title: Carbohydrate intolerance in patients with self-reported food hypersensitivity: comparison of lactulose and glucose.
abstract: OBJECTIVE
  Malabsorption of low-digestible carbohydrates is physiological, but poorly tolerated in some patients. We investigated symptom anticipation and microbial fermentation as possible mechanisms of carbohydrate intolerance in patients with self-reported food hypersensitivity.
  
  
  METHODS
  In a randomized, double-blind, cross-over study, 27 consecutive patients with unexplained, self-reported food hypersensitivity were given 10 g lactulose and 10 g glucose (placebo). Symptoms and pulmonary excretion of hydrogen and methane were assessed. Short-chain fatty acids (SCFAs), lactate and prostaglandin E(2) (PGE(2)) were analyzed in rectal dialysis fluid, and compared to dialysates from nine healthy volunteers.
  
  
  RESULTS
  Post-lactulose symptom scores were correlated with habitual symptom scores (r = 0.6, p = 0.001), significantly higher than post-glucose symptom scores (p = 0.01) and significantly higher in patients than controls (p = 0.0007). Levels of SCFAs, lactate and PGE(2) in rectal dialysates were not significantly different after lactulose and glucose, or between patients and controls. Hydrogen excretion was not correlated with symptom scores.
  
  
  CONCLUSIONS
  The findings suggest that self-reported food hypersensitivity is related to microbial fermentation of malabsorbed carbohydrates and not to symptom anticipation solely. Levels of SCFAs, lactate and PGE(2) in rectal dialysates could not explain the fermentation-associated hypersensitivity.
authors.affiliation: Institute of Medicine, University of Bergen, Bergen, Norway. jorgen.valeur@med.uib.no
authors.forename: Jørgen
authors.initials: J
authors.lastname: Valeur
authors.forename: Mette Helvik
authors.initials: MH
authors.lastname: Morken
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Norin
authors.forename: Tore
authors.initials: T
authors.lastname: Midtvedt
authors.forename: Arnold
authors.initials: A
authors.lastname: Berstad
mesh_terms: D000293:Adolescent; D000328:Adult; D001944:Breath Tests / Q000379:methods; D002241:Carbohydrates / Q000009:adverse effects; D018592:Cross-Over Studies; D015232:Dinoprostone / Q000032:analysis; D004311:Double-Blind Method; D005232:Fatty Acids, Volatile / Q000032:analysis; D005243:Feces / Q000737:chemistry; D005260:Female; D005512:Food Hypersensitivity / Q000175:diagnosis / Q000378:metabolism*; D005947:Glucose / Q000008:administration & dosage / Q000009:adverse effects*; D006801:Humans; D006859:Hydrogen / Q000032:analysis; D019344:Lactic Acid / Q000032:analysis; D007792:Lactulose / Q000008:administration & dosage / Q000009:adverse effects*; D008286:Malabsorption Syndromes / Q000175:diagnosis / Q000378:metabolism*; D008297:Male; D008697:Methane / Q000032:analysis; D008875:Middle Aged; D012720:Severity of Illness Index
chemical_list: D002241:Carbohydrates; D005232:Fatty Acids, Volatile; D019344:Lactic Acid; D007792:Lactulose; D006859:Hydrogen; D005947:Glucose; D015232:Dinoprostone; D008697:Methane