James Brown, a Master’s degree student at Georgia Southern’s (GS) Armstrong campus in Savannah, recently took on a graduate assistantship that focuses on researching gut health.
The assistantship placed Brown with Waters College of Health Professions associate professor Greg Grosicki, Ph.D., in Tahoe City, California.
Under the advice of Grosicki, Brown helped collect data for a large-scale research study to see how the gut microbiome changes in athletes during the Western States Ultramarathon.
“The Western States Endurance Run represents what we like to say is like the epitome of extreme human physiology and possibly the world’s best human performance lab because we’re able to study the human being and the human condition in the most extreme circumstances,” Grosicki said.
“Besides killing someone, you really can’t get any more extreme than what these people are going through. They’re running 100 miles at 8,000 feet elevation in 110 degree heat. To really understand how the human body works when we study it in extreme conditions like this, we’re really able to glean insights that there’s absolutely no way we could recapitulate in a laboratory environment,” he continued.
The gut microbiome refers to a collection of bacteria, viruses and microbes that reside in the gastrointestinal tract. It has even been described by some as a second brain.
“There are 39 trillion bacterial cells in the gut,” Grosicki said. “To put that in perspective, our bodies are made up of 30 trillion cells, so there are actually more cells living inside of us than we are composed of, which I think is pretty cool. It makes you think, are we actually living on these bacterial cells or are they living in us? It’s pretty crazy to wrap your mind around.”
Grosicki, who began researching how gut microbiome changes as humans age during his postdoctoral work, saw there was limited research on how exercise might change the gut microbiome.
“What I’ve learned over the course of my career is that exercise is really the magic bullet,” Grosicki said. “There’s no exercise pill. It can’t be put in a pill. No one’s going to be able to ever develop it because there’s just absolutely no way to capture the therapeutic benefits of exercise in a single supplement. I wanted to know what happens to the gut microbiome when we exercise, and that’s really been one of my primary missions as a scientist at GS.”
Grosicki partnered with fellow researchers Jacob Allen, Ph.D., from the University of Illinois at Urbana-Champaign, Jimmy Bagley, Ph.D., from San Francisco State University, and Jamie Pugh, Ph.D., from Liverpool John Moores University.
The research team recruited 43 athletes to participate in order to examine how gut bacteria shifts during intense and extremely long bouts of exercise as a means to better understand the organ overall.
Data from these athletes will help Grosicki and his colleagues build upon results from 2019 when he studied a single ultramarathon runner and observed a significant shift in human gut bacteria.
“The most striking change we saw was a specific bacteria that metabolizes lactate, which is produced during exercise. The body takes that lactate and turns it into fuel that can then be put back into circulation and used by the body for exercise,” Grosicki said.
The research team collected pre- and post-race blood and stool samples, learned about each athlete’s medical history and training, looked at race-day factors, diet and more.
Additionally, having both biological male and female and varying age data from the race was important.
“Our athlete in 2019 was male and we know that biological sex can play a huge role in these physiological adaptations and the gut microbiome,” he said. “We were very intentional in trying to recruit a sample of both males and females. We’re also going to be able to look at biological sex and age. We had people in their 20s, we had some people in their 60s. We can control for these biological variables such as age and sex, and see how those may influence the gut bacteria and their response to exercise as well.”
In October 2022, Grosicki furthered this line of research at the Ironman World Championships in Kona, Hawaii, where he and colleagues gave half of the athlete participants a probiotic supplement for four weeks prior to the race.
“When finalized, these data will help us to better understand, one, whether a probiotic supplement truly alters the gut microbiome of athletes, and two, whether a probiotic affects how the gut microbiome responds to exercise, and three, whether a probiotic may alleviate gastrointestinal distress and improve performance in athletes,” Grosicki said.
While the full results from these studies won’t be complete for some time.
Grosicki and Brown intend to return to the 2023 Western States Endurance Run in June to conduct another study, but this time they will focus more on the cardiovascular system of the athletes.
“We are hoping to learn how participating in ultra-endurance exercise affects blood vessel function, and the impact of these blood vessel alterations on the heart and kidneys,” Grosicki said.
The two were also recently awarded a grant to study the relationship between salt and fiber in the diet and vascular health.
“This grant will help tie in the interests that we have both in the gut microbiome and the cardiovascular system,” Brown added.
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