Facts about the Gut-Brain connection you should know

“Having a gut-wrenching experience,” “feeling butterflies on your stomach,” or “following your gut.”

These expressions exist for a reason – the gastrointestinal tract is quite sensitive to emotion. Feelings of anger, sadness, stress, or excitement can affect our gut.

This article will explore the two-way relationship between the brain and the gastrointestinal (GI) system to understand how it affects our physical and mental health.

Effect of emotions on Gut’s health

Some people may feel nauseated before an important presentation or feel intestinal pain during stressful situations. These GI disturbances are real and can interfere with the person’s productivity and quality of life(1).
These problems result from the interaction between physical and psychological factors, which can influence gut physiology, affecting its movement and contraction and producing discomfort(1).

The reciprocal relationship between Gut and Brain

Our second brain: the role of the enteric nervous system

The link between digestion, mood, and health relies on a double layer of millions of nerve cells covering the GI tract from the esophagus to the rectum. Scientists call it the enteric nervous system (ENS), or the gut’s brain(2).

The ENS has many functions, including controlling digestion and blood flow in the GI tract and modulating immune and endocrine functions(2).
Although the second brain can’t think or make decisions, it communicates with our brain triggering emotional changes. For example, evidence shows that irritation in the GI system can send signals to the central nervous system (CNS) and trigger mood changes(2).

These findings could explain why people with irritable bowel syndrome (IBS) are more likely to develop depression and anxiety(2).

Gut microbiota

The gut microbiota consists of trillions of microorganisms that live in our intestines. We acquire most of this bacterial population during birth. But antibiotic use and other factors can influence these microorganism’s levels(3).

Studies show that gut microbiota can affect behavior and emotion. For instance, a probiotic bacteria called Lactobacillus rhamnosus releases GABA. This neurotransmitter helps regulate brain activity and relieve anxiety. Rats that consumed this probiotic displayed a more relaxed behavior than those that didn’t. According to the researchers, the bacteria affected the animal’s brain chemistry(3).

Gut-brain relationship, GI conditions, and mental health

Understanding the mutual relationship between the gut and the brain helps clinicians improve the treatment of diseases of the GI tract from a more integrative perspective(3,4).

For example, patients with GI distress may benefit from relaxation techniques, cognitive behavioral therapy, and medication to treat mood disorders like depression and anxiety(5).

At the same time, dietary and lifestyle changes that help maintain a healthy microbiota may help alleviate mood disorders. This includes(4):

• Eating plenty of fresh food and vegetables, whole grains, and nuts.
• Avoiding excess intake of meat, dairy, and processed foods.
• Consuming food rich in fiber and fermented food a few times a week.
• Eating fish, especially those rich in omega-3 fatty acids.

Probiotics may also help reduce the symptoms of depression, but more research is needed to conclude(4).

Scientists believe that the focus should be on the entire diet, and no superfood can guarantee positive mental health results(4).

References

1. Harvard Health Publishing. The gut-brain connection. https://www.health.harvard.edu/diseases-and-conditions/the-gut-brain-connection#:~:text=The%20brain%20has%20a%20direct,send%20signals%20to%20the%20gut. 2021.
2. Johns Hopkins Medicine. The brain-gut connection. https://www.hopkinsmedicine.org/health/wellness-and-prevention/the-brain-gut-connection. 2022.
3. NIH. 4 Fast Facts about the Gut-Brain Connection. https://www.nccih.nih.gov/news/events/4-fast-facts-about-the-gutbrain-connection. 2022.
4. Nature. Could a better diet improve mental health? https://www.nature.com/articles/d41586-020-03447-2. 2020.
5. Cleavland Clinic. Gut-brain connection. https://my.clevelandclinic.org/health/treatments/16358-gut-brain-connection. 2020.