IBS & the Nervous System: Why Calming Your Gut Starts with Calming Your Brain
If your gut flares up every time life gets stressful, you’re not alone—and you’re not imagining it.
Many people living with IBS are told to change their diet, avoid trigger foods, take medication, or try low-FODMAP plans. But what’s often missing from the conversation is one of the most important root causes of it all: the nervous system.
The truth is, your digestive system doesn’t work in isolation. It’s in constant communication with your brain through what’s known as the gut-brain axis. When you’re under stress (mentally, emotionally, or physically), your brain sends signals to the gut that can disrupt digestion, weaken the gut lining, and trigger inflammation.
This is why so many people feel like they’re doing “everything right”—eating clean, taking supplements, following protocols—and still can’t get consistent relief. Because if your nervous system feels unsafe or overstimulated, your gut simply can’t function optimally.
In this blog, we’ll break down how your gut and brain communicate, what happens to digestion under stress, how the vagus nerve influences IBS, and how to start calming your gut by supporting your nervous system.
If your gut symptoms worsen when your life gets hectic—this one’s for you.
How Stress Affects Digestion
Ever noticed how your digestion changes when you’re anxious, overwhelmed, or under pressure? That’s not just in your head—it’s in your nervous system.
When you’re stressed, your body shifts into sympathetic dominance, commonly known as “fight or flight.” This is a primal survival response designed to help you escape danger—not digest a meal.
The result? Your gut slows down, tightens up, and starts misfiring. Let’s break it down.
What Stress Does to the Gut (Physiologically)
Stress affects nearly every aspect of your digestive system:
Reduced stomach acid and enzymes:
Your body downregulates digestive secretions to conserve energy for “survival.” This leads to bloating, belching, acid reflux, and nutrient malabsorption.
Disrupted gut motility:
Some people experience slowed motility (leading to constipation and sluggish digestion), while others get the opposite: rapid emptying and loose stools—especially in IBS-D.
Increased gut permeability (“leaky gut”):
Stress weakens the gut lining and tight junctions, allowing undigested food particles and toxins to pass through, triggering immune activation and inflammation.
Microbiome imbalances
Chronic stress alters the composition of your gut bacteria—reducing beneficial strains, encouraging overgrowth of pathogens, and impacting mood via the gut-brain axis.
Cortisol: The Stress Hormone with a Gut Side Effect
When you’re under long-term stress, your body produces more cortisol, which suppresses immune function and alters blood flow away from your digestive tract. This contributes to:
Inflammation in the gut
Impaired repair of the gut lining
Reduced secretory IgA (your first immune defence)
Changes in appetite and cravings
If you live in a constant state of mental busyness, emotional stress, or overwork—this daily cortisol drip may be silently keeping your gut in survival mode.
Stress and IBS: The Link is Real
Research shows that people with IBS often have a more reactive nervous system, lower vagal tone, and altered gut motility in response to stress.
You might find that flares happen when:
You’re rushing meals or skipping them altogether
You’re anticipating a big event or are emotionally triggered
You’re travelling, working late, or overstimulated
You haven’t had time to rest or regulate
Your gut is responding to the messages your nervous system is sending—and for many people with IBS, those messages are stuck in overdrive.
Next up, we’ll explore the vagus nerves’ specific role in gut health—and how learning to support it can restore your digestion from the top down.
The Vagus Nerve and IBS
If the gut and brain are in constant communication, then the vagus nerve is the main line between them. It’s the longest cranial nerve in the body, travelling from your brainstem down to your digestive organs—and it plays a massive role in how well (or how poorly) your gut functions.
And for those with IBS, the vagus nerve might just be the missing piece of the puzzle.
What Is the Vagus Nerve?
The vagus nerve is part of your parasympathetic nervous system, often referred to as the “rest and digest” state. When the vagus nerve is activated, your body feels safe, calm, and ready to perform functions that only happen when you’re relaxed:
Producing stomach acid and digestive enzymes
Secreting bile to break down fats
Moving food through the intestines in a rhythmic, smooth way
Activating gut motility (aka regular bowel movements)
Repairing and maintaining the gut lining
Keeping inflammation in check
Basically, your vagus nerve is the ‘on switch’ for digestion.
Vagus Nerve Dysfunction in IBS
Many people with IBS—especially those with a long history of stress, trauma, or anxiety—have what’s known as low vagal tone. This means the vagus nerve isn’t firing properly or consistently.
When vagal tone is low:
You may feel stuck in fight or flight (even at rest)
Gut motility becomes erratic or sluggish
Digestion feels tense, uncomfortable, or unpredictable
Inflammation builds up in the GI tract
You feel bloated, tight, or “nervous in the stomach” even with no food triggers
Sound familiar?
