Something really does make marathoners different than the rest of us. They appear to have unusually high levels of a bacteria in their digestive tract that may help them go the distance, a new study suggests.

We all have a unique community of bacteria, fungi, and other microbes living in our intestines known as the gut microbiome, which aids digestion, regulates our immune system, and helps protect against certain diseases.

Even though no two people have the same gut microbiome, researchers wanted to see if there might be similar bacteria in the guts of marathoners and elite athletes that could give them a leg up in competitions.

For the study, researchers tested stool samples of 15 athletes a week before and after they ran the 2015 Boston marathon, and compared their microbial makeup to that of 10 nonrunners. The athletes’ samples contained higher levels of the bacteria Veillonella atypica after workouts and even higher levels after running a marathon.

Veillonella is a microbe that metabolizes lactate — the byproduct of a hard workout that makes muscles ache — into propionate, a short-chain fatty acid that gives us energy.

Normally, the body gets most of its energy from glucose. But during intense exercise, lactate accumulates in the body because the muscles aren’t able to completely break down the glucose to use it for fuel. Most of this lactate gets processed in the liver, but some of it crosses into the gut, where it gets consumed by Veillonella.

To test whether the increase in Veillonella in runners revved up production of propionate in their guts, researchers gave mice the same strain of microbes. Mice given Veillonella atypica ran 13 percent longer in treadmill tests than mice who didn’t get this bacteria.

“The gut microbes can contribute to exercise endurance,” says Alexander Khoruts, MD, medical director of the microbiota therapeutics program at the University of Minnesota in Minneapolis, and one of the authors of the study, published in June 2019 in the journal Nature Medicine.

While the results raise the question of whether people might one day be able to take a pill containing Veillonella atypica to boost athletic performance, it’s impossible to answer this from treadmill tests in mice, says George Church, PhD, a coauthor of the study and professor of genetics at Harvard Medical School in Boston.

Dr. Church is also cofounder of Fitbiomics, a company spun out of the Wyss Institute for Biologically Inspired Engineering at Harvard, which is aiming to one day sell probiotics to boost athletic performance.

“Clarity on the implications will have to await … trials in humans,” he says.

While that might be a way off, you can always strive to improve your gut microbes. Research suggests that you can increase healthy microbes in your gut by:

“Increasing dietary fiber and maintaining a diet high in fruits and vegetables is the easiest way to augment a healthy, robust gut microbiome,” says Jessica Allegretti, MD, a gastroenterologist at Brigham and Women’s Hospital in Boston, who was not involved in the study.