Iowa Specialty Hospital

Gut - Brain Connection

October 12, 2023

News Item Image

Most people do not automatically think that something going on in their gut could be affecting their mood, or that their emotions could be affecting their gut. We have all experienced the connection, however. People report feeling like they have butterflies in their stomach when they feel nervous or have a gut feeling about a situation or decision. We have a nervous system in our digestive tract called the Enteric Nervous System. It is also referred to as our second brain [1].  The gut is connected to the brain in three ways:  the immune system, the vagus nerve, and through hormones. That explains why there is so much communication between the two systems.

The role of diet and gut health in relation to our mental health is emerging and is a focus of research. Our gut and brain are connected from the start because they form from the same tissue during development. Our gut contains many organisms including bacteria, viruses, and fungi, and they start to colonize at birth. Which organisms develop depends on several factors, including genetics, how the baby is delivered, the baby’s diet, and cleanliness of the environment [2]. The colonization is complete by age three and is called our Gut Microbiota.

Different factors affect the balance of our gut microbiota throughout our lives. The term dysbiosis refers to imbalance in the microbiota. When we experience dysbiosis, there is less diversity of organisms, less beneficial organisms, and more potentially harmful organisms [3].

We know stress or trauma early in life can affect our mental health. Research now shows stress can change the balance of organisms in our gut. These changes in the gut can affect how we handle stress in the future and can lead to chronic inflammation. This can make individuals more susceptible to conditions like posttraumatic stress disorder or depression. In addition to stress, antibiotics, poor diet, infections, and alcohol use can cause dysbiosis. When the balance is disrupted, the gut can become leaky. The gut lining normally allows for nutrients to be absorbed from our gut while maintaining a system of tight junctions that protect us from all the bacteria in our gut. Leaking activates the immune system which creates inflammation. Short-term inflammation helps us heal, but chronic inflammation has been linked to depression and other health problems.

Most of our serotonin is produced in the gut due to interactions between the gut lining and the microbiota. When our balance is off, we produce less serotonin and our mental health suffers.

Antidepressants do help many people with symptoms of depression but not everyone sees benefit. Sometimes we have to look at other forms of therapy or other things that may be going on in order to treat depression. Psychotherapy is an important component of treatment that helps to examine thoughts, feelings, and behaviors. Changing thought patterns can in turn help depression. Another important factor in treatment is lifestyle. We can help our gut microbiota stay in balance by avoiding and/or limiting use of tobacco and alcohol, managing stress, maintaining a healthy weight, getting enough sleep, eating a healthy diet, and exercising regularly. All of these lifestyle factors help foster a rich, diverse gut microbiota, decrease inflammation, and hopefully help our mood.




  2. Ursell, L.K., et al. Defining the Human Microbiome. Nutrition Reviews. 2012 Aug: 70 (Suppl): S38-S44.
  3. Hrncir, T. Gut Microbiota Dysbiosis:  Triggers, Consequences, Diagnostic and Therapeutic Options. Microorganisms. 2022 Mar;10(3)578. Pub online 2022 Mar 7.

             doi: 10.3390/microorganisms10030578.

« Back

© 2024 Iowa Specialty Hospital. All rights reserved.