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The Symbiotic Relationship of the Gut Brain-Axis and Mental Health

Have you ever seen something that literally made you sick to your stomach? Have you ever wondered what that nauseating reaction actually is? 

Gut feelings, gut reactions, and “trust your gut” moments are indicators that your gut (gastrointestinal system, to be exact) and brain are linked. This connection is known as the gut-brain axis. 

We may not always pay attention to our gut feelings. Life moves fast, and distractions are everywhere. This makes it hard to keep up with gut and mental health. When we fail to take care of one, we often neglect the other.

Many people consider different aspects of their health and well-being as standalone areas, separate from one another. While compartmentalizing these areas helps us understand them better, addressing all of them can greatly improve many aspects of your life. 

Extensive research on the gut-brain axis has allowed us to understand how the powerful connection between the gut and brain affects us physically, mentally, and emotionally. Outside stressors will never go away, but there are plenty of things you can do to take control of your gut-brain axis to improve your mental well-being. 


Gut Brain Connection

Gut-Brain Axis Explained

The gut-brain axis is the two-way connection and communication between the gut and the brain.1

Your Second Brain

There are a few things we need to understand when it comes to the gut-brain axis function. The first is ENS.

Within the digestive system, you have what’s called the enteric nervous system (ENS). Scientists refer to this as your “second brain,” because the same neurotransmitters and neurons are found in the central nervous system. ENS lines your entire GI tract,2  and is responsible for several bodily functions and your overall mental health.


Many of us hear the word serotonin, and we think “happiness” which is partly true. But it’s much more than that. Serotonin is a neurotransmitter that carries signals from nerve cells to the brain. Think of it as the body’s regulation tool for pretty much everything. It plays a key role in stabilizing mood, sleep, appetite, body temperature, digestion, and more.3 Seasonal depression, lack of sleep, and many other factors affect serotonin levels, which is why it’s so important to pay close attention to what’s going on in your body. 

Serotonin affects gut health, which in turn affects mental health. Maintaining healthy serotonin levels in the body can help prevent conditions like depression and anxiety. The body uses tryptophan, an essential amino acid to produce serotonin (and melatonin as well!). Essential amino acids are not naturally made in the body; therefore, they must be obtained through food. 

Drugs are often prescribed to boost serotonin levels in people who suffer from mental illnesses including:

  • Bipolar disorder
  • PTSD (post-traumatic stress disorder)
  • Eating disorders
  • OCD (obsessive compulsive disorder)
  • Panic disorder

Amazingly, a whopping 90% of serotonin levels are found in the gut.4 Many serotonin-boosting drugs have been linked to side effects that cause gut inflammation, harming the good bacteria in our bodies. Good bacteria fights bad bacteria, restoring the body to a healthier state. While we can’t disregard the fact that some of these drugs may greatly help certain disorders, it’s also believed that treatment through holistic healing practices, diet, and regular exercise can be more effective.

Gut Microbiome

The microbiome is the community of trillions of bacteria, viruses, and funghi that live inside the body. These microorganisms are referred to as microbiota. They stabilize and develop our immune system, help fight disease, and help us convert food to energy.5 There are several variables that affect the microbiome's composition, including diet, physical activity, lifestyle habits, drug treatment, and environment. If these variables are unstable, the health of the microbiome may suffer, causing behavioral and mental health issues.


Effects of Stress


The Effects of Stress 

While there isn’t an exact answer, there seems to be a correlation between stress and inflammation. Think about times when you’ve felt threatened, nervous, or angry. You may sweat, lose your appetite, or have a racing heart. Research has shown that when stress management, exercise, and other coping mechanisms are introduced, a decrease in inflammation can happen.  

Stress can trigger the body to change the movements of the GI tract by speeding it up or slowing it down. Oversensitivity, bloating, and other irritants can occur, making it easier for an overgrowth of bacteria to form in the gut. This can negatively affect your microbiota. That’s why GI conditions like IBS or Crohn's Disease tend to worsen with stress.

You Are What You Eat

Remember, the gut-brain axis is a two-way street. Negative emotions like fear, panic, stress, anxiety, and depression can affect your gut – just as much as the types of food you put into your body. When prioritizing gut health, a wholesome diet is key. This is a simple way to nourish the relationship of your gut-brain axis. The best part about it is, with so many different foods out there, staying consistent is easier than ever!

Again, protecting your gut begins with what you put in your body. Prebiotics and probiotics are a great addition to your diet to help with this. Prebiotics are eaten by probiotics to promote the growth of healthy bacteria. You can take them in the form of a pill, or eat foods that are high in probiotics, 

Some options include: 

  • Yogurt 
  • Kefir
  • Fermented foods, such as sauerkraut, kimchi, pickles, and kombucha
  • Miso
  • Apples 
  • Dark leafy green veggies
  • Lean protein


Food on cutting board

Diversifying your diet ensures your body will get the different nutrients it needs to function at its optimal level. This also helps you stay interested in what you're eating. 

The Mediterranean Diet has been shown to have made vast improvements in gut health.6 Many foods found in the diet contain powerful anti-inflammatory properties, have healthy fats, are low in sugar, and are super tasty! 

A Low-FODMAP Diet may help individuals with a very sensitive gut, or those with certain health issues like IBS (irritable bowel syndrome), bloating, or SIBO (small intestine bacteria overgrowth). People living with these illnesses are more prone to depression and anxiety. A recent study from the American Society for Parenteral and Enteral Nutrition shows that a Low-FODMAP diet significantly improved symptoms, along with fatigue, anxiety, depression, and happiness 7

As always, it’s important to talk to your physician when making changes that could affect your health.

Exercising the Mind-Body Connection 

Practicing yoga, meditation, and deep breathing can reduce anxiety and depression, and increase the internal flow of your body.8 Releasing toxins through exercise is a great way to calm the mind. This will regulate stress levels and help minimize the body's response. It’s as simple as taking a hike with a friend or relaxing in the park. Not to mention, it's fun! 

Happy Gut, Happy Brain, Happy Life 

When your gastrointestinal system and mental state work in healthy harmony, the effects can truly be life-changing. Feeling overwhelmed is part of life, and that’s okay! Challenges are essential for us to learn and grow. But life is best enjoyed when your body and mind are on the same page. Simple lifestyle changes can maximize your overall well-being and can have long term benefits for the gut-brain axis. 

There’s no shame in asking for help. We want you to be your best version of yourself. Our health coaches will help you come up with a custom plan that best fits you. 

We’re here for you!

Lilith Mesidor

Lilith Mesidor

Lilith is originally from The Hudson Valley in New York. Growing up in this area made it easy to access the outdoors, and having a healthy, active lifestyle has always been natural to her.  Her sense of adventure and curiosity has taken her around the globe, shaping her perspective on life and human connection.

After graduating from SUNY Purchase College in Westchester, NY, she moved to Brooklyn. From there, she got bit by the travel bug and spent three years traveling on and off all over the world, using NYC as her base. She backpacked solo through South America, Eastern Europe, Southeast Asia, and parts of the Middle East. After returning from a year-long stint overseas, she moved to Aspen where she spent a winter season on the slopes.

Lilith sees the value of art and incorporates it into her life by doing or seeing at least one artistic thing a week. When she's not geeking out over health and wellness, she can be found checking out a new restaurant, seeing live music, and petting every dog she sees walk by.

She currently resides in beautiful, sunny Los Angeles. 



  1. The Gut-Brain Axis Explained in Plain English by Geraldine Van Oord: Diet VS Disease 
  2. Gut-Brain Connection: Cleveland Clinic 
  3. Serotonin: Cleveland Clinic 
  4. Microbes Help Produce Serotonin in Gut: Caltech
  5. Microbiome: National Institute of Environmental Health Sciences
  6. Nutritional Psychiatry: The Gut-Brain Connection by Umadevi Naidoo, MD: Psychiatric Times
  7. Low-FODMAP Diet Observational Study: Pubmed 
  8. Brain-Gut Connection and How integrative Treatments Can Help Relieve Digestive Aiilments: Harvard