Many of us know the sensation of getting “butterflies” in our stomachs when we’re nervous, but we might not realize just how connected our gut and our mental health are.
A study from UCLA Health published this month in the Nature journal provides new insight into how the brain-gut microbiome (BGM) system influences mental health. Findings from the study suggest that the microbiome is “critical in shaping resilience.”
This brain-gut microbiome is part of what researchers described as “an ecosystem consisting of trillions of microorganisms residing in and on the human body,” and they said it functions as a “bidirectional signaling mechanism between the central nervous system (CNS) and gastrointestinal tract.”
Researchers also explained that gut microbiota produces hormones, neurotransmitters such as serotonin related to psychological stress – in fact up to 95% of serotonin is produced in the gut. Main metabolites produced by gut microbiota are short-chain fatty acids. These are known to influence cognitive and emotional processing through anti-inflammatory effects on the brain.
“When most people think about mental health, they only think about the brain, but there is bi-directional communication between the gut and brain,” Arpana Gupta, PhD, co-director of the Goodman-Luskin Microbiome Center at UCLA and senior author of the study, previously said. “I tell people the gut and the brain are like BFFs. The brain and the gut are in constant communication with each other.”
Gupta and her team studied a cohort of 116 healthy individuals, including 71 women, who were recruited from the Los Angeles community through advertisements for the study. They characterized brain-gut microbiome patterns related to resilience by analyzing fecal samples and multimodal magnetic resonance imaging. Participants were separated into “high resilience” and “low resilience” groups, based on depression and anxiety symptoms.
“High-resilience phenotype was associated with lower depression and anxiety symptoms, higher frequency of bacterial transcriptomes….
increased metabolites… and cortical signatures,” said the study. This indicates that “microbiome modifications can optimize mental health.”
Researchers said that more than $300 billion is lost annually due to stress-related healthcare costs and missed work in the U.S., which alone highlights a need for more strategies for improving mental health. Results from the National Center for Health Statistics and U.S. Census Bureau Household Pulse Survey found that in 2019, 8.1% of adults aged 18 and over had symptoms of anxiety disorder, 6.5% had symptoms of depressive disorder, and 10.8% had symptoms of anxiety disorder or depressive disorder.
Developing resilience to stress may help those struggling with mental health challenges, which can lead to maladaptive coping mechanisms such as alcohol misuse. High-resilience individuals are also more likely to have traits like mindfulness, to be nonjudgmental and to express empathy.
“Definitions of resilience generally refer to beneficial outcomes in response to threat or stressful events,” said the study. “Resilience involves positive acceptance of change, tolerance of negative affect, tenacity and the ability to recover after stressful events. “
According to UCLA, “the high resiliency group’s microbiomes excreted metabolites and exhibited gene activity associated with low inflammation and a strong and healthy gut barrier,” opposed to a “leaky gut” caused by inflammation. When a person has a leaky gut, their gut barrier’s ability to absorb essential nutrients and block toxins is impaired.
“Our findings suggest resilient individuals, particularly those demonstrating tenacity and perceived ability to control life outcomes, possess a microbiome that supports gut-barrier integrity and eubiosis [healthy gut balance] and a cortical signature that reflects adaptive emotional and cognitive regulation,” said the study authors.
What does all this mean? Well, researchers believe that the clinical implications could indicate fecal transplantation – a procedure where healthy bacteria (microbiota) from the feces of a carefully screened donor and transferring them to the colon of the recipient, per Johns Hopkins – could improve resilience to stress. Going forward, the UCLA team’s future research will focus on interventions.
“If we can identify what a healthy resilient brain and microbiome look like, then we can develop targeted interventions to those areas to reduce stress,” said Gupta. “This is believed to be the first study to explore the intersection of resiliency, the brain, and the gut microbiome.”
Additionally, the study indicates dietary modifications may improve mental health. Avoiding processed foods may be beneficial, but not if doing so causes stress, said Gupta.
Natalie Gavi, RD, a registered dietitian with the UCLA Steve Tisch BrainSPORT Program, previously recommended some probiotic foods to help improve the brain-gut interaction. They include: yogurt, sauerkraut, kefir, miso, tempeh, kombucha and kimchi. She stressed that these foods should be as fresh as possible for the maximum benefit. Gavi also recommended several prebiotic foods, including: asparagus, apples, Jerusalem artichokes, bananas, oats, onions, garlic and leek.