Is the Gut-Brain Connection Real?

Is the gut-brain connection real? When’s the last time you had a gut feeling? What did it feel like exactly, and where? Perhaps it was a tug in the pit of your stomach that reached up your body and into the corners of your mind. Or maybe it traveled the other way, and the thought of something in your mind’s eye released a handful of butterflies into your stomach.

The gut-brain axis

The gut-brain axis (GBA) refers to the “bidirectional communication between the central and the enteric nervous system, linking emotional and cognitive centers of the brain with peripheral intestinal functions” (National Library of Medicine). In other words, the gut-brain axis is the active line of communication between the trillions of microbes in our gut and the complex world inside our brains. The gut-brain connection has been a topic of growing scientific interest and research over the past decade or so, although the deeply interconnected nature of the two systems was recognized and has been honored much earlier in the non-western world. Scientists and researchers are uncovering the extent of the communication between the mind and the gut, as well as how that relationship can impact the presentation and treatment of gastrointestinal and mental health conditions. Both our brains and our digestive systems are important to our survival. The two work together to make sure we are getting the nutrients needed to function in our environment. If you were to eat something rotten or expired, the pain and discomfort in your stomach would alert the brain that it is something to avoid in the future. More than just fight or flight survival, the mind and body communicate in more complex and sustained ways and “this feedback loop is especially strong between your brain and gut” (Cleveland Clinic).

What is the gut brain axis?

The gut-brain axis includes the Enteric Nervous System (ENS). The ENS is a part of the autonomic nervous system that controls the functions of our internal organs. More specifically, the ENS operates in the gastrointestinal region and regulates digestion. The vagus nerve helps connect the ENS to the brain. The vagus nerve helps pass sensory information about the conditions in your gut through the ENS and into your brain. It can then send motor signals from the brain to the gut (Cleveland Clinic). This incredible system operates largely outside of the brain and nervous system yet contains 100 million nerve cells in the gastrointestinal tract. There are more nerve cells in your gut than anywhere else in your body outside of your brain – no wonder the ENS is also called “the little-brain” (Cleveland Clinic). While it doesn’t have the same sort of thoughts that we associate with our brains, our “little brain” does send messages through the GBA straight to the brain which then impacts our brain functions, including thoughts, emotions, and memory. Another important player in the BGA is the gut microbiome. This incredible system is made up of the trillions (that’s right, TRILLIONS!) of microorganisms, also called microbes, such as bacteria, viruses, and fungi, that all exist in the gut. Dysbiosis refers to the imbalance of microbes in the gut, an imbalance which can lead to a variety of health outcomes. Research has shown a link between the makeup of the gut microbiome and gastrointestinal disorders, such as Irritable Bowel Syndrome (IBS), anxiety and depression, chronic stress, chronic fatigue, and even neurodegenerative diseases such as Parkinson’s disease.

How do the mind and the gut communicate?

While it is true that mental states like nervousness, anxiousness, and distress can release chemicals into the digestive system that trigger things like indigestion, constipation, and nausea, dysregulation in the gut can also impact the immune system and central nervous system that in turn trigger mood changes. Bacteria in the gut can produce neurotransmitters that travel through the bloodstream to the brain. One of these neurotransmitters includes serotonin, which helps regulate mood, sleep, and memory. Overgrowth in the gut of a set of microbes called Eggerthella has been found to be associated with depressive symptoms (UCLA Health). Findings like these might help explain why a disproportionate number of people with IBS report depression and anxiety.  Another recent finding connects the function of the gut to cognitive symptoms of long COVID. Scientists at the University of Pennsylvania just released a study that points to lingering remnants of the COVID virus in the gut reducing serotonin production, and “depleted serotonin could especially explain memory problems and some neurological and cognitive symptoms of long Covid” (New York Times).  How do healthcare providers address issues in the gut and brain? While gastroenterologists and mental health therapists may seem like two very different positions, they both help us help our brains, both big and little, function and thrive, and understanding the connection between the mind and the gut can help us find the most effective treatments for different kinds of disorders. Digestive conditions can be helped by things such as therapy and antidepressants, and taking care to take care of our guts can in turn help our mental health. For example, gastroenterologists may prescribe antidepressants for patients with IBS ”not because they think the problem is all in a patient’s head, but because these medications calm symptoms in some cases by acting on nerve cells in the gut” (Johns Hopkins), and mental health therapists may use Cognitive Behavioral Therapy (CBT) to help patients adjust thinking patterns that may contribute to physical symptoms. Having a therapist to talk to to help address mental health can improve gastrointestinal symptoms, and having a doctor look into how to improve our gut functioning can affect our overall mental health. 

How can I help my mind and my gut?

• Mindfulness and Relaxation therapy
  • Somatic based mind-body therapies can help people find techniques to relax their body in ways that improves gut performance.

• Relax after eating to more effectively digest food.
  • Lots of us eat on the run or quickly, but slowing down to eat can help us appreciate that while the mind may forget about the food as soon as it is swallowed, the body continues to process and digest it long after your meal is over.
• Satisfy your taste buds, your mind, and your gut!
• • Getting your gut the nutrients it needs can be a delicious endeavor! Below are some foods that have been shown to improve gut and brain health.
    • Fiber
      • Includes: beans, oats, nuts, dark chocolate, fruits, and vegetables.
      • Why? These foods not only feed us but feed the microbes in our gut which helps keep our bowels regular and nourishes the gut lining.
    • Protein
      • Includes: eggs, milk, yogurt, turkey, fish, broccoli, oats, and nuts.
      • Why? Proteins contain nitrogen, which helps control the amount of bad bacteria in the microbiome. It can also contribute to the production of serotonin, which is great for the brain!
    • Probiotic and prebiotic foods
      • What? Yogurt, kefir, kimchi, pickles, kombucha.
      • Why? Gut bacteria love to feast on fermented foods!
    • Omega-3 fatty acids
      • What? Walnuts, flax seeds, salmon, sardines.
      • Why? Omega-3 fatty acids can help lower cholesterol and increase memory and cognitive function.
• Move your body
  • I know, I know – we hear it all the time. Movement and exercise are helpful for both the body and the mind. But this doesn’t mean you need to go to the gym five times per week! Taking small breaks for movement during the day can do wonders for both mental and physical health.
• Don’t forget water!
  • In addition to all of the other reasons water is important for us and our survival, it helps facilitate the digestive process.

There is still a lot we don’t know about how exactly our mind and gut impact one another, but it is clear that they are constantly communicating, and those messages impact both our mental and digestive health. Being aware of this and using multiple modalities to target mental health and gastrointestinal issues can help us better find ways to alleviate symptoms and appreciate the deeply interconnected nature of our bodies and minds.  Blog written by Sentier Client Care Coordinator, Ellie Struewing, BA