Each month, it seems, we discover a new reason to appreciate the billions of bugs hanging out in our bellies. Why? They are far more influential than we ever thought.
As our colleague Rob Stein reported in his Guts and Glory series, the bacteria in our gastrointestinal tracts and on our skin may be doing everything from guiding the workings of our minds to helping us either fend off or become more predisposed to certain diseases.
And, as Michaeleen Doucleff has explained, a mix of microbes in our gut may even help us reap the benefits of the health-promoting polyphenols in chocolate. How wonderful!
Now a study, published online in the journal Gut, suggests exercise may give our microbiomes a boost — especially in supporting a rich, diverse mix of different bacteria.
Researchers at the University College of Cork studied a group of 40 rugby players as they trained for the season at a training camp.
"We picked professional athletes because ... we could track the levels of exercise and literally observe what they eat," Fergus Shanahan, a gastroenterologist who authored the study, tells The Salt. And by taking stool samples, Shanahan and his colleagues could examine changes in the players' gut bacteria
The researchers then compared the rugby players with another group of healthy men who were not professional athletes but had similar weights and ages.
And they found significant differences.
"[The rugby players] had a very diverse or a broader range of microbes in their GI tracts compared to the healthy controls," explains Shanahan. "And [the rugby players] also had higher levels of certain bacteria that we generally associate with good health."
Take, for instance, a bacterium called Akkermansiaceae. Shanahan says the mechanism of how this bacterium influences health isn't clear, but low or decreasing levels of it are linked to bowel and metabolic disorders. Whereas, he says, "high levels are generally associated with good health."
The other significant difference between the rugby players and the healthy control group was the level of protein in their diets. The rugby players consumed about 22 percent of their calories from protein, compared to 15 percent among the men in the control group.
Now, a lot of studies have already shown that diet influences the collection of gut microbes. We also know that if you exercise a lot, your diet will likely change.
So the question is, how might diet and exercise be working together to create a diverse community of gut bacteria? The researchers aren't sure, but theirs is the first real study to even try to understand that.
Researcher Georgina Hold of the University of Aberdeen has long studied the role of microorganisms in gastrointestinal disease. She tells us that this paper is more evidence that "it's a combination of what you eat — and how healthy your lifestyle is — contributing to the health of the gut microbiota."
But she says it's important not to focus on the influence of any single bacterium. "This is all about a collection of bacteria that live in the gut," says Hold, not about one in isolation.
She explains that different types of bacteria have different functions. For instance, some gut bacteria are good at detoxifying the nasty compounds we ingest. Other bacteria actually help break down the fiber in the food we eat — and may generate some gas while they're at it.
"It's a combination of bacteria that — in the right proportions, doing their own unique functions — will actually have a huge impact on the health of our gut," Hold says.