What is IBS - Beyond the Label?

Irritable Bowel Syndrome (IBS) is a chronic functional gut–brain disorder characterized by recurring abdominal discomfort and altered bowel habits, without any structural or biochemical abnormalities detectable on standard tests.
It reflects dysregulation in the way the gut, microbiome, immune system, and nervous system communicate, rather than visible inflammation or tissue damage.

Modern research views IBS not as a single disease, but as a spectrum of gut–brain interaction disorders, where different mechanisms can dominate in different people, such as:

• Visceral hypersensitivity (the gut’s nerves are overly sensitive to normal activity)

• Altered motility (changes in how food moves through the intestines)

• Microbiota imbalance or low-grade inflammation

• Immune or histamine dysregulation, which often overlaps with conditions like Histamine Intolerance (HIT)

IBS is now classified into subtypes based on stool patterns:

• IBS-D – Diarrhoea-predominant

• IBS-C – Constipation-predominant

• IBS-M – Mixed type

Because many IBS symptoms - bloating, cramping, gas, urgency, fatigue, “brain fog” - also occur in HIT, food sensitivities, and mild gut inflammation, diagnosis is typically symptom-based and exclusionary. That means IBS is often identified only after other causes (such as coeliac disease, IBD, or enzyme deficiencies) are ruled out.

Rather than a single cause, IBS represents a multifactorial response of the gut–brain axis, shaped by diet, stress, hormones, microbiota, and immune signals - including histamine activity in many patients.