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How The Brain And Gut Are Connected

By Sara Novak

Ever wonder why when you get nervous it feels like there are butterflies flying around your stomach? Maybe you have trouble eating or when you do eat, your stomach feels crampy or you even have diarrhea. We hear so many terms thrown around nowadays with regards to gut health that it can be difficult to know what it all means. Are the brain and the gut really connected? We have long known that gut health was closely linked to digestion and even immune health, but now we are more and more aware of the fact that our gut, and particularly the balance of good and bad bacteria, has a lot to do with our mental health. In fact, the gut has its very own nervous system. Your depression and anxiety may have more to do with what is going on in your gut than you ever thought possible. Let’s take a closer look.

Table Of Contents: 

What Is The Gut Brain Axis?:

gut brain axis the connection between brain and gut

It is called the gut brain axis and it is the communication that takes place between the central nervous system and the enteric nervous system. The enteric nervous system is located in the gut. It is a mesh-like structure of nerves and neurons that is partially responsible for the body’s autonomic nervous system. It blankets the gastrointestinal tract. According to a study published in the Annals of Gastroenterology, “strong evidence suggests that gut microbiota has an important role in bidirectional interactions between the gut and the nervous system. It interacts with the central nervous system by regulating brain chemistry and influencing neuro-endocrine systems associated with stress response, anxiety and memory function.” The bottom line is you are what you eat both mentally and physically. 

Read More: 5 Supplements That Reduce Cortisol Levels

The Connection Between The Brain And The Gut:

how the brain and gut are connected

Unlike the brain, the enteric nervous system is not necessarily capable of doing math equations or writing a book report, but it does truly have a mind of its own. The enteric nervous system controls the body’s automatic responses to digestion. It releases the digestive enzymes necessary to break down food and controls swallowing and blood flow. The latest research shows that it is also capable of communication with the central nervous system and the brain in ways we never thought possible before. 

According to Johns Hopkins Medicine, “the enteric nervous system may trigger big emotional shifts experienced by people coping with irritable bowel syndrome (IBS) and functional bowel problems such as constipation, diarrhea, bloating, pain and stomach upset.” We have long thought the butterflies in the stomach were caused by anxiety, but now we are finding that it may be the other way around. Our gut may cause anxiety and depression instead of anxiety and depression impacting the gut.

Additionally, we know of other indicators between the gut and brain health. For example, when you are daydreaming about biting into a sweet, juicy piece of watermelon, your stomach is already priming the digestive juices for foods that have not even reached the gut. Additionally, according to Harvard Health, “many people with functional GI disorders perceive pain more acutely than other people do because their brains are more responsive to pain signals from the GI tract. Stress can make the existing pain seem even worse.”


Why Gut Health Matters:

With all these connections, you can easily see why gut health matters but let’s look at the research. 

1. Diarrhea

diarrhea and stress connection the brain and gut

This is an obvious one, but it is still worth mentioning. Your gut is made up of good and bad bacteria. Lactobacilli is the most abundant good bacteria found in the gut. When your gut is flush with these good bacteria, it has a huge impact on your digestive health. In particular, lactobacilli have also been shown to improve symptoms of diarrhea. A review published in the journal Pharmacological Research found that probiotics may be effective at treating children who have diarrhea as a side effect of taking antibiotics. Another study published in the journal Revista Española de Quimioterapia found that lactobacillus “demonstrated its beneficial effect on antibiotic associated diarrhea by delaying the onset of diarrhea and showed a tendency to decrease the number of daily stools versus placebo.” Another study published in the Journal of Gastroenterology found that taking probiotics containing lactobacillus reduced the duration of diarrhea by a day. 

2. Irritable Bowel Syndrome 

Irritable bowel syndrome and the brain and gut connection

Poor gut health has also been associated with irritable bowel syndrome or IBS. A study published in the journal Baillière's Best Practice & Research found that “the intestinal microbiota interacts with several aspects of gastrointestinal function that may affect the expression or progression of IBS.”  Another study published in the Journal Gastroenterology Clinics of North America found that “irritable bowel syndrome is regarded as the prototypic disorder of the brain-gut-microbiota axis that can be responsive to probiotic therapy.” 

Learn More: Lactobacillus: The Strain To Amazing Gut Health

3. Anxiety And Depression

anxiety and depression and the brain and gut connection

More and more research is showing that depression and anxiety are closely linked to gut health. A study published in the journal Neurotherapeutics found that the body’s immune response was closely linked to the secretion of oxytocin. When the body does not release enough oxytocin, it promotes an acute stress response which has been shown to negatively impact gut health. A study published in the Journal of Neuroscience Research found that “the study of the gut microbiome has increasingly revealed an important role in modulating brain function and mental health.” Finally, a study published in the journal Nutrients found “that gut probiotics play a major role in the bidirectional communication between the gut and the brain. Probiotics may be essential to people with depression.” 

