Gut Check

Can the bacteria in your gut make you a faster cyclist, boost your endurance as an ultrarunner or improve your rugby game?

Everybody poops. Sure, we don’t like to talk about it (at least amongst more refined company), but it’s a fact of life. Most people write it off as a necessary bodily function that need not be discussed nor given much thought.

Not so for Lauren Petersen, Ph.D.,  genomicist who lives in the Upper Valley. Though she’s no longer racing,  Vermonters may know Petersen as a former blazingly-fast mountain bike pro who has held a  podium spot in events such as the Clif Enduro East and Vittoria Cup.

But in scientific circles, Petersen is better known as the founder of the Athlete Microbiome Project and a genomicist who did some pioneering  studies on the gut microbiology of athletes.

After being diagnosed with Lyme Disease at age 11, Petersen tried nearly all the available medical options to address her debilitating symptoms. Multiple courses of broad spectrum antibiotics were finally effective and at age 21, she was cured. But she still suffered from chronic fatigue. The antibiotics had attacked many of the beneficial bacteria in her gut, leaving her with digestive issues and constantly tired. With little hope of improving her symptoms through conventional treatments, Petersen, then 31, offered herself up as a guinea pig in 2014 for a largely untested procedure; a fecal transplant.

The results of her last-resort treatment were remarkable. Within two months of the procedure, Petersen began feeling better. And soon the former downhiller began racing mountain bikes again, this time, in enduro events. It just so happens that the fecal transplant Petersen received was from a competitive cyclist and her interest was piqued. Petersen conducted a pilot study, testing the gut microbiomes of 22 professional and 11 amateur competitive cyclists. Analysis revealed the cyclists with the highest training volume had a higher abundance of a specific strain of bacteria. This begged the question; could we create better athletes by altering their gut microbiome?

The Scoop on Poop

To understand why in the world anyone would ever agree to a fecal transplant we must first grasp what the gut microbiome is and how it relates to the aforementioned four letter word: poop.

Our gut microbiome consists of over 1,000 different species of bacteria that can (en masse) weigh in at around four pounds. About one-third of the microorganisms in our gut are common to most people, while the other two-thirds are unique to each individual.

The bacteria in our gut play a role in digestion and absorption, immune health, body weight, disease risk and mental health among other things. The composition of our gut microbiome is determined by genetics, diet, lifestyle and medications. By testing fecal samples (fancy wording for poop), researchers can determine the individual strains of bacteria that populate an individual’s gut. So what does our gut microbiome say about our athletic ability?

Researchers posit that the composition of an athlete’s gut microbiome is different from that of a sedentary individual and evidence from fecal testing supports this.

As part of her work with the Athlete Microbiome Project, Petersen, then at Jackson Laboratory for Genomic Medicine in Farmington, Ct., found that all the top-level cyclists tested had specific microorganisms whereas non-athletes rarely harbored these particular strains.  The question then becomes which came first, the chicken or the egg. Does high-level training induce changes in our gut microbiome or does the right mix of microorganisms predispose some to outperform others? Unfortunately, we don’t yet have the answer to this and due to the complex nature of the gut microbiome it will be extremely difficult to determine.

Regardless, there is no question that our gut microbiome plays a role in our athletic ability. It makes sense. Our body needs to convert the food we eat into fuel to power activity and the ability to do so is dependent on our gut function.

Bad-Ass Bacteria

Although a relatively new area of study, Petersen’s pilot study is not the only one out there.

A team of Harvard researchers have been studying the gut microbiome of athletes from a number of different sports including marathoners. In 2015, they tested the fecal samples of 20 athletes participating in the Boston Marathon. By testing samples from 20 runner one week prior to and one week after the race they found that after completing a marathon the population of certain strain of bacteria spiked.

The microorganism in question works to break down lactic acid, a byproduct of intense exercise that can promote fatigue and muscle soreness. By having more of these microbes available to breakdown the buildup of lactic acid, athletes would theoretically be able to push themselves harder.

One of the Harvard researchers, Jonathan Scheiman, Ph.D. noted when he presented his research: “The bugs in our gut affect our energy metabolism, making it easier to break down carbohydrates, protein and fiber. They are also involved in inflammation and neurological function. So perhaps the microbiome could be relevant for applications in endurance, recovery and maybe even mental toughness.”

In another study of ultrarunners and Olympic rowers, researchers were able to identify a higher prevalence of bacteria that helps metabolize fiber and complex carbohydrates in ultramarathoners as compared with the rowers. Although both groups would be considered high level athletes, ultrarunning demands longer exertion. Having a gut microbiome that is more efficient at extracting energy from food certainly would boost performance among those competing at such long distances.

And in 2016, researchers in Cork, Ireland examined the bacteria in fecal samples from 40 professional rugby players compared to 43 sedentary individuals. The rugby players were found to have distinct differences in the composition of their gut microbiome and overall had much greater variety of species populating their gut.

Not all professional athletes have the same level of fitness so to generalize that a rugby player’s microbiome would reflect that of a different type of athlete is a stretch.

