Athlete Poop Won't Improve Your Athletic Performance

By Ryan F. Mandelbaum on at

The human body isn’t just your cells, but a home for trillions of bacteria. We know that many of those bacteria serve important purposes, and imbalances or a lack of diversity could lead to illness. But research into this field is pretty new. At least, new enough that you shouldn’t just transplant someone else’s gut bacteria into your own colon without good reason.

Recently, The Scientist reported that Lauren Petersen from the Jackson Laboratory for Genomic Medicine in Connecticut is working on a study surveying athletes’ gut bacteria. But in the article, she also discusses how she received a fecal transplant and, afterwards, performed better athletically after dealing with a long bout of illness. She stated this might be something that athletes can do to boost their performance in the future. As she told Bicycling magazine, “I think I can say with confidence that bacterial doping — call it poop doping, if you must — is coming soon.”

Fecal transplants are a thing. When antibiotics don’t work for Clostridium difficile infections, scientists might treat it with a literal poop transplant — putting a healthy patient’s poop, containing a sampling of their gut bacteria, into the sick patient’s colon so the healthy bacteria can colonise it.

That’s the only currently approved use of fecal transplants. Scientists are definitely studying the microbiome, the zoo of different bacteria in your body, and finding promising results in terms of how it relates to things like colitis or even autism. But science is nowhere near ready to fecal transplants as supplements, let alone as athletic performance enhancers.

“A bunch of elite cyclists have a microbiome that looks like this,” the way Petersen describes, fecal transplant expert and professor Elizabeth Hohmann from Massachusetts General Hospital told Gizmodo. “So what? Is that because of the foods they eat?” After all, it could be the lifestyle that makes their microbiome look the way it does, not the microbiome that makes them better performers. “There are associations, but not causal. The idea that [microorganisms like] Methanobrevibacter smithii or Prevotella will make you a better performer is ridiculous.”

The bacteria reported at higher levels in the cyclists by Peterson are also elevated in a “bewildering array of different populations including in my own cohorts of HIV positive individuals (but associate with sexual behaviour; men who have sex with men, and not HIV itself), rheumatoid arthritis, some morbidly obese people, people who eat certain high-fiber type diets, etc.,” Catherine Lozupone, microbiologist at the University of Colorado, Denver told Gizmodo in an email. She reminded me that the cyclist study was real and reputable, but said that “we really do not understand very well what the hell Prevotella is doing in the gut…”

And the fact that Petersen felt better after a fecal transplant is an anecdote that could simply be the placebo effect in action.

There’s always the chance that poop doping could be harmful, too. “There’s the risk of transmission of infections agents for sure,” Hohmann said. Salmonella can stick around in the adult gut for several weeks, for example. Someone who might not even remember a bad bout of diarrhoea weeks before could potentially pass along this pathogen in a fecal transplant.

“Until there’s peer reviewed literature it’s irresponsible,” to recommend poop doping, Bryan White, Director of Microbiome Projects in the Division of Nutritional Sciences at the University of Illinois told Gizmodo. “Will athletes do it? If they think they can get something out of it they’ll do it. That’s why it’s irresponsible.”

Microbiome research is incredible, and there are so many potential things to be discovered about our gut bacteria. But scientists are not sure what role all the specific bacteria have yet.

And science is certainly not ready to recommend putting someone else’s poop in your butt.