4. Autoimmune Diseases 

autoimmune issues and the brain and gut connection

When the immune system perceives a threat from its own immune system, it can cause it to attack itself for one reason or another. According to a review published in the International Journal of Immunopathology and Pharmacology, “in recent years there have been increased rates of autoimmune diseases, possibly associated to altered intestinal microflora.” A study published in the Journal Nature Reviews Immunology “raises the possibility that the mammalian immune system, which seems to be designed to control microorganisms, is in fact controlled by microorganisms.” This means that immune health is controlled by microorganisms populating the gut, rather than the other way around.  

5. Weight Management 

weight management

Another important way that the gut and the brain connect is in what you eat. That is why the gut brain axis is closely linked to weight loss and weight gain. Some research has even shown that the makeup of the microbiota is different in those that are considered obese. A study published in the journal Cellular and Molecular Life Science found that “gut microbiota may participate in energy metabolism through energy harvest from the diet, regulation of fat storage, regulation of lipogenesis, or regulation of fatty acid oxidation.” Other research has shown that changes in the intestinal microbiota may trigger some of the inflammation that results from obesity and may be linked to leaky gut.

6. Skin Health

skin health

Good gut health has also been linked to healthy skin. Your skin is the body’s largest organ and this is one of the first places that poor gut health may show up. Atopic dermatitis, often called eczema, is a great example. It is a skin issue that’s common in children. It tends to be long lasting and flare up periodically. The autoimmune disorder appears as redness and irritation on the skin. Those with eczema are also more likely to have other allergies whether they be food allergies, asthma, or allergic rhinitis. A study in BMC Childbirth Pregnancy found a “growing body of evidence for the benefits of probiotics in prevention of eczema.” Other research has shown that children who have eczema had a different microbiota compared to children that did not, though more research needs to be done on the subject.

Foods For Good Gut Health:


Fermented foods are some of the most important foods for improving gut health. A review published in the journal Nutritional Neuroscience found that “fermented foods hold promise as a dietary intervention due to their potential to modify the gut microbiota and improve the integrity of the intestinal barrier.” Fermentation is an ancient process that breaks down the sugars and starches found in carbohydrates using bacteria and yeast. Fermented foods are easier for the body to digest and even more importantly, they populate the gut with good bacteria. Try these fermented foods:

  • Kefir
  • Yogurt
  • Kimchi
  • Kombucha
  • Sauerkraut 
  • Cottage cheese (some but not all)
  • Pickles 
  • Pickled foods 

Tips For Improving Gut Health:

1. Stress Management

stress management

Stress management is linked to good gut health. Chronic acute stress response has been shown to impact all parts of the body including the gut. Find ways to manage your stress levels. These include yoga, meditation, deep breathing, chanting, qigong, surfing, hiking, talk therapy, and time spent with friends. View your stress level as just as important to your health as your blood pressure and your weight. 

2. Sleep


If you are worried about your gut health, make sure that you get enough sleep. A study published in the journal Sleep Medicine Reviews found that “the microbes of the gastrointestinal tract exhibit circadian rhythm, and their composition oscillates in response to the daily feeding/fasting schedule.” This is a big deal because it shows that the body’s circadian rhythms are closely linked to the bacteria found in your gut. While the research on this is still relatively new, there is even some indication that taking probiotics may also help with sleep quality and duration. 

3. Probiotics 


Taking a probiotic has been shown to improve gut health. It helps to populate the gut with good bacteria that are needed for good digestion and a host of other issues. A study published in the journal Médecine et Maladies Infectieuses found that “close relationships between gut microbiota, health, and disease, have led to great interest in using probiotics to positively modulate the gut microbiota to prevent or treat some diseases.”

Read More: Top 4 Probiotics For Women

4. Change Your Diet


Processed foods have been shown to negatively impact gut health. Choose living foods loaded with the nutrients necessary to promote good gut health. These include fruits, high quality protein, tubers, squash, MCT oil, and ghee. 

5. Exercise 


The makeup of the microbiome has been closely linked to whether or not you exercise. According to a study published in the journal Exercise & Sport Sciences Reviews, “over a dozen controlled animal studies have shown that exercise training independently alters the composition and functional capacity of the gut microbiota.” Another study published in the Journal of Sports Health Science found that "gut microbiota may play a key role in controlling the oxidative stress and inflammatory responses as well as improving metabolism and energy expenditure during intense exercise.”