My stomach is feeling strange, my head a bit light, and I just don’t feel up to speed. Most of us have experienced this feeling. An important presentation, an unexpected phone call, a difficult conversation, or even anticipating bad news can cause our stomach to tighten almost instantly. That’s because the brain and digestive system are in constant communication through what scientists call the Gut-Brain Axis.

The relationship between the brain and the gut is a marvelous balance of stress, digestion, immunity, and even mood. We experience stressful situations every day, and over time those stresses can take their toll. The overall health of the gut is probably one of the single most important issues we address in an active practice because it influences far more than digestion alone.

The Gut-Brain Axis is truly a two-way street, sending and receiving information in both directions. One of the primary communication pathways is the Vagus nerve, the longest cranial nerve in the body. It continually carries messages from the digestive tract to the brain and from the brain back to the digestive organs. In fact, researchers estimate that a majority of the nerve fibers within the Vagus nerve carry information from the gut to the brain rather than the other way around. This means your digestive system is constantly influencing how you think, feel, and respond.

Even more fascinating is the role of the gut microbiome—the trillions of bacteria and other microorganisms that live within the intestines. These microbes help digest food, produce vitamins, regulate immune function, and manufacture or influence many of the body’s neurotransmitters and signaling molecules. Although serotonin is widely known as the “feel-good” neurotransmitter, approximately 90% of the body’s serotonin is produced in the digestive tract, where it helps regulate intestinal function while also participating in gut-brain communication. The microbiome also affects the production and activity of other important brain chemicals, including GABA and dopamine, which help influence mood, focus, and emotional resilience.

When we’re upset by something happening right now, the response is quick and automatic. The brain signals the release of stress hormones that can slow digestion, tighten the stomach, alter intestinal motility, and redirect blood flow away from the digestive system. But when the stimulus comes from a stored brain pattern—a Subconscious Emotional Memory Override (S.E.M.O.)—the same physiological response can occur without conscious awareness. It’s automatic, but often more insidious. It’s like it sneaks up on us and grabs us…in the gut.

Researchers have also discovered that chronic stress can change the composition of the gut microbiome, weaken the integrity of the intestinal barrier, and increase inflammatory signaling throughout the body. This may help explain why ongoing emotional stress is frequently associated with digestive discomfort, fatigue, lowered resilience, and changes in mood. Likewise, an unhealthy gut can send distress signals back to the brain, creating a cycle in which emotional stress and digestive symptoms reinforce one another.

B.E.S.T. is geared not only to address these stress responses but also to update the subconscious memory patterns associated with them. Real or imagined, the body’s response through the Gut-Brain Axis is remarkably automatic and predictable.

We adapt to stress by changing activity within the gut, or we adapt our thinking in response to signals coming from the gut. Sometimes this becomes a positive feedback loop—a win/win situation. More often, unresolved stress creates a lose/lose response that may manifest as worry, fear, an upset stomach, constipation, loose stool, bloating, or anxiety.

Within the Morter HealthSystem, these automatic emotional response patterns are understood to involve the limbic centers of the brain, where emotional memories strongly influence physiology. This is the essence of an S.E.M.O.—a learned subconscious pattern that continues to produce familiar reactions long after the original event has passed.

The encouraging news is that the nervous system is capable of change. Neuroscience has demonstrated that the brain possesses neuroplasticity—the lifelong ability to reorganize neural pathways in response to new experiences. As patterns change, physiological responses can change as well. From the B.E.S.T. perspective, these stored response patterns are not permanent. They can be recognized, updated, repurposed, and replaced so they better reflect present-day reality rather than yesterday’s experiences.

When the brain and gut communicate in harmony, digestion improves, resilience increases, and the body is better equipped to heal, adapt, and thrive. The Gut-Brain Axis reminds us that true health is never just about the stomach or just about the mind—it is about the continual conversation between the two.