Delphine Schiltz
modified to
2:57 p.m., January 10, 2023
You are certainly familiar with dopamine. It is the hormone of happiness, responsible for the notion of pleasure in our brain. What you may not know is that the intestinal flora would make it possible to produce it and find motivation… to play sports. In any case, this was shown by an Israeli team from the University of Pennsylvania, in recent experiments carried out on mice. So how does it work ? Elements of explanation with Philippe Gérard, research director at INRA Jouy-en-Josas and specialist in the role of the intestinal microbiota on health.
What is this study?
In this study conducted by an Israeli team, the researchers looked at the potential role of the intestinal microbiota in the motivation to exercise. For this, they used a cohort of 200 mice, from 8 different genetic backgrounds. And they made them exercise, either on a treadmill or in a wheel.
They were able to show that all the mice did not have the same motivation to exercise: some ran longer. To understand these differences in sports performance, the researchers analyzed a whole bunch of parameters, and to their surprise, they discovered that it was the intestinal flora that best explained why some mice ran longer than others.
To then verify this hypothesis, they destroyed the intestinal flora of the mice by giving them antibiotics. Then, they reintroduced certain bacteria into the intestines of the mice to test them. Thanks to this process, the researchers observed that this new intestinal flora was able to improve the sports performance of the mice, to make them run longer.
How can we explain this phenomenon?
In fact, the researchers found that these “special” bacteria had all the same particularity: that of synthesizing molecules in the intestine, called fatty acid amides, at the origin of a chain reaction. The fatty acid amides produced by the bacteria in the flora activate neurons present in the intestine, which themselves activate neurons in the spinal cord, which will stimulate the production of dopamine in the brain. These bacteria kind of cause a motivational shot.
What are the limits and potential applications of this study?
To begin with, one cannot completely extrapolate from results obtained in mice. We must verify that in humans, we also have these bacterial species that are capable of increasing dopamine. I think that’s typically what this Israeli team is checking. For applications, I think there are many. We know very well that the practice of sport is beneficial for health and that one of the main brakes is that people don’t want to.
If we found bacteria that we could implant in their intestines to make them want to, of course, that would be a big step forward. We are not there at all, but if that is what we can imagine in any case, when we read the results obtained in this article. Now it was thought that genetic factors determined motivation for sport.