The main lifestyle difference the researchers were interested in was the fact that these monks meditated for over two hours a day. They wondered if meditation might have an impact on the microbiome (which is the types and amounts of bacteria found in the gut, as analyzed from a person’s stool).
The resulting study, published in the British Medical Journal’s General Psychiatry, found that the monks had higher quantities of certain bacteria that are associated with lower levels of depression, anxiety, and cardiovascular disease. The exciting findings caught the attention of outlets like The Guardian, Healthline, and others. So, does the study show that meditation is good for the gut, and subsequently good for your overall health?
Unfortunately, it’s not so clear cut.
“I’m not sure how much I would really take home from that study,” Emeran Mayer, MD, a gastroenterologist, UCLA medical school professor, Seed Health board member, and the author of the book The Mind-Gut Connection, says. “There’s more limitations than positives.”
Dr. Mayer says the technical methods the researchers used to analyze the samples were outdated. The study size as a whole was small, and the control group (just 19 people) was not robust enough to draw conclusions of difference from. He's skeptical that samples could maintain their integrity even in a refrigerated box for a trip down a mountain and on a plane; most studies, he says, require very controlled sample collection that happens in a lab. And he also points out that diet and the sedentary lifestyle of monks was not taken into account.
Speaking with Prevention, Martin J. Blaser, MD, professor and Henry Rutgers chair of the human microbiome at Rutgers Robert Wood Johnson Medical School, thought the study was “well conducted,” but didn’t think meditation could be pinpointed as the defining factor that accounted for potential differences in the microbiomes of the monks versus the control group.
So, essentially, even if the findings sound exciting, experts aren’t confident that this is the study for meditation x gut health enthusiasts to hang their hats on.
What’s the big deal with "gut health" anyway?
“Gut health” has been an exciting concept (and buzzword) for years, with proponents claiming that the population of diverse, robust bacteria inside of us can influence everything from chronic disease to mental health. Our stomachs produce a lot of the substances we need to fight disease, manage inflammation, and regulate our mood (for example, most of the body’s serotonin comes from the gut). So the “mind-gut axis” is an exploding field for research.
“It turns out that microorganisms can actually counteract the harmful effects of food, drugs, hormones in our bodies, either introduced from the outside or produced inside our bodies," Ian Smith, MD, best-selling author and chief medical advisor for the probiotics brand Jetson, previously told Well+Good. "The sheer number of conditions that have been found to link back to gut health is in itself an exciting advancement: things like obesity, diabetes, liver diseases, cancer, and even neurodegenerative diseases."
Still, some researchers caution that many of the claims are overblown, and Dr. Mayer gives the caveat that “the majority of really revolutionary findings in the brain-gut microbiome space has come from animal models,” which he says can’t necessarily be extrapolated to humans. Furthermore, what constitutes a “healthy gut” isn’t so clearly defined, and could vary from person to person.
“We don’t know what a ‘normal’ microbiome looks like," Ali Rezaie, MD, a gastroenterologist and co-author of The Microbiome Connection, previously told Well+Good. "Your microbiome is unique to you, and there’s no known magic mix of bacteria."
Okay, but could meditation positively impact your gut microbiome?
Dr. Mayer’s skepticism for the Tibetan monk study in particular does not mean he thinks the theory itself doesn’t hold water. A long-time meditation practitioner (Dr. Mayer and his wife even got married at a Tibetan monastery in Kathmandu), and an expert in studying the connection between the gut, body, and brain, Dr. Mayer says it makes sense that meditation could impact the microbiome in a positive way. That’s all down to the growing (but still not-definitive) body of research showing that meditation can possibly reduce stress, and evidence is amassing that stress can wreak havoc on the gut.
When we’re stressed, our sympathetic nervous system gets activated. That activation “changes the environment in which the microbes live, their habitat,” Dr. Mayer says, including blood flow, contractions, mucus production, and more. Certain neurotransmitters, like norepinephrine, can make their way into the gut, which “modifies gene expression of the microbes," he says. A meta-analysis of studies found that more research is needed to further understand how stress affects the gut (much of the research has been done on mice), “but emerging human evidence has begun to corroborate preclinical findings” that stress can impact gut health.
“If relaxation and stress reduction and meditation decrease sympathetic nervous system tone and reactivity, then I think that will be the most possible explanation for changes in microbiome,” Dr. Mayer says.
Other studies have shown some promise for this hypothesis. One small study that looked at meditation practitioners who ate a vegan diet found a higher prevalence of beneficial bacteria versus a control group. A meta-analysis of studies that looked at topics including stress, the microbiome, epigenetics, and meditation concluded that “during stress, an altered gut microbial population affects the regulation of neurotransmitters mediated by the microbiome and gut barrier function. Meditation helps regulate the stress response, thereby suppressing chronic inflammation states and maintaining a healthy gut-barrier function.” While other papers suggest that these statements are not so clearly established as scientific fact, the stress-gut connection—and meditation’s ability to modulate it—are not so theoretically far-fetched.
So should you be making like a Buddhist monk and meditating for two hours every day for the sake of your microbiome? There’s probably no need to divest of all your worldly belongings just yet—but don’t ignore the potential power of a meditation practice to contribute to your overall health and wellbeing (and subsequently, your gut).
“The ultimate thing is really to have a microbiome-friendly diet, plus the contemplative component, you know, the half hour meditation,” Dr. Mayer says. “A healthy lifestyle should have both.”
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