibañez-Gutierrez et al.