Supporting Your “Second Brain”: Evidence-Based Approaches to Supporting Mental Health Through Nutrition and Relaxation
Apr 17, 2025 By Katherine Robison
We have all likely heard colloquialisms that reference the role that our gut plays in our mental health – for example, having a “gut feeling” or “mood follows food.” We have also experienced the direct impact that food-related choices can have on well-being, as well as how our moods can impact our food choices. But what is really happening in our bodies that connects our gut health to our mental health? And what steps can we take to support the health of this important gut-brain connection?
The Role of the Enteric Nervous System in the Body
Our bodies are home to an intricate network of nerves that govern everything from basic functions like breathing and movement to complex cognitive processes. Among these networks, the enteric nervous system (ENS) plays a particularly important role. Often referred to as our “second brain,” a term coined by Dr. Michael Gershon, the ENS consists of more than 100 million neurons embedded in the lining of the gastrointestinal tract. The ENS is responsible for several different functions, including digestion, elimination, the production of neurotransmitters and blood flow among others.
The ENS communicates with the brain via the vagus nerve, forming a communication channel known as the gut-brain axis. The communication in that channel is bi-directional, meaning that information flows both from the brain to the gut, as well as from the gut to the brain, in order for both organs to perform their necessary bodily functions at any given time. It is this gut-brain axis that highlights the importance of the ENS, not only in digestion but also in regulating emotional and psychological health (Gershon, 2013; O’Rourke & White, 2019). When we experience disruptions in the ENS, such as illness or inflammation, there can be profound effects on both our digestive health and mental health.
The Enteric Nervous System and Neurotransmitter Production
Another critical function of the ENS is its role in the production of neurotransmitters. Neurotransmitters are chemical messengers that transmit signals within the brain and throughout the nervous system. These molecules play a critical role in regulating mood, cognitive function, and emotional stability. While neurotransmitters are most commonly associated with the brain, Serotonin, often referred to as the “feel-good” neurotransmitter, is predominantly produced in the gut, with approximately 90% of it being synthesized within the ENS (Young, 2007). How does the gut do this? For starters, the food we consume has a direct influence on the production and regulation of neurotransmitters, including serotonin, dopamine, and norepinephrine, which are key players in mental health.
Serotonin production in the gut is synthesized from an essential amino acid called tryptophan. Essential amino acids must be obtained through diet; our bodies can not produce them in the absence of certain dietary inputs. Dopamine, which is associated with reward and motivation, and norepinephrine, which affects alertness and the stress response, are also influenced by dietary intake. These neurotransmitters rely on amino acids, vitamins, and minerals derived from our food to be synthesized effectively, making a balanced diet essential for emotional well-being (Pendyala, Walker, & Holt, 2012; Rogers & Kessler, 2016).
Impact of Stress and Anxiety on the Enteric Nervous System
Stress and anxiety are powerful influences on the body, and they have a direct impact on the ENS. The ENS is a subdivision of our body’s Autonomic Nervous System (ANS), along with the sympathetic nervous system and parasympathetic nervous system. When we experience stress, the body activates the sympathetic nervous system, better known as our “fight, flight, freeze” response, which has an inhibitory impact on our ENS. What this means is that, during times of stress, our body’s natural digestive processes are disrupted.
Understanding this relationship, it isn’t surprising that between 40-60% of individuals diagnosed with anxiety and roughly 50% of those diagnosed with depression have also received a diagnosis of Irritable Bowel Syndrome (IBS) during their lifetime (Gerson & Schmidt, 2009). There is also evidence to suggest a reciprocal relationship: not only can stress and anxiety impact the gut, but disturbances and imbalances in the gut can also contribute to increased stress and anxiety (Bercik & Collins, 2014).
Given the ample research highlighting the relationship between how emotional well-being impacts gut health and visa-versa, nutrition and stress management strategies can be two powerful tools used in promoting overall wellness.
Nutrition and Stress Management Techniques
To enhance the production of serotonin, dopamine, and norepinephrine, it’s crucial to include foods rich in the nutrients necessary for neurotransmitter synthesis. Below are some evidence-based dietary recommendations for supporting the production of these essential chemicals:
- Serotonin:
- Tryptophan-rich foods: Serotonin is synthesized from tryptophan, an amino acid found in foods like turkey, chicken, eggs, nuts, seeds, tofu, and fatty fish such as salmon (Young, 2007).
