Anyone who gets stomach aches in moments of high stress knows how much the brain influences the gut. However, recent research shows that the connection may work both ways. Within the gut is a second “brain” called the enteric nervous system (ENS), which communicates with the true brain in your skull.
As experts learn more about the gut-brain axis, they've developed a much better understanding of the links between mood, health, diet, digestion, and even mental illness.
Unlike the actual brain, the ENS is not responsible for any cognitive ability. It is essentially just a control system of millions of nerve cells that line the gastrointestinal tract from the esophagus to the rectum.
The main purpose of the ENS is to control digestion, including all of the minor functions that allow the process to occur, such as swallowing and the release of the enzymes responsible for breaking down food.
Within the gastrointestinal tract is a delicate system of microbes that helps facilitate many gut functions. This microbiome can release certain substances that enter the blood, just like nutrients from food. These bacteria can also use nerve connections between the ENS and the brain to send signals.
Alternatively, gut bacteria can also stimulate the gut’s immune system cells, which then send signals to the brain.
For many years, some doctors have believed that issues like bloating, pain, constipation, diarrhea, and major conditions like irritable bowel syndrome (IBS) were the result of depression and anxiety. By researching all of the functions of the ENS, experts have discovered that the other way around may also be true: bowel conditions can cause anxiety and depression.
Researchers have found that serious gut conditions like IBS involve increased permeability in the gut, which allows the gut microbiota to encourage irritation and inflammation that then influence the brain.
Scientists still have much to learn about the various microbes in the gut and the overall gut-brain connection. However, some of the more concrete findings show that a person can improve their mental health by adjusting their diet. Gut bacteria can produce hormones that affect the brain and influence how the brain produces them.
A diet rich in prebiotics and probiotics alters the gut bacteria and can improve mental health symptoms. Beyond that, certain foods may limit inflammation in the gut, which could also help with these conditions. Some experts refer to these mental health-boosting bacteria as psychobiotics.
New understandings of the gut-brain connection may allow for treatments for conditions beyond mood disorders. “Bottom-up” treatments target the gut to treat the brain. They are still under development and may use many different techniques.
For example, the brains of people with Parkinson’s disease contain high levels of synuclein—a substance that comes from the gut bacteria. It may be possible to limit our vulnerability to Parkinson’s disease by limiting the transfer of synuclein from the gut to the brain.
In addition to targeting the gut to heal conditions of the brain, many doctors are treating the gut by targeting the brain. For many years, medical professionals have treated conditions like IBS by reducing stress levels and symptoms of depression and anxiety. Antidepressant medications help improve gut motility, sensitivity to abdominal pain, and how fast food moves through the gut—all of which improve IBS and depression symptoms.
For people with gut issues, psychotherapy may also be an impactful treatment method. Cognitive behavioral therapy focuses on challenging counterproductive thoughts and learning coping skills to manage anxiety and stress levels. Many experts find that extreme pain from conditions like IBS stems from pain catastrophizing, meaning that people expect the pain to be severe, so it is.
Behavioral therapy helps adjust the patient's mindset to avoid pain catastrophizing and limit pain. Alongside behavioral therapy, relaxation therapy uses music, muscle relaxation, and positive visualization to improve mental health and alleviate gut symptoms. Even hypnotherapy is growing in popularity for treating gastrointestinal issues.
Just like with mental conditions, sometimes behavioral therapy does not suit certain individuals and their unique gut needs. Behavioral therapies are often short-term interventions. Though many people benefit from their effects for the years afterward, some individuals may find that the timeframe simply is not effective for them.
Additionally, some people may have physical symptoms beyond the treatment capabilities of behavioral therapies alone.
Because so much is still unknown about the gut-brain connection, researchers are exploring many avenues that combine brain and gastrointestinal treatments. A major area of interest is discovering how gut-brain signals affect metabolism. Understanding these connections would allow doctors to treat nutritional issues, obesity, and major conditions like type 2 diabetes.
This site offers information designed for educational purposes only. You should not rely on any information on this site as a substitute for professional medical advice, diagnosis, treatment, or as a substitute for, professional counseling care, advice, diagnosis, or treatment. If you have any concerns or questions about your health, you should always consult with a physician or other healthcare professional.