Home > Health & Nutrition

Study: probiotics may improve marathon performance

New research investigates how probiotics influence your gut during a marathon

There are few things worse than getting hit with sudden GI distress in the last half of a marathon. Unfortunately, it is an all-too-common scenario for runners everywhere. While there are many things runners can do to avoid this (like practicing your race-day fuelling strategy and training your gut), research shows that runners can reduce their risk for GI issues (and improve performance) by taking probiotics.

RELATED: Can probiotics prevent post-marathon sickness?

In 2019, a study published in the European Journal of Applied Physiology found that runners who took a probiotic supplement for one month leading up to their experienced a lower incidence and severity of GI symptoms during the marathon. When compared to runners who were given a placebo pill instead, the probiotic group also slowed down less during the final third of the marathon, which led the researchers to conclude that “reducing GI symptoms during marathon running may help maintain running pace during the latter stages of racing.” In other words, taking a probiotic could indirectly improve your running performance by removing a potential obstacle that would slow you down.

More recently, a 2021 study in the journal Metabolites investigated how probiotics work their magic during endurance exercise. To do this, the researchers divided 20 male runners and four female runners into two groups. One group received a multi-strain probiotic for 28 days, while the other received a placebo and at the end of the 28 days, all the runners ran a marathon around a track. Blood samples and muscle biopsies were taken before and after the race.

The researchers found several different “metabolic perturbations” between the two groups of runners after the marathon, and so concluded that a probiotic supplement may alter the way running a marathon influences your gut. In other words, taking a probiotic supplement can help maintain the integrity of your gut during endurance exercise, which reduces your chances of experiencing GI problems on race day.

RELATED: Low-FODMAP diet may benefit runners who are prone to GI distress

So should all runners be taking a probiotic supplement? It’s too early to offer any sweeping recommendations, but it does appear that supplementation, at least in the short term leading up to a race, can lessen your risk for tummy trouble. For runners who often struggle with GI distress, this may be an unexplored avenue that could help solve your problem. Not all probiotics are created equal, however, so speak with a dietitian or knowledgeable healthcare practitioner first, who can help you find the right supplement for you. Alternatively, you could try to incorporate more probiotic-rich foods into your diet, like yogurt, kefir, sauerkraut and kombucha.