There is more and more evidence that your gut health can impact more than just your digestive system. The bacteria in your intestines have been shown to influence our mood, our hunger and satiety, and our immune function.

But one area of emerging research has also shown that these bacterial species can affect our performance during exercise. This has led to studies looking at whether probiotic supplements can lead to improvements in performance and used as an endurance supplement.

A recent review (1) of all probiotic studies to date found that, from 24 studies, while only 7 reported significant improvements in performance following probiotic supplementation, there were big differences in study design and it was suggested that effects may be specific to individual probiotic supplements - they are not all the same.

There is now new evidence that they could have direct benefits for those competing in endurance events such as marathons and triathlons.

While the LAb4 Probiotics have been used in numerous clinical studies assessing their use for weight loss, immune function and stress and anxiety (see our Lab4 basics blog), there is now new evidence that they could have direct benefits for those competing in endurance events such as marathons and triathlons.

The first evidence of our probiotics being beneficial as an endurance supplement was shown in a study published in 2014 (1). A group of runners were recruited to perform trials where they were asked to run for as long as possible on a treadmill in the heat. Then, one group supplemented with Lab4 probiotics while the other group took a placebo. After runners had supplemented with Lab4 probiotics for 4 weeks and asked to, they were able to run for ~15% longer compared to when they had taken the placebo. 

In 2016, the next piece of evidence was published showing that probiotics were beneficial to athletes taking part in an Ironman Triathlon (2.4 mile swim, 112 mile cycle, and 26.2 mile run) (2). Participants supplemented with probiotics or placebo for 12 weeks. Those taking probiotics had a 10% quicker overall race time than those on the placebo - with a particularly quicker cycle time – although this did not reach statistical significance.

Lab4 probiotics seemed to reduce the gut symptoms experienced by some endurance athletes

Gut symptoms like bloating, nausea, stomach/intestinal pain or discomfort, cramping, headaches, dizziness, constipation and diarrhoea were assessed and severity scores during training were significantly lower in the Lab4 probiotic groups compared to the placebo group.

The Marathon des Sables is a multi-day ultramarathon in the Sahara desert that is often called the toughest race on the planet. In a 2017 study (4) runners supplemented with either probiotics or placebo for 12 weeks before heading to the desert. Although not statistically significant, runners had an overall race time that was 12% quicker after supplementing with Lab4 probiotics compared to placebo.

One of the most recent research to have examined the effects of Lab4 probiotics on endurance performance was published in. In the study runners supplemented with Lab4 probiotics or a placebo for 4 weeks, before competing in a marathon race around a 400m athletics track (that’s over 100 laps)  in controlled conditions. The key difference between this study and previous studies was that the researchers looked to control as many different factors as possible. Runners were all supplied with the same diet for the day before the race and they all consumed the same breakfast - meaning any differences seen in the measures were not because of differences in their diet. All runners were also required to take on water and carbohydrates during the race in amounts that fit best practice guidelines in order to try and limit dehydration and help prevent the runners from "hitting the wall".  

Compared to placebo, the probiotic group were able to maintain their speed at the end of the race, while the placebo tended to slow down.

The probiotic group saw reductions in gut symptoms during the weeks leading up to the race. They also reported less severe symptoms such as bloating and the urge to go to the toilet, during the marathon itself. This, in turn, saw that, compared to placebo, the probiotic group were able to maintain their speed at the end of the race, while the placebo tended to slow down.

Benefits of LAB4 probiotics on endurance performance:

• Reduced gastrointestinal symptoms such as bloating, feeling the need to go to the toilet, and stomach cramps during training and competition
• Improvements in exercise performance - from exercise lasting around 30-40 minutes all the way through to multi-day races
• Performance benefits may come from reductions in symptoms but other mechanisms may be at play

All of the studies presented here have shown that probiotics had different benefits, compared to placebo. Many saw reductions in gut symptoms - something that can plague endurance athletes or force them to drop out of races. And while it was not always statistically significant, many of these studies reported some form of performance improvement in those taking the probiotics.

However, As with most research, this is just the beginning and there are plenty more questions that need answering. Furthermore, no supplement will ever substitute getting the basics right with your training and nutrition. 

References

1 - Jäger, R., Mohr, A. E., Carpenter, K. C., Kerksick, C. M., Purpura, M., Moussa, A., ... & Antonio, J. (2019). International society of sports nutrition position stand: probiotics. Journal of the International Society of Sports Nutrition, 16(1), 1-44.

2 - Shing, C. M., Peake, J. M., Lim, C. L., Briskey, D., Walsh, N. P., Fortes, M. B., ... & Vitetta, L. (2014). Effects of probiotics supplementation on gastrointestinal permeability, inflammation and exercise performance in the heat. European journal of applied physiology, 114(1), 93-103. 

 3 - Roberts, J. D., Suckling, C. A., Peedle, G. Y., Murphy, J. A., Dawkins, T. G., & Roberts, M. G. (2016). An exploratory investigation of endotoxin levels in novice long distance triathletes, and the effects of a multi-strain probiotic/prebiotic, antioxidant intervention. Nutrients, 8(11), 733.

4 - Suckling, C., Roberts, J., Peedle, G., Gordon, D., Marshall, H., Taylor, L., & Roberts, M. G. (2016). Probiotic Supplementation and Gastrointestinal Endotoxemia Before and After the Marathon Des Sables. Medicine & Science in Sports & Exercise, 48(5S), 249-250.

5 - Pugh, J. N., Sparks, A. S., Doran, D. A., Fleming, S. C., Langan-Evans, C., Kirk, B., ... & Close, G. L. (2019). Four weeks of probiotic supplementation reduces GI symptoms during a marathon race. European journal of applied physiology, 119(7), 1491-1501.