New study finds gut microbiome linked to how we cope with stress : Shots

A diagram of the human microbiome. Research has found that the bacteria in our gut may affect our mental health.

Mehau Kruk/Getty Images/Science Photo Library RF

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Mehau Kruk/Getty Images/Science Photo Library RF

The gut microbiome (our body's ecosystem of microorganisms) emerged. As a rich new field To study various psychiatric and neurological disorders.

Research demonstrates that the brain and gut are in constant communication and changes in the microbiome are linked to mood and mental health. Research published this month in Nature Mental Health Unique biological signatures have been found in the microbiomes of people who are highly resilient in the face of stressful events.

“The precision with which these patterns emerged was truly astonishing.” Alpana ChurchNeuroscientists at the Goodman Luskin Microbiome Center at the University of California, Los Angeles (UCLA) led the new study.

The study is a starting point for future human studies that some researchers believe could eventually lead to a cure or point the way to microbiome biomarkers that can help guide treatment and mental health decisions.

Recovery linked to anti-inflammatory microbes

For their analysis, Church and her team split 116 adults without diagnosed mental illness into two groups based on how they scored on a scale of psychological resilience.

Next, the team sifted through the massive amount of data they collected from brain imaging, stool samples, and psychological questionnaires, and fed it into a machine-learning model to find patterns.

Analysis of gene activity, metabolites and other data revealed several key associations in the high-resilience group: In the brain, there were increases in traits associated with emotional regulation and improved cognition.

“Think of the frontal part of the brain as a brake,” Church says. “People who are more resilient have very efficient brakes and are less likely to have an exaggerated stress response.”

The researchers then took a closer look at the microbiome, looking not only at the abundance of different microbes but also at their gene activity to find out what they were up to.

Two major patterns emerged in people who were more resilient to stress: microbiome activity was associated with reduced inflammation and improved intestinal barrier integrity.

the study Indicated Patients with various mental illnesses have been found to have a balanced gut microbiome, with higher concentrations of certain pro-inflammatory bacteria and lower concentrations of anti-inflammatory bacteria.

Church points out that the intestinal barrier absorbs nutrients and prevents toxins and pathogens from entering the bloodstream, and when the intestinal barrier becomes more permeable, or “leaky,” inflammation acts as a stress signal to the brain, telling it all isn't well.

Microbes that “talk” to our nervous system

The new study fits into a rapidly expanding body of research into the brain-gut connection.

“I was really excited to see this being done in a fairly large human cohort.” Thomas BastiaansenBioinformatician studying gut microbiome and mood at the Amsterdam University Medical Center.

In recent years, he says, scientists have established a strong “bidirectional relationship” between the gut and the brain, much of it based on preclinical studies using animal models and some human observational and in-vitro studies.

“All this points to roughly four ways in which the microbiome communicates with the host,” Bastiaanssen says.

Along with the immune system, the vagus nerve acts like a highway stretching from the brain to the gut, interacting directly with the microbiome.

These gut microbiota “talk” to the central nervous system by secreting neurotransmitters such as serotonin and dopamine (about 90% of serotonin and 50% of dopamine are produced in the gut).

Additionally, the microbiome can produce short-chain fatty acids that have a variety of benefits, including maintaining the integrity of the intestinal barrier and exerting anti-inflammatory effects on the brain.

Last year, Foster and her team found Depressed patients with elevated anxiety were found to have reduced bacterial communities involved in the production of these short-chain fatty acids.

In recent years, other observational studies have strengthened the evidence showing a link between the gut microbiota and human mental health.

For example, large-scale studies by researchers Netherlands A low bacterial diversity microbiome has been shown to be a predictor of depression. More or less The presence of certain bacteria involved in the synthesis of neurotransmitters and short-chain fatty acids may hold the key.

Foster praised the UCLA study as “novel” for its comprehensive look at the brain and gut microbiome and its potential role in resilience.

She noted that the analysis uncovered a link between anxiety and the microbiome, which is already well-known. field of studyMore than a decade ago, Foster and his colleagues demonstrated this link in experiments with “germ-free” mice and anxiety.

When it comes to stress, scientists have found that even short-term exposure to stress can lead to changes in the microbiome, and that altering the composition of the microbiome could improve stress resistance in some mice.

Probiotic Treatment for Stress? Not Yet

There are growing efforts to translate this research into practical treatments using diet and prebiotic and probiotic supplements, but Bastiaanssen says the complexity of the microbiome requires a different approach than that typically used in drug development, which tends to focus on finding single molecules or drugs.

It's like trying to grow a forest by planting a few seeds in the desert, he says.

“Obviously, that's not going to work,” he says, “because the ecosystem that supports it isn't there.”

He says the microbiome field is just getting out of its infancy.

“We've established the link between the microbiome and the gut-brain axis. The evidence is very solid,” he says. “The next question to understand is how it works.”

He points out that there is promising evidence from small human studies of targeting the microbiome with specific diets (in one case, Fermented foods are abundant) can reduce inflammation.

Another study by Bastiaansen and his team at University College Cork found that a diet focused on vegetables and foods known to influence the microbiome Perceived stress.

While these efforts are entirely “valid,” Foster argues that the power of these studies lies in the fact that they may lead to the discovery of biomarkers that can help guide decisions about how to use existing treatments and who might be the best candidates.

““Can we measure your microbiome, or maybe your blood, or something in your brain, to determine if you're depressed,” she says. “Should we give you an antidepressant… or neurostimulation therapy? Should we do cognitive behavioral therapy? Should we tell you to exercise?”

That could be the value of a comprehensive marker that can be measured in the microbiome, she says, and she thinks it could become an effective tool in clinical care within the next decade.

Church, on the other hand, thinks: Hypothetically, this area of ​​research could one day be used to develop probiotic blends that can “reduce stress” and prevent the onset of some diseases.

“The biggest problem is we need more studies that actually test these in human trials,” she says. She acknowledges that there are a lot of unsupported claims about improving the microbiome. For now, she tells people there's not enough data yet to know which treatments to try.

“There's nothing that's actually been tested,” she said. “Come back in a year or so, and I'll let you know.”