The Gut-Mind Connection, Stress and Mental Health

Written by Chris Claussen, Co-Founder, Chief Innovation Officer


About the Author: Chris has over 20 years of experience in product and business development. For the past five years he has focused exclusively on innovative product development in the functional foods and functional mushrooms space. Chris brings experience exploring, experimenting, and conducting extensive research on the relationship between functional foods/ mushrooms and metabolic, brain, and mental health.​


October 10th marks World Mental Health Day, dedicated to raising global awareness about the importance of mental health. It's a day to reflect on the critical issues surrounding mental well-being, emphasizing the need for understanding and support. On this day it’s essential to recognize that mental health and physical health, though often treated as separate entities, are profoundly interconnected through a myriad of synergistic mechanisms. One of these crucial mechanisms is the gut-brain axis, a bidirectional communication system that connects the gastrointestinal (GI) tract with the central nervous system (CNS) in the brain.  This intricate network relies on a complex interaction of hormones, neurotransmitters, and receptors found throughout both the gut and the brain. Understanding this connection is vital because it highlights the holistic nature of health. Mental well-being is not an isolated concern but is intimately entwined with our physical health.

Serotonin and dopamine are well known brain neurotransmitters which, when in low supply have been linked ADHD, anxiety, and depression. But did you know that 90% of the body’s serotonin and 50% of dopamine is made it the digestive tract?  In fact, there is a network of neurons lining our guts that is so extensive some have nicknamed it our "second brain". This intricate neural network accomplishes far more than simply managing digestion or occasionally inducing nervous sensations. The “second brain” residing in our gastrointestinal system, working in tandem with the brain in our head, significantly influences our mental well-being.  When there's an imbalance within the gut, it can disrupt the delicate production of neurotransmitters, potentially leading to mood disorders and other mental health issues. This revelation underscores the significance of maintaining a healthy gut, not just for digestive comfort but for our overall well-being. 

Chronic stress can harm both the gut and mental health as the gut-brain axis plays a crucial role in the body's stress response. Chronic stress affects the gut-brain axis by negatively altering the composition of gut microbiota, known as gut dysbiosis.  Gut dysbiosis occurs when there's an imbalance between beneficial and harmful bacteria in the gut. The altered gut microbiota from chronic stress can trigger inflammation, reduce neurotransmitter production, and lead to changes in behavior and mood.  Conversely, a healthy gut can help regulate the body's stress response, reducing the risk of stress-related mental health issues.

Emeran Mayer, MD is a professor in the departments of medicine, physiology and psychiatry at the University of California, Los Angeles. Mayer is a world-renowned gastroenterologist and neuroscientist with 35 years of experience in the study of clinical and neurobiological aspects of how the digestive system and the nervous system interact in health and disease.  He wrote the book: "The Mind-Gut Connection: How the Hidden Conversation Within Our Bodies Impacts Our Mood, Our Choices, and Our Overall Health.” In the book Mayer reveals that microbes in the digestive system can influence emotions and behavior, which suggests that diseases like depression are connected to gut health.  He goes on to say that because the gut’s microbial makeup isn’t static, there are steps that individuals can take to optimize gut health. First, they should minimize systemic inflammation by avoiding sugar, artificial sweeteners, and other additives in highly processed foods. Second, include fermented foods and probiotics to help build and heal the gut lining. Third, he says to reduce stress and practice mindfulness and to avoid eating when you are stressed, angry, or sad.  

            “The brain-gut-microbiome axis links our brain health closely to what we eat, how we grow and process our food, what medications we take, how we come into the world, and how we interact with the microbes in our environment throughout life.”  ­- Dr Emeran Mayer

The profound connection between the mind and the gut, and its pivotal role in mental health, hit incredibly close to home for me. Adolescence can be challenging period that often includes significant mental stress, but when combined with gastrointestinal (GI) issues, it can quickly spiral out of control and lead to severe mental health challenges. This stark reality became painfully evident when my own child, who was previously healthy, growing, and joyful, suddenly began experiencing debilitating health problems, resulting in a 30-pound weight loss and a subsequent mental health crisis.

Throughout this trying journey, my family and I sought assistance from a diverse range of healthcare professionals, including traditional, functional medicine practitioners, and mental health specialists. Unfortunately, it was an incredibly frustrating process as we navigated the complexities and dysfunctions within our fragmented healthcare system, particularly when dealing with issues that intertwine physical and mental health.

It was only after I discovered Dr. Mayer's book and sought the guidance of a dedicated GI specialist that we finally began to glimpse the prospect of relief and recovery for my child. This experience opened my eyes to the critical importance of addressing the mind-gut connection and its impact on mental health.  I am hopeful that by acknowledging and addressing the connection between stress, the gut, and the brain we can change how we approach healthcare, fostering a more comprehensive understanding of the interconnection of mental and physical well-being.

In health,



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