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Harvard study links gut bacterium to athletic performance

Researchers at Harvard University have found that top-performing rodents and athletes share high levels of gut bacterium Veillonella.

Athletes pumping iron or pounding the pavement in pursuit of a performance boost could be doing it harder than necessary. According to a US study, microbes may be able to spare them some perspiration.

Harvard University researchers have linked a strain of bacteria in the gut microbiome to a 13% increase in athletic performance.

Discoveries about the complex population of human gut bacteria have until recently focused mainly on its effect on health and disease. However, there is much more to understand about the microbiome, such as the large variances in gut bacteria between healthy people of different races and ethnicities. How exercise might alter the microbiome of elite athletes and potentially influence their physical abilities is also relatively unknown.

The Harvard study involved 15 athletes who ran the 2015 Boston Marathon, along with 10 sedentary controls, and set out to identify gut bacteria associated with “athletic performance and recovery states”.

Stool samples were collected daily for up to a week before and a week after the marathon. They showed significantly higher levels of the bacterial genus Veillonella after exercise than before and that the runners had higher levels of the bacterium than the non-runners.

To work out whether Veillonella had any effect on performance, the researchers resorted to mice. A control group was given the bacterium Lactobacillus bulgaricus and the treatment group was given Veillonella atypica taken from one of the runners. The mice given Veillonella had significantly longer maximum run times than the other mice. On average, they ran for 13% longer.

How can one genus of bacteria so dramatically affect an animal’s performance? Delving into the life of Veillonella provides some clues.

For a start, Veillonella don’t ferment carbohydrates like many of the other bacteria found in the gut. Instead, their preferred energy source is lactate, a substance produced by the body during exercise or in response to injury or illness.

For years, lactate was thought of as an undesirable by-product of exercising muscles. However, it’s now recognised as a positive response to metabolic stress.

After injury, such as damage to muscle cells through exercise, adrenaline activates the sympathetic nervous system, which starts lactate production. This is much like refuelling a racing car, say researchers.

The lactate is then available to the body as a fuel source to support blood-sugar levels, and as a signal for metabolic adaptation to stress.

The lactate produced by the exercising mice was found to have crossed from their circulation into their gut, where it was converted by the Veillonella bacteria into propionate, a short-chain fatty acid, which then re-entered the circulation, providing a performance-enhancing fuel source. The researchers surmise that the same mechanism is at work in top human athletes.

It’s early days yet in this line of study. Although the performance boost hasn’t yet been demonstrated in humans, an observational study has found similarly high levels of Veillonella among ultra-marathoners and Olympic-trial rowers.

That’s good enough for a handful of the Harvard research team who are already trying to commercialise their findings. They’ve reportedly left the university and founded a start-up company that is developing a prototype probiotic supplement containing Veillonella extracted from elite athletes.

This article was first published in the August 31, 2019 issue of the New Zealand Listener.