In a previous post about intestinal microbes and athletic performance we told you that a number of things like diet and type of exercise can impact the microbes found in your intestinal tract. Usually by increasing the diversity of microbes living in the gut. We also explained that this acts as a positive feedback loop because the microbes in your intestine can then directly influence your performance during exercise. For example, microbes in the intestinal tract of someone who works out produce more short chain fatty acids (SCFAs) which have a huge number of benefits to health. If you missed the last article you can read about it here.
To further illustrate the link between the gut microbiome and diet/exercise, we wanted to take a closer look at examples of 2 types of professional athletes and how their intestinal microbiota compared to average people’s.
Marathon runners—Scheiman et al. 2019 In this study, researchers collected samples from individuals who had just finished running a marathon and found that a specific type of bacteria was present in higher concentrations after the marathon was completed. This bacterium, Veillonella atypica, was then isolated and put into the intestinal tract of laboratory mice to see if researchers could observe any differences in the performance of mice with V. atypica and mice without.
To test for these differences, the scientists observed mice running on a treadmill and found that the mice with V. atypica could run on the treadmill for longer without getting exhausted than the mice without the marathon-running bacteria.
In the intestinal tract this type of bacteria is known to break down lactate. Therefore, to get a more global view of lactate utilizing bacteria in elite athletes, the authors of this research looked at the number of lactate-metabolizing genes in fecal samples. They found that elite athletes have a higher number of lactate-utilizing genes post exercise - suggesting that there are more bacteria present after exercising that are using lactate.
When bacteria like V. atypica break down lactate, they produce a SCFA called propionate, which as we discussed in the last post, is known to be extremely beneficial for the human body - specifically the skin cells in the intestinal tract. The researchers here also found that by giving mice propionate, they could increase run time on the treadmills as well.
These results taken together led them to the conclusion that the microbial breakdown of lactate to propionate can directly benefit athletes. This is important because this study provides a concrete example of how microbes can positively influence athletic performance.
To test for these differences, the scientists observed mice running on a treadmill and found that the mice with V. atypica could run on the treadmill for longer without getting exhausted than the mice without the "marathon-running" bacteria.
Competitive Cyclists—Petersen et al. 2017
Another study looked at cyclists and what kind of microbes they host in their intestine. The researchers found that the 33 individuals they collect samples from could largely be placed into 3 categories determined by the abundance of specific types of bacteria. More specifically:
High in Prevotella
High in Bacteroides
A mix of the two
The amount of time spent biking every week was determined to be linked to the high abundance of the genus Prevotella, and a microbe that can make methane gas called Methanobrevibacter smithii (an organism evolutionarily distinct from bacteria, called archaea) was identified as being more active in professional cyclists compared to the amateurs.
Previous research has linked Prevotella to the consumption of carbohydrates (Wu et al., 2011), and the authors suggest that the cyclists who spend more time exercising during the week likely consume more carbohydrates which has resulted in the abundance of these bacteria in their intestinal tract. When they ran analyses to link this bacterium to different metabolic pathways in the intestinal tract, they were able to determine that Prevotella is significantly correlated to a variety of metabolisms including that of carbohydrates.
Because the metabolism of the methanogen, M. smithii, was upregulated in professional cyclists, the researchers hypothesized that this microbe might play a role in increasing the efficiency of the consumption of carbohydrates by bacteria like Prevotella.
Conclusions
The goal of this post is to highlight the complexities of the intestinal microbiome. While it’s clear that diet and exercise impact which microbes live in your gut, there are no set ‘rules’ about how your microbial community will respond to changes in your lifestyle.
Marathon runners were shown to have an increase in a very specific species of bacteria, which when put into mice helped the mice run on tiny little mice treadmills for a longer time. To-date this is the only study to have shown these types of compelling results (that we’re aware of). So of course, further research is needed to understand exactly how V. atypica could be incorporated into your intestinal microbiome to increase your weekly running distances.
Cyclists had more subtle differences that are likely linked to their consumption of carbohydrates, which is believed to support an abundant community of Prevotella bacteria. The results also indicated that Prevotella might be so successful in carbo-loaded intestinal tracts because of the activity of the methanogen, Methanobrevibacter smithii.
References:
Scheiman J, Luber JM, Chavkin TA, et al. Meta-omics analysis of elite athletes identifies a performance-enhancing microbe that functions via lactate metabolism. Nat Med. 2019. doi:10.1038/s41591-019-0485-4
Petersen, L.M., Bautista, E.J., Nguyen, H. et al. Community characteristics of the gut microbiomes of competitive cyclists. Microbiome. 2017. doi:10.1186/s40168-017-0320-4
Wu GD, Chen J, Hoffmann C, Bittinger K, Chen Y, Keilbaugh SA, et al. Linking long-term dietary patterns with gut microbial enterotypes. Science. 2011.
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