title: Irritable bowel syndrome: is the search for lactose intolerance justified?
abstract: OBJECTIVE
  To determine if confirmation of hypolactasia offers any benefit to the dietary treatment of patients with irritable bowel syndrome (IBS).
  
  
  METHODS
  One hundred and twenty-two consecutive IBS patients (37 male, 85 female) were given lactose hydrogen breath tests (LHBT). Those with positive LHBT followed a low lactose diet for 3 weeks. Those improving on the diet were given double-blind, placebo-controlled challenges (DBPCC) with 5 g, 10 g and 15 g of lactose and a placebo, to confirm lactose intolerance. Those who did not respond to the low lactose diet followed either an exclusion or low fibre diet. Symptoms scores were kept prior to the LHBT, 8 h post-LHBT and daily whilst following any dietary change. Patients with negative LHBT returned to clinic and subsequent dietary interventions were recorded.
  
  
  RESULTS
  LHBT was positive in 33/122 (27%) IBS patients. Syrr otom scores prior to LHBT were not significantly different between the two groups, but after LHBT the symptoms in the positive group were significantly worse. Twenty-three patients followed a low-lactose diet of which only nine (39%) improved. Six who did not improve followed an exclusion diet, three improved and all were intolerant of milk. Three tried a low fibre diet with two improving. DBPCC were inconclusive. In the negative LHBT group 35 agreed to try a diet and 24 improved (69%). Eight were intolerant of cow's milk.
  
  
  CONCLUSIONS
  Use of a low lactose diet was disappointing in IBS patients with lactose malabsorption. Food intolerance was demonstrated in IBS patients with positive or negative LHBT and milk was identified as a problem in both groups. DBPCC were inconclusive. There appears to be little advantage in trying to separate patients who malabsorb lactose from others with IBS.
authors: Department of Gastroenterology, Addenbrooke's Hospital, Cambridge, UK.
authors: T J
authors: TJ
authors: Parker
authors: J T
authors: JT
authors: Woolner
authors: A T
authors: AT
authors: Prevost
authors: Q
authors: Q
authors: Tuffnell
authors: M
authors: M
authors: Shorthouse
authors: J O
authors: JO
authors: Hunter
mesh_terms: D000328:Adult; D000368:Aged; D001944:Breath Tests; D003109:Colonic Diseases, Functional / Q000150:complications* / Q000178:diet therapy*; D005260:Female; D006801:Humans; D007787:Lactose Intolerance / Q000150:complications* / Q000175:diagnosis* / Q000178:diet therapy; D008297:Male; D008875:Middle Aged