The gut has its own nervous system and communicates continuously with the brain through the vagus nerve, immune signalling and microbial metabolites. This is why stress produces genuine changes in gut motility and sensitivity, and why gut symptoms in turn affect mood and sleep.
A second nervous system
The enteric nervous system contains several hundred million neurons and can operate independently of the brain. It is connected to the brain by the vagus nerve, and the traffic runs in both directions — with considerably more of it travelling from gut to brain than the other way.
Most of the body’s serotonin is produced in the gut. Gut bacteria produce neuroactive compounds, including short-chain fatty acids that influence the brain. This is a physical system, not a metaphor.
Is this what is happening to you?The two-minute check further down asks four questions and shows the result immediately. No email, no call.
Take the 2-minute checkWhy stress changes digestion
Under stress the body redirects blood away from the digestive tract, alters motility and increases the sensitivity of gut nerves. Something that would normally pass unnoticed registers as pain.
This is the mechanism behind irritable bowel syndrome, and it is why the condition is real, physical and measurable despite producing a normal colonoscopy. Being told that nothing is wrong is one of the more unhelpful experiences in medicine, and it is not the same as being told there is nothing to treat.
- Altered motility, producing either constipation or urgency
- Heightened visceral sensitivity, so normal gas registers as pain
- Changed acid secretion and stomach emptying
- Shifts in the gut barrier and in microbial composition
2-minute check
What is going on with your digestion?
Four questions, answered in about a minute.
When does discomfort appear?
Any bloating through the day?
Has your bowel habit changed?
How often do you take an antacid or laxative?
This sounds occasional rather than established
Meal timing, fibre and fluid usually settle it.
A pattern is forming
Regular antacid or laxative use is worth reviewing — it manages the symptom rather than the cause.
This fits an established pattern
Worth proper assessment rather than continued self-medication, particularly if sleep is affected.
This check is an indication, not a diagnosis. It does not replace medical advice.
The loop runs both ways
Gut inflammation and microbial imbalance affect mood and sleep through the same pathways. Someone with persistent digestive symptoms who becomes anxious about eating is not being irrational; they are experiencing the second half of a loop.
Treating only one end of it tends to produce partial results. This is why approaches combining dietary change with sleep and stress work do better than either on its own.
What is worth doing
On the gut side: regular meal timing, adequate fibre introduced gradually, fermented foods for live cultures, and identification of genuine individual triggers rather than adoption of a long general list.
On the nervous system side: sleep regularity, which affects gut motility directly; slow breathing before meals, which shifts the balance towards the rest-and-digest state; and physical activity, which improves motility and mood together.
Where anxiety is significant, it deserves treatment in its own right. Nutrition supports that work; it does not substitute for it.
In short
Questions we are asked
Is IBS a real condition?
Yes. It involves measurable changes in motility, gut sensitivity and the microbiome. A normal colonoscopy means structural disease has been excluded, not that nothing is happening.
Will probiotics help?
Evidence varies by strain and by condition, and the honest answer is that the research is uneven. Fermented foods are a reasonable and inexpensive place to start before buying capsules.
Reading about it is the easy part.The assessment turns this into your own numbers — free, with a free first consultation, and no figure quoted that we cannot substantiate.
Start my free assessmentConditions this relates to
Recipes that put this into practice
Low-trigger vegetable khichdi
Deliberately plain. What to eat when your gut is having a bad week.
See the recipe →Fennel and coriander infusion
Saunf after a meal, made properly — steeped, not boiled.
See the recipe →Overnight soaked figs and prunes
The most reliable thing we recommend for constipation, and the one instruction people skip.
See the recipe →Related reading
Acidity is usually not about too much acid
The acid is meant to be there. The problem is where it ends up.
Read →Why adding fibre sometimes makes constipation worse
The advice is right. The way it is usually followed is not.
Read →Migraine triggers: what is real and what is coincidence
The food you blame may be a symptom of the attack, not its cause.
Read →References
- Indian Society of Gastroenterology — consensus on irritable bowel syndrome.
- Rome Foundation — Rome IV criteria for functional gastrointestinal disorders.
- [Further references to be completed by the medical review panel.]
This article is general health information, written by a clinical nutritionist and reviewed by a doctor. It is not a diagnosis and it does not replace advice from your own clinician. Never change prescribed medication on the basis of what you read here.