1. Irritable bowel syndrome - an enterometabolic disorder?
Jørgen Valeur
Institute of Medicine
University of Bergen
Norway

2. = Irritable bowel syndrome
IBS
= Irritable bowel syndrome
Psychopathology?
Stress?
Altered
brain-gut axis?
Disturbed
microflora?
Hormonal
dysfunction?
Inflammation?
Atopy?
Enteric
neuropathy?

3. – Why do we have colon? Ruminant (sheep) Monogastric herbivore (pony)
Omnivore
(human)
Carnivore
(dog)
Valeur J, Berstad A. Tidsskr Nor Legeforen 2008; 128:

4. – What is fermented in colon?
Mainly carbohydrates
Complex carbohydrates
Dietary fiber
Soluble
(Insoluble)
Resistant starch
FODMAP*
Fermentable
Oligosaccharides
Disaccharides
Monosaccharides
And
Polyols
~ g/day
* term registered by Shepherd & Gibson

5. Simren M et al. Digestion 2001; 63: 108-15

6. Clinical gastroenterology and hepatology, 2009

7. In IBS Low digestible carbohydrates: Tolerability in health
Grabitske & Slavin, 2009

8. Hypothesis: IBS is a fermentation disorder
Lancet 1991; 338: 495-6

9. British journal of Nutrition, 2002
Madden JAJ, Hunter JO.
British journal of Nutrition, 2002

10. Deutsches Arch f klin Med 1901; LXIX: 570-605

11. Quarterly Journal of Medicine, 1931

12. Lactulose Nonabsorbable, but fermentable synthetic disaccharide
Lactulose challenge: Model for carbohydrate malabsorption
10 g lactulose causes abdominal symptoms (pain, gas, borborygmia, diarrhoea) in IBS patients, but not in healthy subjects
Symptoms resemble habitual symptoms
Morken MH et al. Eur J Gastroenterol Hepatol 2007; 19:
Morken MH et al. Scand J Gastroenterol 2008; 43: 141-5

13. Symptoms following lactulose ingestion
negative expectations or
hypersensitivity to fermentation ?

14. Study Randomized Double-blinded Placebo-controlled (10 g glucose)

15. Design

20. Rectal dialysis

22. Conclusions
IBS patients seem to be hypersensitive to intestinal fermentation
Lactulose replicates habitual symptoms, both qualitatively and quantitatively
Neither gas production nor altered rectal fermentation could fully account for symptom generation

23. Hypersensitivity to fermentation
Normal perception of abnormal fermentation or
abnormal perception of normal fermentation ?

24. Modified from Simrén (2009)
Speculations
Modified from Simrén (2009)