Oct 18, 2025
Have you ever noticed that your stomach reacts before your thoughts catch up? Maybe it’s a tightening in your gut before a difficult conversation, nausea when you’re overwhelmed, or recurring digestive issues that seem to have no clear medical cause. These sensations are not random — they may be your body’s second brain processing stress that your conscious mind hasn’t yet acknowledged.
Hidden within the walls of your digestive tract is a vast network of over 100 million neurons — roughly the same number as in the spinal cord. This neural web, known as the enteric nervous system (ENS), is why scientists often refer to the gut as our second brain.
The ENS doesn’t just help digest food; it also communicates directly with the central nervous system through the vagus nerve — a thick information highway running between the brainstem and the gut. This communication happens in both directions, forming what’s known as the gut–brain axis.
Surprisingly, 90% of the vagus nerve’s signals travel upward, from gut to brain, not the other way around. That means your gut is often the one sending status updates to your brain, not just responding to it.
So when your stomach churns during stress, it’s not “all in your head.” It’s your gut-brain axis processing emotional and physiological signals long before your conscious mind makes sense of them.
When we experience stress, our body activates the sympathetic nervous system: the “fight or flight” branch of the autonomic nervous system. Blood flow is redirected from the digestive organs to the muscles and heart to prepare for perceived danger.
In short bursts, this system is protective. But when stress becomes chronic, digestion can remain partially “switched off,” leading to symptoms such as bloating, constipation, or IBS-like discomfort. The enteric nervous system, flooded with stress hormones like cortisol, begins misfiring signals, causing digestive distress even when no threat is present.
This is one reason why people recovering from trauma or living under ongoing stress often report gastrointestinal problems. The body, unable to process threat safely through the brain, continues to express it through the gut.
Another key player in this story is your gut microbiota, the trillions of bacteria and microorganisms living in your intestines. These microbes don’t just aid digestion; they’re active participants in emotional regulation.
Your gut microbiota produces and stores more than 30 neurotransmitters, including about 95% of your body’s serotonin, the same “feel-good” chemical targeted by many antidepressants.
When the gut microbiome is imbalanced — due to stress, diet, antibiotics, or sleep deprivation — the body’s ability to regulate mood and process emotional distress diminishes. Research now shows that gut inflammation can alter brain function, amplify anxiety, and even heighten vulnerability to depressive symptoms.
In this sense, an inflamed gut can be a mirror of an inflamed mind.
Serotonin is often thought of as the “feel-good” chemical, the neurotransmitter that helps stabilize mood, promote calm, and regulate sleep and appetite. But what’s less known is that around 95% of the body’s serotonin is produced and stored in the gut, not the brain.
This serotonin is manufactured by specialized cells in the intestinal lining (called enterochromaffin cells) and by certain gut bacteria themselves. These microbes use amino acids from food to synthesize serotonin precursors like tryptophan — and they influence how much serotonin is released into circulation.
While the serotonin in the gut doesn’t cross the blood–brain barrier directly, it communicates through the vagus nerve; the main highway between the gut and the brain. This communication affects brain regions responsible for emotion regulation, such as the amygdala (fear and threat detection) and prefrontal cortex (self-control and decision-making).
When the gut microbiome is balanced, serotonin signaling through the vagus nerve helps maintain emotional stability and resilience. You feel more regulated, grounded, and capable of managing stress.
But when the gut is inflamed or its microbial balance is disrupted (due to chronic stress, poor diet, antibiotics, or trauma), serotonin production and signaling can be altered; leading to increased irritability, anxiety, and mood instability.
In essence, the gut doesn’t just help digest your food — it helps digest your emotions.
From a trauma perspective, the gut often becomes the storage site of unprocessed emotional energy. The body senses danger or emotional overload long before the prefrontal cortex (our rational mind) has time to name or understand it.
In moments of threat, the vagus nerve transmits that sense of alarm from brain to gut and back again (a feedback loop of tension, nausea, or “gut-wrenching” sensations). Over time, if the nervous system remains dysregulated, the gut becomes hypervigilant too; misinterpreting even normal digestion as distress.
That’s why for many trauma survivors or highly stressed individuals, gastrointestinal discomfort can be an early signal of emotional suppression. The gut may literally be feeling the feelings the brain has numbed out.
The good news: both the brain and gut are capable of neuroplasticity — rewiring through consistent regulation and care.
•Therapy and body-based work: Trauma-informed therapy can help identify and name the stress that the body has been carrying. Mindfulness, EMDR, and somatic approaches help calm the vagus nerve and re-establish safety in the body.
•Nutrition and microbiome support: A diet rich in fibre, fermented foods, and plant diversity supports healthy gut bacteria, which in turn, supports emotional stability. (Since our team at VOX doesn't specialize in diet or food, we would recommend speaking to a specialist about this!)
•Breathwork and vagal tone: Practices like deep diaphragmatic breathing and grounding can directly stimulate the vagus nerve, calming both the mind and digestive system.
•Psychoeducation: Understanding that digestive issues are not “just physical” or “just psychological” allows for a more integrated approach to healing — one that honours the intelligence of both body and mind.
When your stomach speaks before your thoughts do, it may be your second brain signalling that something deeper needs your attention.
By listening to your body’s wisdom and addressing both physical and emotional health, you give yourself permission to heal on multiple levels — from the inside out.
If digestive issues or stress feel overwhelming, consider exploring the mind-body connection with trauma-informed, neuroscience-based therapy at VOX Mental Health in Barrie. Our team of registered social workers can support you in understanding how your body and mind communicate and help you develop strategies for lasting emotional and physical wellbeing.
LINKS FOR MORE:
https://www.health.harvard.edu/newsletter_article/stress-and-the-sensitive-gut#:~:text=The enteric nervous system is,can heighten anxiety and stress.
https://www.hopkinsmedicine.org/health/wellness-and-prevention/the-brain-gut-connection#:~:text=If you've ever “gone,bloating, pain and stomach upset.
https://cdhf.ca/en/ways-our-mind-and-gut-are-connected/#:~:text=90% of the neurons in,can cause anxiety and stress.&text=What we eat is one,help take care of you.
