The cause of IBS is unknown, nevertheless, a significant amount of information has been acquired about this disorder during numerous decades of research. In particular:
- The two underlying mechanisms that cause or significantly contribute to the symptoms of IBS are understood to be altered intestinal motility (abnormal bowel function) and visceral hypersensitivity (increased gut sensitivity). (Abstract links below.)
- Links to anxiety & depression have been noted. (Abstract links below.)
- Irritable bowel syndrome, anxiety, and depression: what are the links?
- Anxiety but not depression determines health care-seeking behaviour in Chinese patients with dyspepsia and irritable bowel syndrome: a population-based study.
- Irritable bowel syndrome may follow a gut infection, this is known as post-infectious IBS (PI-IBS). (Abstract links below.)
- Altered colonic microflora, unusual gut fermentation and irregular breath testing are found in a significant proportion of IBS patients. (Abstract links below.)
- Abnormal colonic fermentation in irritable bowel syndrome.
- Analysis of the Fecal Microbiota of Irritable Bowel Syndrome Patients and Healthy Controls with Real-Time PCR.
- Normalization of lactulose breath testing correlates with symptom improvement in irritable bowel syndrome. a double-blind, randomized, placebo-controlled study.
- Proboitics (friendly bacteria) may alleviate IBS symptoms. (Abstract links below.)
- A probiotic mixture alleviates symptoms in irritable bowel syndrome patients: a controlled 6-month intervention.
- Intestinal microflora and oral bacteriotherapy in irritable bowel syndrome.
- Significant antibiotic use is associated with the onset of IBS. (Abstract links below.)
- Antibiotic use, childhood affluence and irritable bowel syndrome (IBS).
- Antibiotics increase functional abdominal symptoms.
- Carbohydrate malabsorption/intolerance appears to be common among IBS sufferers. (Abstract links below.)
- Sugar malabsorption in functional bowel disease: clinical implications.
- Functional bowel disease: malabsorption and abdominal distress after ingestion of fructose, sorbitol, and fructose-sorbitol mixtures.
- Symptom provocation in irritable bowel syndrome. Effects of differing doses of fructose-sorbitol.
- Low-grade intestinal inflammation has been noted . (Abstract links below.)
- Terminal ileal mucosal mast cells in irritable bowel syndrome.
- Full-thickness biopsy of the jejunum reveals inflammation and enteric neuropathy in irritable bowel syndrome.
- IBS symptom variability and instability. (Abstract links below.)
- A prospective assessment of bowel habit in irritable bowel syndrome in women.
- Clinical patterns over time in irritable bowel syndrome.
- Convincing links between IBS and inflamed bowel disease especially Crohn’s. (Abstract links below.)
Although the cause of IBS is unknown, it’s speculated that the disorder may originate from a dysfunction of the so-called ‘brain-gut axis’, which, somehow, may lead to increased gut sensitivity and abnormal function. However, this hypothesis provides no obvious explanation for other, important areas of IBS research, including low-grade intestinal inflammation, carbohydrate malabsorption/intolerance, links between IBS and IBD, abnormal intestinal-flora and why probiotics may alleviate symptoms.