To address this issue another study stratified 39 research subjects based on their fitness level. By measuring subjects’ VO2max, the maximum amount of oxygen used, researchers found that those in better shape also had more diverse gut microbiomes.

Gut Checks?

But the question remains: did ultramarathoners, for instance, experience a change in their gut microbiome as a result of their training or were they simply drawn to such a sport because their gut microbiome allowed them to excel?

Despite the uncertainty, some athletes looking for an extra edge are eager to harness the potential of microorganisms to take their performance to the next level. In the future, that could lead some to opt for elective fecal transplants from a high-level athlete “donor.”

Before you share on Facebook your intentions of getting a fecal transplant, know it isn’t as simple as calling up your physician for an appointment.

In 2013, the FDA classified fecal transplants as an Investigational New Drug. This means that at present individuals in the United States can only pursue such transplants as a treatment for Clostridium Difficile (C Diff). It remains to be seen if the use of fecal transplants will be approved for additional medical conditions let alone as an elective procedure.

Fecal transplants might sound like the type of science dreamed up in Dr. Frankenstein’s laboratory and certainly as stomach churning (pun intended). However, the potential to improve not only our health, but also athletic performance is a real possibility. Who knows, maybe we will wind up seeing professional athletes auctioning off their “specimens” to the highest bidder.

One of the goals of researchers is to be able to replicate the effects of the bacteria with a supplement. Just as many people take a probiotic supplement to improve their digestive and immune health, there may one day be the opportunity to purchase probiotics specific to athletic performance.

But being able to do so will undoubtedly bring with it the inevitable issues of appropriate use, dosage and even legality.

Could a microorganism be likened to steroids or other banned substances? If science does end up backing up the hype, will the acquisition of these super strains of bacteria be contained in a supplement (so as to avoid the cringe-inducing fecal transplant.)

Although these studies are illuminating, the issue still remains; does exercise lead to more diverse gut microbiomes or do those who have more diversity naturally end up being more athletically inclined?

But that is not the only issue. Another confounding variable is diet. One could argue that fitter individuals tend to have healthier diets and thus have a healthier gut microbiome.

For now, answers are few as we await more research to determine if probiotics are the key to athletic success or if it’s all just a load of crap.

Sorry I couldn’t help but squeeze in one last pun.

4 Ways to Build a Better Microbiome

Whether probiotics are the next big performance enhancing supplement or not, there is no question a healthy gut microbiome is important for our overall wellbeing.  What can you do (short of a fecal transplant) to improve your gut flora? Here are some easy answers.

Load Up Good Bacteria

The number one thing you can do to establish a healthy population of bacteria in your gut is to simply eat said healthy bacteria. Fermented foods are rich in a range of probiotics and can easily be incorporated into your diet. Yogurt, kefir, kombucha, kim-chi, miso and sauerkraut all contain a range of bacteria species that have been shown to improve digestive and immune health.

Feed Your Gut

Once you have good bacteria in your system, the next thing you must do is feed them. That’s right,  bacteria, just like any other living thing, need food to survive. Probiotics thrive on what is referred to as prebiotics. Prebiotic foods are those high in a particular type of fiber that probiotics feed off of. Foods rich in prebiotics include dandelion greens, garlic, onions, asparagus, bananas, oats, barley and flax seeds, among others. 

Keep the Bad Stuff at Bay

Creating a healthy gut microbiome is not only about eating the right things, it also entails avoiding things that can fuel the growth of bad bacteria. I like to think of the gut microbiome as a battleground of sorts. There are good and bad bacteria constantly fighting for resources and which type wins out greatly affects your health. Keeping harmful bacteria at bay is just as important as taking in probiotic-rich foods and fueling those good-for-you bacteria. Bad bacteria in our gut thrive on sugar and refined grains. But before you jump on the artificial sweetener bandwagon, know that studies have shown that artificial sweeteners can negatively affect the gut microbiota as well. Simply restricting your intake of sugar and refined grains — without the artificial substitutes — can essentially starve out the bad bacteria in our gut, creating a healthier gut microbiome where probiotics rule the roost.

Beware of Antibiotics

One other thing that can seriously throw off our gut health is something we typically take to improve our health; antibiotics. Antibiotics are routinely prescribed to kill bacteria that cause illness or infections. Unfortunately, antibiotics can kill off not only their intended target, but also the probiotics in our gut. In this case, the medicine we use to resolve one health concern may just lead to another. When it is necessary to take antibiotics be sure to incorporate probiotic- and prebiotic-rich foods in your diet to reinoculate your gut. That can help ensure you keep your health and gut in check.

As the Director of Nutrition at The Edge in Burlington, Jamie Sheahan works closely with athletes to develop customized fueling plans to optimize their health and performance. She is also an adjunct professor of sports nutrition at UVM. An avid runner, Jamie has completed more than 20 marathons.

Featured Photo by Jeb Wallace-Brodeur. 


Updated, 9-11-2018: Eds note: The original version contained several errors due to editing and has been updated to reflect the fact that Lauren Petersen is no longer working on the Athlete Microbiome Project and has retired from mountain bike racing. She was cured of Lyme Disease at age 21 and had the fecal transplant at age 31. We regret the errors.