The gut is often called the body’s second brain because it contains a vast network of neurons—around 100 million—in what’s called the enteric nervous system. This system can operate independently of the brain and, of course, plays a key role in controlling digestion.
Many people don’t realize that the gut also produces neurotransmitters, such as serotonin, which are important for regulating mood and emotions. In fact, contrary to common perception, 90 percent of the body’s serotonin is produced in the gut.
We’ve known for some time that the gut-brain connection—the complex communication network between the gut and the brain—is crucial for overall health, influencing digestion, emotions, mood, and cognitive functions.
Research has shown that the gut and brain communicate through the vagus nerve, the bloodstream, and the immune system, affecting everything from the stress response to mental health conditions like anxiety and depression to physical health.
Scientists also talk about the brain-gut microbiome system, the close relationship between your brain, your gut, and the trillions of tiny bacteria living in your gut, known as the microbiome. These systems communicate with each other all the time in a bidirectional way, which means that the brain influences gut health and the gut can impact brain function. The brain and gut microbiome go hand in hand: If one is out of whack, the other will soon follow.
Stress is a part of life that can rear its head at any age, from the infant left to cry in their crib to the youngster adrift at school, from the adult overworked at the office to the senior facing the death of a spouse.
Stress’s tentacles are wide-reaching: 77 percent of Americans report physical symptoms caused by stress, and 33 percent of Americans report that they are living with extreme stress. Stress is not limited to the development of mental health issues like depression. It has also been linked to the onset and the progression of diseases such as cardiovascular disease and diabetes and a wide panoply of health issues like obesity and irritable bowel syndrome—in fact, its impact is equal to smoking five cigarettes a day. This all accounts for over $300 billion lost annually from missed work and stress-related health-care costs.
How does stress snowball? When you’re stressed, your brain sends signals to your gut that can upset the balance of your gut bacteria, leading to digestive issues like stomachaches or changes in your bowel movements. Also, your gut bacteria send signals back to your brain, which can make you feel more anxious or stressed, creating a loop of distress that can lead to chronic inflammation, weakening your immune system and increasing your risk of long-term illnesses.
The depth of the gut-brain connection is why it’s so important to manage stress in order to maintain a healthy balance in your gut, which in turn supports your overall physical and mental well-being.
Researchers have traditionally focused their energy on investigating disease, treating disease, and understanding how stress leads to disease. “But my team and I wanted to see what could be learned if we flipped the switch and looked at the other side of the coin by studying individuals who, despite experiencing stress, do well and do not develop disease,” Arpana “Annie” Church, PhD, an assistant professor at UCLA, told Bottom Line Health. “I strongly believe that by pursuing this line of investigation we can ultimately formulate ways to keep diseases from starting.”
People who are better at coping with stress than others are often considered resilient. The goal of the study therefore was to look at resilience and see how it affects people. With the development of new technologies and analytical methods, such as machine learning algorithms, that can account for large datasets and variables, Dr. Church’s team was able to examine resilience using multiple angles.
They defined resilience using the Connor Davidson Resilience Scale (CDRISC), a 10-item self-report questionnaire that measures positive acceptance of change, tolerance of negative affect, tenacity and the ability to recover after stressful events.
Overall, five factors of resilience were measured:
They also used multimodal MRI to look at different aspects of the brain, including structure, function, and connectivity between different brain regions. Through fecal samples, they were able to assess different aspects of the microbiome, such as abundance (what bacteria were present and how much), what those bacteria produce (metabolomics), and what their function is (transcriptomics).
With all this information, they found that, quite simply, resilience is a whole-body phenomenon that not only affects the brain but also the microbiome and what metabolites it’s producing.
Their analyses showed that people who had high resilience levels had lower levels of depression and anxiety, higher frequency of bacterial transcriptomes, and increased metabolites and cortical signatures, such as increased resting state functional connectivity between reward circuits and sensorimotor networks and decreased gray matter volume and white matter tracts within the emotion regulation network—all positives.
There are still many questions to answer. “Our findings suggest that resilience impacts psychological symptoms, emotion regulation and cognitive function, that the microbiome is critical in shaping resilience, and that microbiome modifications have the potential to increase resilience to psychological stress,” Dr. Church explained. “However, we don’t yet know which comes first, whether resilience promotes a better gut microbiome or a better microbiome helps people be more resilient.
We will need longitudinal studies to look at changes before and after chronic and acute episodes of stress to understand more. But Dr. Church’s team was able to show that, in a single time point in a cross-sectional study, there is an influence of resilience on both the gut microbiome and the brain, with this important
takeaway: Resilient people not only manage stress, but in turn, are also better able to fend off both emotional and physical ailments.
While there’s more to learn about the brain-gut-resilience connection, you can take steps right now to bolster your stress tolerance, ease the burden of stress on multiple body systems, and improve both your health and psychological well-being.
Consider interventions that are multipronged and multifaceted, targeting the brain and/or the gut microbiome.
Resilience programs. For example there are programs to boost resilience to reduce stress.
One example is SMART, the Stress Management and Resiliency Training program developed by the Benson-
Henry Institute for Mind Body Medicine at Massachusetts General Hospital, which can be taken online. The SMART program includes three individual appointments, which are reimbursed by most insurers. The program also includes eight weekly two-hour group sessions, which are self-pay.
There is a free online training program at https://resiliencetraining.net/p/free-online-resilience-training.
Diet. The most influential and easiest way to impact your gut microbiome and, in turn, your brain, is through diet. You can support the gut-brain connection by incorporating a balanced and diverse diet rich in fruits and vegetables that provide fiber, probiotics, omega-3 fatty acids and antioxidants, while minimizing consumption of processed foods, added sugars, artificial sweeteners, excessive alcohol and antibiotics. Dr. Church recommends making mindful dietary choices by counting and getting in 30 different vegetables and fruits per week to help maintain a healthy gut microbiome and support optimal brain function and mental well-being.
