title: Relationship between lactose digestion, gastrointestinal transit time and symptoms in lactose malabsorbers after dairy consumption.
abstract: BACKGROUND
  The relationship of symptoms with objective measurements, as well as some of the mechanisms involved in lactose tolerance after yoghurt consumption, remain unclear.
  
  
  METHODS
  The trial had a double-blind design in which 22 lactose malabsorbers received 25 g daily lactose in fresh (living bacteria > 108 cfu/g) yoghurt or heated (< 102 cfu/g) yoghurt for 15 days, followed by a cross-over (15 days) after a wash-out period (14 days). The lactose digestion was determined by the breath H2 test, the gastric emptying (GE) with a 13C-acetate breath test and the revealed transit time (OCTT) by 15N-lactose-ureide test. Subjects reported their gastrointestinal symptoms (GIS) in a validated questionnaire.
  
  
  RESULTS
  Breath H2 test indicated more effective lactose digestion after fresh yoghurt intake. The OCTT was shorter after heated yoghurt ingestion as compared with the fresh. There was lower severity of GIS (P < 0.05) after fresh yoghurt intake, and this showed an inverse correlation with OCTT (P < 0.05).
  
  
  CONCLUSIONS
  Delayed orocoecal transit time was associated with fewer gastrointestinal symptoms. The improved lactose digestion and tolerance of fresh yoghurt should be mainly attributed to the presence of living bacteria.
authors: Department of Physiology and Nutrition, University of Navarra, Pamplona, Spain.
authors: I
authors: I
authors: Labayen
authors: L
authors: L
authors: Forga
authors: A
authors: A
authors: González
authors: I
authors: I
authors: Lenoir-Wijnkoop
authors: R
authors: R
authors: Nutr
authors: J A
authors: JA
authors: Martínez
mesh_terms: D000328:Adult; D001944:Breath Tests; D002247:Carbon Isotopes; D018592:Cross-Over Studies; D004032:Diet; D004311:Double-Blind Method; D005260:Female; D005772:Gastrointestinal Transit / Q000502:physiology*; D006801:Humans; D007785:Lactose / Q000378:metabolism*; D007787:Lactose Intolerance / Q000503:physiopathology*; D008297:Male; D012720:Severity of Illness Index; D013696:Temperature; D015014:Yogurt
chemical_list: D002247:Carbon Isotopes; D007785:Lactose