Food intolerance and the irritable bowel syndrome.

Two hundred patients (156 women) with the irritable bowel syndrome were treated with dietary exclusion for three weeks. Of the 189 who completed this study, 91 (48.2%) showed symptomatic improvement. Subsequent challenge with individual foods showed that 73 of these 91 responders were able to identify one or more food intolerances and 72 remained well on a modified diet during the follow up period (mean (SD), 14.7 (7.98) months). Of the 98 patients who showed no symptomatic improvement after three weeks of strict exclusion only three were symptomatically well at follow up (mean (SD), 12.48 (8.09 months). There was no close correlation between response and symptom complex. There was a wide range of food intolerance. The majority (50%) identified two to five foods which upset them (range 1-14). The foods most commonly incriminated were dairy products (40.7%) and grains (39.4%).