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Canadian Journal of Gastroenterology
Volume 8, Issue 6, Pages 389-393

Fructose and/or Sorbitol Intolerance in a Subgroup of Lactose Intolerant Patients

SR Mishkin, L Sablauskas, and S Mishkin

Division of Gastroenterology, Royal Victoria Hospital, Department of Medicine, McGill University, Montreal, Quebec, Canada

Received 6 January 1994; Accepted 19 May 1994

Copyright © 1994 Hindawi Publishing Corporation. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


The diagnosis and treatment of lactose intolerance often does not resolve all the symptoms of postcibal bloating and flatulence. Included in this study were 104 lactose intolerant patients (71 female, 33 male) who complained of residual postcibal discomfort in spite of adherence to and benefit from appropriate measures for their documented lactose intolerance (at least 20 ppm H2 after 25 g lactose as well as appropriate symptomatic discomfort). Clinical characteristics common to this group included: symptomatic diarrhea (12.5%), history of foreign travel (5.8%), endoscopic and pathological evidence of gastritis and helicobacter infection (19.2 and 8.7%, respectively), nonspecific abnormalities of small bowel follow-through (15.4%), Crohn’s disease (8.7%) and colonic cliverticulosis (14.4%). Intolerance co fructose (at least 10 ppm H2 after 25 g fructose plus appropriate symptoms) or sorbitol (at least 10 ppm H2 after 5 g sorbitol plus appropriate symptoms) was documented in 17.3 and 18.3%, respectively. Intolerance to both fructose and sorbicol (administered as separate challenges), more than twice as common as intolerance to either one alone, occurred in 41.4% and was independent of sex. In conclusion, additional carbohydrate intolerances contribute to postcibal discomfort in more than 75% of lactose intolerant patients who remain symptomatic in spite of adherence to appropriate measures for this condition. While 62% of all patients had benefited significantly (greater than 50%) from appropriate dietary measures and enzyme replacement for lactose intolerance, only 40% of those who were also fructose intolerant and 47% who were sorbitol intolerant benefited (greater than 50%) from appropriate dietary measures (no enzyme replacement yet available) for intolerance to these sugars.