As a Clinical Nutritionist, I work with many clients who struggle with persistent digestive issues — bloating, cramping, irregular bowel habits — often with no clear diagnosis. More often than not, these symptoms point to Irritable Bowel Syndrome or IBS. But what many don’t realise is how deeply IBS is connected to the brain, not just the gut.
What Is IBS?
Irritable Bowel Syndrome is a functional gastrointestinal disorder. This means that symptoms occur without visible signs of damage or disease on standard tests. It affects roughly 1 in 10 people worldwide, and symptoms can range from:
- Abdominal pain or cramping
- Bloating
- Diarrhea, constipation, or both
- Mucus in the stool
- A feeling of incomplete evacuation
It can be challenging working out if you have IBS or not as these symptoms overlap with other gastrointestinal disorders.
Causes of IBS: A Multifactorial Puzzle
There isn’t one clear cause of IBS. Instead, it results from a combination of factors, including:
- Altered gut motility (how fast or slow food moves through the intestines)
- Visceral hypersensitivity (increased sensitivity to pain in the gut)
- Dysbiosis (imbalances in the gut microbiome)
- Small intestinal bacterial overgrowth (SIBO)
- Food sensitivities
- Infections (such as post-infectious IBS after food poisoning)
But one of the biggest, often overlooked drivers is stress — specifically, how the brain and gut communicate.
The Gut-Brain Connection: Why IBS Isn’t ‘All in Your Head’
The gut and brain are in constant conversation via the gut-brain axis — a two-way communication system that links the emotional and cognitive centres of the brain with the gut. This system involves:
- The vagus nerve
- The enteric nervous system (often called our “second brain”)
- Gut microbes and the metabolites they produce
- Hormones and neurotransmitters, like serotonin and cortisol
When we experience chronic stress, this communication gets disrupted. Stress can:
- Increase gut sensitivity (making normal sensations feel painful)
- Alter gut motility (leading to diarrhea or constipation)
- Change gut microbiota composition
- Disrupt digestion and nutrient absorption
This is why managing IBS must involve not just what you eat but how you manage stress.
Stress: The IBS Trigger We Can’t Ignore
Research shows that people with IBS often have a history of chronic stress, trauma, or anxiety. While stress doesn’t cause IBS, it can exacerbate and sustain symptoms.
When we’re in fight-or-flight mode:
- Blood flow is diverted away from digestion
- Stomach acid and enzyme production slows down
- Gut motility changes
- Inflammation can increase
This creates the perfect storm for IBS symptoms to flare.
What Can You Do?
Getting to the root cause of IBS is essential. A ‘band-aid’ approach means that you will continue to suffer and continue with the anxiety you have around food.
- Nutrition: Identify and remove trigger foods, support gut lining and feed beneficial microbes with a whole food diet.
- Stress management and self-care: Incorporate daily nervous system support — breathwork, meditation, massage, sleep hygiene. Choose something that you enjoy and where you feel relaxed and calm.If you would like more tips on how to reduce stress, check out my blog ‘Top Stress Hacks For A Happier Gut’
- Gut-brain healing: Practices like gut-directed hypnotherapy, vagus nerve stimulation and working with a practitioner to address past trauma can help. The Nerva app is an evidence-based gut-directed hypnotherapy app which helps you better manage your symptoms.
- Personalised care: Work with a qualified practitioner to address underlying gut infections, SIBO or dysbiosis.
IBS is not “just in your head,” but your head and your gut are definitely involved. A comprehensive, gut-brain-focused approach can make all the difference. If you’ve been struggling with IBS and feel like you’ve tried everything, it may be time to look beyond just your diet and consider how your stress and nervous system health are playing a role.
If you’ve been struggling with your IBS for a while and need help, why not book in with Sal for a free 20 min Zoom or phone call. Alternatively, find out about the Mind Your Gut program here.