- Complex carbohydrates: Foods like whole grains, oats, and sweet potatoes help increase the availability of tryptophan to the brain by promoting insulin production, which facilitates the transport of tryptophan across the blood-brain barrier (Young, 2007).
- Vitamin B6 and B12-rich foods: B vitamins, especially B6 and B12, are critical in serotonin synthesis. Sources include leafy greens, legumes, eggs, and fortified cereals (Fernstrom, 2013).
- Dopamine:
- Tyrosine-rich foods: Dopamine is produced from the amino acid tyrosine, which is abundant in foods such as lean meats, dairy products, soy, eggs, and legumes (Fernstrom, 2013).
- Antioxidant-rich foods: Dopamine-producing neurons are vulnerable to oxidative stress. Foods rich in antioxidants, like berries, dark chocolate, and green leafy vegetables, can help protect dopamine-producing cells and support dopamine function (Pendyala, Walker, & Holt, 2012).
- Norepinephrine:
- Tyrosine-rich foods: Since norepinephrine is synthesized from dopamine, tyrosine-rich foods (as mentioned above for dopamine) are also beneficial for norepinephrine production (Young, 2007).
- Vitamin C-rich foods: Vitamin C is essential for norepinephrine synthesis and can be found in citrus fruits, bell peppers, strawberries, and broccoli (Pendyala, Walker, & Holt, 2012).
The use of relaxation strategies for the management of gastrointestinal discomfort has long been researched as well, and has demonstrated effectiveness (Lackner, 2004). Relaxation techniques can both help prepare the body for digestion by activating the parasympathetic nervous system as well as aid in the digestive process by supporting peristalsis and increased blood flow to digestive organs. Below are examples of relaxation techniques that are evidence-based for supporting digestion:
Bottom line
The health of our gut-brain axis is critical to both our physical and mental well-being. By engaging in evidence-based stress management techniques and attending to nutritional strategies for promoting the production of key neurotransmitters, we can support this critical gut-brain relationship and enhance overall well-being.
References:
Benton, D. (2002). Microbiota and mood disorders: Gut feelings. Psychiatry Research, 66(1), 75-81.
Bercik, P., & Collins, S. M. (2014). The relationship between gut microbiota and the brain in functional gastrointestinal disorders. Gastroenterology, 146(6), 1509-1518.
Fernstrom, J. D. (2013). The role of precursor availability in control of monoamine biosynthesis in the brain. Physiology & Pharmacology, 43(6), 410-417.
Gershon, M. D. (2013). The enteric nervous system: A second brain. Nature Reviews Neuroscience, 14(5), 349-359.
Gerson, C. D., & Schmidt, W. (2009). Irritable bowel syndrome and psychiatric comorbidities. Journal of Clinical Gastroenterology, 43(3), 215-220.
Lackner, J. M., et al. (2004). “Relaxation training and cognitive-behavioral therapy for irritable bowel syndrome: A review of the literature.” The American Journal of Gastroenterology, 99(5), 906-917.
O’Rourke, S. M., & White, D. A. (2019). Gut–brain axis and the enteric nervous system. Journal of Clinical Gastroenterology, 53(1), 1-5.
Pendyala, S., Walker, J. M., & Holt, P. R. (2012). Diet and the microbiome: The influence of dietary composition on gut microbiota and gastrointestinal health. Current Opinion in Gastroenterology, 28(2), 95-102.
Rogers, P. J., & Kessler, H. (2016). Psychobiotics: The role of probiotics in mental health. Journal of Psychiatric Research, 83, 40-42.
Young, S. N. (2007). How to increase serotonin in the human brain without drugs. Journal of Psychiatry & Neuroscience, 32(6), 394-399.
About the author: Kate Robison, LCPC is a Staff Therapist at Chicago Psychotherapy. She is credentialed as Certified Mental Health Integrative Medicine Provider (CMHIMP) and loves working with clients on examining the role that nutrition, gut health, sleep, chronic pain and movement play within their overall social and emotional well-being.