Research shows that vagal nerve dysfunction is more common in IBS patients—particularly those with IBS-D and IBS-M—and is linked to visceral hypersensitivity (heightened pain perception in the gut).
Signs of Poor Vagal Tone
Your body may already be telling you that vagal function is off. Look for these signs:
Digestive issues after eating, especially under stress
Feeling full quickly or like food “just sits there”
Difficulty taking full, deep breaths
Cold hands and feet (poor circulation)
Low heart rate variability (if tracked)
Anxiety or mental fog during gut flares
Frequent throat clearing, tight chest, or voice strain
Why Vagal Tone = Resilience for the Gut
Vagal tone is your body’s ability to shift into regulation after stress. A strong, responsive vagus nerve helps you:
Recover quickly from emotional stress
Digest food calmly and efficiently
Support balanced gut motility
Reduced the intensity and frequency of IBS flares
Feel emotionally grounded, not reactive
Think of it like this: your vagus nerve is the remote control between your brain and gut. If the signal is weak, the connection glitches. But when the signal is strong, both systems work in harmony.
Next, we’ll explore exactly how to strengthen vagal tone and support your nervous system so your gut can finally feel safe, calm, and functional again.
Tools to Support the Nervous System & Calm the Gut
You can’t heal a gut living in a survival state. That’s why when it comes to IBS, supporting your nervous system isn’t optional—it’s essential.
Here are powerful, accessible tools to help regulate your nervous system, improve vagal tone, and create an environment where your gut can finally feel safe to rest, digest, and heal.
Nervous System Regulation Practices
These simple, science-backed tools help shift your body into a parasympathetic (rest-and-digest) state and improve your vagal nerve tone over time.
Breathwork
Your breath is the fastest way to signal safety to your body.
Practices to try:
Box breathing: inhale 4, hold 4, exhale 4, hold 4
4-7-8 breathing: inhale 4, hold 7, exhale 8 (great before meals or bed)
Diaphragmatic breathing: expand the belly, not the chest
Tip: Practice before meals to turn on digestion naturally.
Cold Exposure
Brief, safe exposure to cold can stimulate the vagus nerve.
Try:
Splashing cold water on your face
Ending your shower with 30 seconds of cool water
Holding a cold compress on the back of your neck
Humming, Singing & Gargling
The vagus nerve runs through your throat—and vocal stimulation activates it.
Practice daily:
Loud gargling with water
Humming a favourite tune
Singing in the car or shower
Gentle Movement & Somatic Practices
Nature walks
Grounding exercises (barefoot on earth)
Stretching or yoga
Nervous system regulation techniques like orienting, shaking, or taping (EFT)
Even 5-10 minutes per day makes a difference
Restorative Lifestyle Habits
IBS thrives in a high-stimulation, low-recovery lifestyle. Here’s how to shift that:
Prioritize Quality Sleep
Your gut repairs itself during deep sleep. Poor sleep raises cortisol, disrupts gut bacteria, and reduces immune resilience.
Sleep hygiene tips:
Wind down with low light and no screens after 8 p.m.
Sleep in a cool, dark room
Go to bed and wake up at the same time every day (yes, even on weekends)
Avoid heavy meals or intense tasks close to bedtime
Create Daily Calm
Start the day without rushing (no phone before breakfast)
Schedule white space in your day
Eat meals slowly and mindfully (no multitasking)
Journal or brain-dump to clear mental clutter
Reduce “Mental Indigestion”
Constant stimulation (emails, screens, noise, notifications) keeps your nervous system on edge.
Try:
Digital detox hours
Less multitasking, more monotasking
Saying “no” to things that drain your bandwidth
Nutritional and Herbal Supports
Certain herbs, nutrients, and adaptogens can gently support your stress response and gut function at the same time. These should always be individualized, but common supports include:
Adaptogens (regulate the HPA axis)
Ashwagandha – calming, supports cortisol regulation
Rhodiola – energizing, great for burnout
Holy basil (tulsi) – calming, anti-inflammatory
Nervines (soothing for nervous tension)
Chamomile
Lemon balm
Passionflower
Skullcap
These can be taken as teas, tinctures, or in practitioner-grade blends
Nutrients that Nourish the Gut-Brain Axis
Magnesium glycinate or threonate – supports calm and bowel function
Omega-3s-anti-inflammatory for brain and gut
L-glutamine – helps repair gut lining, especially under stress
B-Complex – supports neurotransmitter production
Probiotics – especially strains that support the gut-brain axis (e.g., Lactobacillus plantarum, Bifidobacterium longum)
You don’t have to do everything at once. Pick 1-2 things that feel manageable and build a habit of regulation into your daily life. Just like gut healing, nervous system healing is a process—not an overnight fix.
In the next section, we’ll talk about why your gut protocol might not be working—and why these nervous system tools are the missing piece for so many people with IBS.
Why Gut Protocols Don’t Work Without Nervous System Support
If you’ve ever followed a gut-healing plan to the letter—cutting out all the right foods, taking all the right supplements, doing “everything right”—and still felt like your symptoms came roaring back during periods of stress…you’re not alone.
You Can’t Heal in Fight-or-Flight
Digestion is a parasympathetic process. That means it only works properly when your body feels safe.
When your nervous system is stuck in fight-or-flight—even if you’re calm on the outside—your body is not prioritizing digestion. Instead it:
Reduces stomach acid and enzyme output
Slows down or speeds up motility unpredictability
Makes your gut lining more permeable (aka leaky gut)
Suppresses gut repair and immune regulation
Tells your brain to stay on high alert
In this state, even the cleanest diet and best supplements won’t fully land.
Why “Perfect” Protocols Still Fail
Many IBS sufferers get caught in the cycle of:
Trying a new protocol
Feeling better temporarily
Crashing the moment life gets stressful again
This isn’t because the protocol was “wrong.” It’s because it didn’t address the missing piece: your nervous system’s capacity to regulate and recover.
When your body perceives stress—emotional, mental, physical—it reprioritizes survival. Digestion, repair, and inflammation control get bumped to the bottom of the list.
Healing = Safety + Strategy
Yes, nutrition matters.
Yes, testing can reveal important gut imbalances.
But none of it works sustainably unless your nervous system is on board.
You need more than a strict food list.
You need a regulated internal environment where your gut feels safe to heal.
That’s why any gut protocol should also include:
Breathwork and vagal tone support
Nervous system education
Somatic tools for stress processing
Gentle lifestyle adjustments that honour your body’s limits
In the next section, we’ll explore how a practitioner can help you integrate nervous system work into your gut healing journey—and finally start seeing results that last.
When to Work with a Practitioner
Supporting your nervous system alongside your gut might sound overwhelming—especially if you’ve already tried so many things. That’s where working with a qualified holistic or functional practitioner can make all the difference.
You don’t need to figure this out alone.
Signs It’s Time to Seek Support
Your gut symptoms flare every time life gets stressful
You’ve tried low-FODMAP, elimination diets, or gut supplements with little lasting improvement
You feel anxious, wired, or burnt out alongside your digestive issues
You’re exhausted from trial-and-error approaches
You intuitively know stress plays a role in your flares, but don’t know what to do about it
What Working with a Practitioner Can Look Like
In my practice, I support clients through a whole-body, root-cause lens—combining nutritional strategies, functional testing, and nervous system tools to create a personalized healing plan that fits your life.
This often includes:
In-depth health and lifestyle assessment
Functional stool testing (like the GI-Map) to assess gut infections, inflammation, enzyme function, and microbiome balance
Nutrition and supplement protocols tailored to your needs
Nervous system education and regulation strategies
Ongoing 1:1 support to adjust your plan as your body heals
Whether you’ve been dealing with IBS for years or you’re just starting to connect your gut with your stress response, it’s never too late to try a different, more compassionate approach.
In the final section, we’ll wrap up with a reminder that healing doesn’t just come from cutting things out—it comes from reconnecting with your body’s need for calm, consistency, and care.
Final Thoughts: Calm Gut, Calm Life
IBS can feel like a constant guessing game—one where food, supplements, and stress all seem to trigger symptoms without warning.
But what if your gut isn’t just sensitive—it’s responding exactly as it should to an overwhelmed, dysregulated nervous system?
When we focus solely on what to cut out of our diet and not on how to calm our system, we miss the bigger picture. Because your gut doesn’t just need fewer triggers. It needs more regulation. More rest. More safety.
The truth is:
You can’t digest in fight-or-flight.
You can’t heal without feeling safe.
And you can’t truly calm your gut…without calming your brain.
Ready to Heal from the Inside Out?
At Nicole’s Wellness, I help clients rebuild their gut health and support nervous system regulation through personalized care, advanced testing, and compassionate 1:1 guidance.
If you’re ready to stop guessing—and start healing—let’s chat.
Book your free discovery call today to explore how we can work together.
Your gut deserves peace.
Your body deserves safety.
And you deserve to feel well again—for good.