Endurance Athletes' Gut Microbiomes Defy Traditional Health Expectations
Dr. Frédéric Derbré shares insights on how endurance athletes' gut microbiomes differ from non-athletes.
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Elite endurance athletes are often seen as the archetype of health, with bodies finely tuned by rigorous training and optimal nutrition. So, it might come as a surprise that their gut microbiomes appear to be less diverse than those of the average person.
If a rich and varied gut microbiome is regarded as a sign of good health, why would some of the fittest people on the planet host microbial communities that seem to go against that grain?
Research on the gut microbiome has recently surged, with studies linking it to everything from mood regulation to metabolic disease. Exercise has also been shown to influence the composition and function of gut microbes, often with beneficial outcomes. But as scientists dig deeper, it’s becoming clear that the relationship between physical activity and the microbiome is far from straightforward.
To better understand this complexity, Technology Networks spoke with Dr. Frédéric Derbré, an assistant professor at the Rennes 2 University. Derbré recently published a study in Cell Reports, which investigated how the gut microbiota of elite endurance athletes – such as professional cyclists – differs from that of their non-athletic peers.
The study’s findings challenge assumptions and add nuance to our understanding of what a “fit” microbiome might look like. By rigorously controlling for dietary variables, the team was able to isolate the effect of exercise capacity itself. They then used fecal microbiota transplantation (FMT) in mice to explore how these athlete-associated microbes might influence host metabolism.
Fecal microbiota transplantation
FMT is a procedure where gut bacteria from a healthy donor’s stool are introduced into the gastrointestinal tract of a recipient, typically to restore a balanced microbial community or study the effects of specific microbiota compositions.
In our Q&A with Derbré, we explore the surprising features of the athletic gut microbiome, how these microbes might offer metabolic advantages and what the findings could mean for both clinical applications and our evolving definition of microbial health.
What distinguishes the microbial ecosystem of endurance athletes from that of the general population?
Frédéric Derbré, PhD (FD):
In our study, the gut bacterial ecosystem of athletes with high aerobic exercise capacity (mostly elite cyclists) was found to be less diverse, with lower bacterial density and reduced functionality.
Surprisingly, this microbiota still appeared to produce a high amount of short-chain fatty acids, suggesting a potential specialization of the ecosystem toward the production of these metabolites involved in energy metabolism. This is the hypothesis we propose based on our recently published findings.
RLS:
FD:
Some bacterial species were found to be highly abundant in the gut ecosystem of endurance athletes, notably Prevotella copri. However, this does not necessarily imply that this dominant species is directly involved in their performance.
It may, in fact, be the tree that hides the forest, overshadowing less abundant bacterial communities that could be equally, if not more, impactful.
Indeed, Prevotella copri did not successfully engraft in the transplanted mice, despite the notable metabolic effects we observed in these animals.
RLS:
FD:
When this ecosystem is transplanted into mice, we saw that metabolic benefits were induced, most notably an improvement in insulin sensitivity.
However, fecal transplantation alone did not lead to enhanced physical performance in the mice, suggesting that a host-derived pressure or physiological stress may be necessary to reveal the full potential of this microbiota. It is possible that our results would have differed had the transplantation been combined with an exercise training protocol in the mice.
RLS:
FD:
Possibly. However, it’s also possible that this specialization of the gut microbiota in endurance-trained athletes could be a double-edged sword.
The reduced microbial diversity might actually make the ecosystem more vulnerable, potentially facilitating the implantation of pathogenic bacteria.
We're only at the beginning of our investigations into this fascinating question.
RLS:
FD:
We first recruited elite athletes, mainly cyclists and football players. These athletes filled out a detailed questionnaire about their dietary habits. We then launched a recruitment campaign to find non-athletic individuals who were of normal weight and in the same age range as the athletes.
To make sure that any differences observed wouldn’t simply be due to diet, each candidate was also asked to complete the same dietary questionnaire.
Using a selection algorithm, we identified only those whose diet was qualitatively similar to that of the athletes. Out of more than 100 volunteers, only 20 were selected.
This process turned out to be quite challenging, as it's rare to find people who eat healthily and maintain a normal weight, but engage in little or no physical activity.
RLS:
FD:
