Understanding the Gut-Brain Connection: The Impact on Mental Health

Mental health conditions like depression, anxiety, bipolar disorder, and others are influenced by many factors. One key factor is the “Gut-Brain Connection,” a direct link between mental health and the overall health of the gut. (“Gut” refers to a person’s gastrointestinal system, including their stomach, intestines, and colon, while “brain” refers to the central nervous system.) Managing our mental health is not always as simple as changing our diet, but there is a direct link between the food we eat and how we feel. 

Hippocrates, the founder of modern medicine, once said, “All disease begins in the gut.”

Have you ever felt suddenly nauseous just before going to make a presentation? Ever felt the pangs of nervousness and then needed to run to the bathroom? Or had no appetite during a time of high anxiety? Have you experienced “butterflies” in your stomach when running into your crush? That’s the gut-brain connection at work. Unpleasant emotions like fear, shame, and anxiety influence digestion. And the inverse is also true: poor diet and lifestyle choices influence our moods and overall emotional state. For example, chronic stress, lack of sleep, and a sedentary lifestyle influence not just our physical body, and our mind and emotions as well. 

The Gut Microbiome

Did you know that the majority of the “feel good chemicals” in our body, serotonin, and dopamine, are stored in the digestive tract? (Serotonin and dopamine are neurotransmitters that affect our central nervous system, including our brain.) Studies show that more than 90% of the serotonin and 50% of the dopamine in the body are produced and stored in the gut! Naturally, they are influenced both positively and negatively by our gut bacteria. 

We also have something called the gut microbiome, an ecosystem of trillions of microorganisms, particularly bacteria, which reside primarily in the large intestine. The food we eat feeds these bacteria, enabling them to produce those chemicals that yield great power over our mood and behavior. Your gut is ALIVE. In addition, our digestive tract is lined by a mucosal layer that serves as a home and source of food for the gut microbiome. The mucosal layer also acts as a physical barrier, keeping gut bacteria from infiltrating organs and causing infection and inflammation. Thus, we should not underestimate how powerful our gut health is to our mental well-being. 

“Leaky Gut” and Inflammation 

The mucous lining of our intestines is semi-permeable and is designed to absorb water and nutrients from our food into our bloodstream. But this protective layer can lose its integrity or become compromised by certain foods, antibiotics, stress, and even lack of sleep. For these and other reasons, some people have increased intestinal permeability or hyperpermeability. This may lead to something called “leaky gut.” (Leaky gut syndrome is not yet recognized as a diagnosable condition, but research is ongoing.) When the gut lining is impaired, food particles, toxins, and bacteria can leak into the bloodstream and cause a systemic inflammatory response. Acne, rashes, arthritis, chronic fatigue, asthma, diabetes, mood changes, and other health conditions can occur. Studies show a direct link between chronic inflammation in the body and symptoms of depression. 

What Can You Do About the Gut-Brain Connection?

Well, when you eat think of it as feeding your gut, and in turn, feeding your brain. Remember that your gut is alive. It is full of living bacteria and microbes that need to be fed nutrient-dense foods that help it stay balanced and thriving so you can feel your best. 

People who eat a diet high in ultra-processed foods like pre-packaged foods, microwave dinners, snack cakes, crackers, soda, candy, potato chips, ice cream, fried foods, fast food, and enriched cereals are adding sugar and artificial chemicals to their system, which affects the gut and gut lining. Here are foods that can make a positive difference to your physical and mental health.

Foods That Support a Healthy Gut-Brain Connection

• Fermented foods (e.g., plain yogurt, kefir, kombucha, kimchi, sauerkraut)
• Healthy fats (e.g., walnuts, avocados, flax and chia seeds, olives, and oily fish)
• Fruits and vegetables  
• Garlic and onions
• Green tea
• Berries
• Leafy Greens
• Grass-fed meats and wild seafood 

One barrier to fitting more of these foods in your diet could be cost. For affordable foods that support the gut-brain connection read our blog. 

Generally, avoid foods that are processed with chemicals and additives like sugar and oils (e.g., granola bars, baked goods, and pre-packaged foods). Specifically, try to avoid or limit

• White refined sugar 
• Alcohol 
• Gluten
• Processed and packaged foods 
• Anything that has a lengthy list of ingredients, many of which you may not even be able to pronounce. 

Processing brings a food far away from its original form. Think of an apple, a sweet potato, or a piece of steak. They do not have an ingredient list because they are in their most natural state. Aim to include more of these unprocessed foods in your diet.

Start Where You Are

Mental health conditions are a complex issue influenced by a multitude of factors like genetics, environment, family history, childhood trauma, and physical health.  There is ample research showing a strong connection between our physical health and our mental and emotional well-being. We make choices every day about what foods go into our body, making it an aspect of health that we can control (within the limits of food availability, cost, etc.). 

As a person who struggles with mental health issues, finding ways that I can help myself now is always of interest. In a society looking for a quick fix, instant gratification, and results, improving the quality of the food we eat could be the first step in improving our overall emotional state. Sometimes finding the will to eat at all when you have depression is its own battle. Start simple and start where you are. The gut-brain connection is a concept that is underrated in its power to change lives and help ease symptoms of some of the most common mental health conditions that plague so many of us today.

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Allison Paganini RN, BSN has worked as a nurse in the New England area for 9 years in Acute and Long Term care. Her skills and knowledge of medicine coupled with a lifelong passion for writing led her to pursue a career as a Health Content Writer. With a particular interest in functional and holistic medical practices, as well as nutrition. Allison is interested in writing about a multitude of different health topics as it relates to the mind-body connection and lifestyle practices that influence both mental and physical well-being. She currently works as a nurse at Emerson Hospital in Concord. She lives with her Husband Gabriel and dog Benny in Watertown, MA. She is also expecting her first child, Isabelle Marie in October 2024.