A new study (Scheiman et al., 2019) by researchers affiliated with Harvard Medical School (HMS) provides the first evidence that a specific gut bacteria called Veillonella is correlated with increased aerobic exercise capacity in humans and mice. These findings were published June 24 in the journal Nature Medicine.

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The researchers speculate that Veillonella might play a role in enhancing performance via the metabolic conversion of exercise-induced lactate into propionate, which is a short chain . Interestingly, the researchers didn't find gut bacteria belonging to the genus Veillonella in the microbiome of "insufficiently active" sedentary people. (Blogger's note: I first reported on the sports-related gut microbiome research of Jonathan Scheiman and colleagues at HMS in August of 2017—this is a follow-up post.)

"Having increased exercise capacity is a strong predictor of overall health and protection against cardiovascular disease, diabetes, and overall longevity," co-author Aleksandar Kostic of Harvard's Joslin Diabetes Center said in a recent statement. "What we envision is a probiotic supplement that people can take that will increase their ability to do meaningful exercise and therefore protect them against chronic diseases, including diabetes."

This brief video from the Joslin Diabetes Center sums up the significance of the Veillonella findings:

How was this research conducted? In the first phase of this study, Kostic and colleagues collected stool samples from a cohort of 15 Boston Marathon runners and ten "non-runners" (who were a control group) one week before the marathon and one week after the race.

The microbiome analysis showed that the genus Veillonella had become more abundant in marathoners' GI tract one week after running 26.2 miles. Notably, this gut bacteria has the unique ability to gobble up lactate, which is a metabolite associated with exercise-related fatigue. These results were reproduced in another cohort of 87 elite-level athletes.

For this study's second phase, the researchers conducted experiments in mice. More specifically, the strain of Veillonella collected from one of the human marathon runners was administered to 16 mice. The researchers found that the mice who were given this particular bacteria showed a 13 percent improvement on a laboratory treadmill test in comparison to a "Veillonella-free" control group.

Note: Before you read any further, it's important to emphasize that these findings do not suggest that Veillonella is a magical performance-enhancing gut microbiome that will give you superhuman strength and endurance. Microbiome research is a burgeoning field that is still in its infancy; these preliminary findings should be viewed with healthy skepticism until clinical trials are conducted and we know more about a possible causal link between Veillonella and enhanced athletic performance.

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In an interview by Khari Thompson of WBUR about this recent study, Kostic was asked: "Are you concerned that some runners won't wait for the clinical trial and will try to manufacture their own supplements? And what are the risks of that?" He responded,

"I definitely do worry a little bit about what I see sometimes with do-it-yourself fecal microbiota transplants. I think the risk inherent is too great to be worth any potential benefit. The real consequence will only really be seen if we can demonstrate safety in humans for Veillonella. As far as using propionate itself, that comes with risks. It's is an acidic molecule and could certainly have detrimental effects that we don't know about. So all of this is to say I don't recommend [taking] action today, but certainly, people are working hard to try to manufacture this in a safe way in the future."

Introducing foreign gut bacteria or microbiota into your body carries potential risks. For example, on June 13, 2019, the FDA issued an "Important Safety Alert Regarding Use of Fecal Microbiota for Transplantation and Risk of Serious Adverse Reactions Due to Transmission of Multi-Drug Resistant Organisms."

Also, over-the-counter, mass-produced probiotics can have adverse side effects. See, "Back-to-Back Studies on Probiotics Set Off Alarm Bells," "Unexpected Findings Cause Scientists to Rethink Probiotics," "In a Brain Fog?" Probiotics Could be the Culprit."