Stress can sometimes settle in your stomach feeling like a knot. You may have had stomach pain before a big deadline, or a loss of appetite during a busy week. Maybe you鈥檙e struggling with lingering digestive discomfort that you can鈥檛 quite explain.
You鈥檙e not imagining it. Digestive issues like IBS and other gut-brain disorders affect a significant portion of the population鈥� according to a global study, it鈥檚 more than 40% of people. This highlights how closely stress and gut health are connected.
For years, many people experiencing these symptoms were told 鈥渋t鈥檚 all in your head.鈥� But science is now offering a clearer explanation. At the centre of this connection is the vagus nerve – a communication pathway between your brain and your gut that helps regulate digestion and your body鈥檚 response to stress.
When stress becomes constant, that communication can become disrupted. For some, this may show up as stomach pain, bloating, or irregular digestion.
The good news? Understanding this connection can help explain what you鈥檙e feeling鈥攁nd more importantly, what you can do to support your gut health, starting with how you eat and how you manage stress.
The vagus nerve is the primary neural pathway connecting the brain and the gastrointestinal tract, forming a central component of the gut-brain axis. Originating in the brainstem, it extends through the thoracic cavity and into the abdomen, innervating key organs including the stomach, intestines, pancreas, and liver.
As part of the autonomic nervous system, the vagus nerve enables bidirectional communication between the central nervous system and the enteric nervous system. This signalling pathway plays a critical role in maintaining gut homeostasis, influencing gut motility and secretion, as well as immune function and inflammatory responses.
Disruptions in vagal signalling, often associated with chronic stress, can impair this communication. This contributes to altered digestive function and the development or exacerbation of gastrointestinal symptoms.
The vagus nerve is the main component of the parasympathetic nervous system. When it鈥檚 functioning optimally, a state known as high vagal tone, it acts as a biological 鈥渙n鈥� switch for digestion. A healthy vagus tone can quickly shift from rest-and-digest to fight-or-flight. The vagus nerve coordinates processes like peristalsis, gastric secretion, and pancreatic functions. It allows your digestive system and your brain to stay in constant, real-time communication. It carries the signals that trigger the release of stomach acid, the secretion of digestive enzymes, and the rhythmic contractions (peristalsis) that move food through your system.
The gut and brain are in constant communication. Connected by the vagus nerve, the gut can tell the brain what鈥檚 it鈥檚 interactive with. Specialized cells, called enterochromaffin cells, found along the lining of the intestine, are connected to the vagus nerve. This allows them to send an immediate chemical message to the brain, according to new .
In addition, enterochromaffin cells can sense certain metabolites in the gut, such as short chain fatty acids (SCFAs), triggering them to produce serotonin. The amount of SCFAs in the gut is dependent on the dietary fibres in the diet, and the presence of certain probiotics. SCFAs are produced when certain probiotics degrade plant fibres (prebiotics). Serotonin produced by enterochromaffin cells can activate receptors in the vagus nerve and plays a role in digestive function and neural signalling. The serotonin produced in the gut, reaches the vagus nerve and eventually the rest of the central nervous system, impacting a variety of feelings, including hunger.
When communication along the gut-brain axis becomes dysregulated, a range of symptoms can emerge, especially those related to digestion, such as bloating, discomfort, and changes in motility.
One important factor influencing this communication is the balance of microbes in the gut. When beneficial bacteria are lacking, the production of short-chain fatty acids (SCFAs) can decline. This means enterochromaffin cells produce less serotonin. This shift can have big impacts as serotonin plays a key role in both digestive function and neural signalling, and it can activate pathways along the vagus nerve. When serotonin production is reduced, this signalling may become less efficient.
Stress is another major piece of the puzzle. Acute stress can temporarily shift the body out of a parasympathetic, 鈥渞est-and-digest鈥� state. Over time, chronic stress may reduce vagal tone, making it more difficult for the gut and brain to communicate effectively.
Because the vagus nerve plays such a central role in coordinating digestion and gut-brain signalling, disruptions in microbial balance and ongoing stress can help explain why digestive symptoms are so common鈥攁nd often persistent.
