Irritable bowel syndrome affects 10–15% of the global population, disproportionately women. It is one of the most common reasons people visit their GP, and one of the most frustrating to treat — because conventional medicine looks for structural damage in a condition that is, at its core, a disorder of signalling.
The gut was the first brain
The gut contains more than 500 million neurons — more than the spinal cord. It communicates bidirectionally with the brain via the vagus nerve, and produces roughly 90% of the body’s serotonin. The enteric nervous system is phylogenetically ancient, appearing long before the centralised brain of vertebrates. The gut was, evolutionarily speaking, a nervous system before there was a head.
IBS is not a problem with the gut’s structure. It is a problem with its signalling. The gut is hypersensitive — overresponding to normal stimuli. This hypersensitivity is often rooted in disrupted vagal tone, altered gut microbiome composition, low-grade chronic inflammation, and a chronically activated stress-response system. All are evolutionary mismatches.
Why the stress connection makes evolutionary sense
In evolutionary terms, the gut was designed to shut down during acute stress — digestion is energetically expensive when running from a predator. Chronic low-grade stress achieves the same shutdown, but persistently. Gut motility becomes dysregulated, the microbiome shifts, and intestinal permeability increases. The result is a system in a constant state of low-level alarm.
What this means at OQ
At OQ, IBS is approached through the autonomic nervous system and the visceral mechanical environment. Osteopathic visceral and cranial techniques can help restore vagal tone, reduce diaphragmatic restriction, and improve the mechanical relationship between abdominal organs — creating conditions in which the gut’s own nervous system can begin to self-regulate more effectively.
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