The term 鈥渧agal tone鈥� relates to working to shift the body from a “fight or flight” (sympathetic) state to a “rest and digest” (parasympathetic) state.
Stress can disrupt the excitatory-inhibitory balance within the vagus nerve. This is called low vagus tone. High vagal tone is associated with better heart rate variability (HRV), improved digestion, and a more resilient mood.
Certain foods might help support your body better when you鈥檙e experiencing stress. In particular, making a shift to a Mediterranean diet may help. A plant-focused, healthy dietary pattern, such as the Mediterranean diet enriched with dietary fiber, polyphenols, and polyunsaturated fats, is well known to positively influence the gut microbiota.
In an observational study conducted in Alberta, found adults who adhered more to a Mediterranean diet (more vegetables, fruits, nuts, legumes, whole grains, and fish) had a better diversity and number of helpful microbes in their gut. In particular, there were more beneficial fiber-degrading bacteria.
Seaweed, green tea, cocoa, and salmon are just some of the foods research suggests might be worth eating.
For those with IBS, a low-FODMAP (fermentable oligosaccharide, disaccharides monosaccharides and polyols) has been shown to significantly improve symptoms, alter the gut microbiome and increase the presence of some helpful microbes. Although, note that a low-FODMAP diet may lower levels of Bifidobacteria (present in highest volumes in the lower intestine/colon) and butyrate (a metabolite produced by probiotics that is used as an energy source).
While a well-planned plate can support a healthy gut microbiota, a holistic approach considers other lifestyle factors as well.
Eating on the run, and a Western diet aren鈥檛 really helping with nervous system regulation. When you are stressed, the body is in fight or flight mode, not rest and digest.
Even if you sit down to eat, are you scrolling on your phone or driving in a car? In our busy Canadian culture, keeps us in a sympathetic state, essentially “turning off” the vagus nerve during your meal. Without the rest, it鈥檚 hard to digest.
Cortisol-conscious eating is about more than just the menu; it鈥檚 about the environment. By practicing mindful eating – taking three deep breaths before your first bite – you can help trigger vagus nerve stimulation. This signals your body to move out of survival mode and into a state of nourishment.
involves shifting ones鈥� attention to the food you鈥檙e eating, and the act of digestion. An approach used by holistic nutritionists to support nervous system regulation, from Maryland University report mindful eating is a scientifically validated intervention to modulate the body鈥檚 stress response.
By consciously shifting the nervous system into a parasympathetic “rest-and-digest” state, mindful eating optimizes digestive function and nutrient assimilation. Since the gut is also a primary site for immune activity and hormone production, this regulation is not just a lifestyle choice that might help your gut feel better – it is a physiological cornerstone for wellness.
By understanding the gut-brain axis, it鈥檚 easier to understand the digestive symptoms so many Canadians struggle with. While the root cause of someone鈥檚 digestive distress can vary, considering the impact of the vagus nerve may be a helpful piece of the puzzle.
Are you ready to dive deeper? Learn more about the connections between our digestive health and our lifestyles to help yourself and others – explore the Natural Nutrition Diploma Program at CSNN – Canada鈥檚 leader in natural nutrition.
Become the expert your community needs.
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Wei L, Singh R, Ghoshal UC. Enterochromaffin Cells-Gut Microbiota Crosstalk: Underpinning the Symptoms, Pathogenesis, and Pharmacotherapy in Disorders of Gut-Brain Interaction. J Neurogastroenterol Motil. 2022 Jul 30;28(3):357-375. ()
Wei L, et al. Enterochromaffin Cells-Gut Microbiota Crosstalk: Underpinning the Symptoms, Pathogenesis, and Pharmacotherapy in Disorders of Gut-Brain Interaction. J Neurogastroenterol Motil. 2022 Jul 30;28(3):357-375. ()
Bonaz B, et al. The Vagus Nerve at the Interface of the Microbiota-Gut-Brain Axis. Front Neurosci. 2018 Feb 7;12:49. ()
Shah S, Mu C, Shen-Tu G, Rohmann N, Schlicht K, Laudes M, Shearer J. Influence of dietary components on the gut microbiota of middle-aged adults: the gut-Mediterranean connection. BMC Microbiol. 2025 Sep 6;25(1):573. ()
