Management of patients with food intolerance in irritable bowel syndrome: the development and use of an exclusion diet

Food intolerance is an important cause of abdominal symptoms. As no objective tests are available to identify the foods concerned, diets are essential for the management of these patients. The fewer foods allowed in the diet, the greater is die chance of success. Our original studies of 182 patients between 1979 and 1982, using a diet of lamb, rice and pears, had resulted in a 67% success rate. The foods most commonly involved were wheat (60%), cows' milk (44%) and corn (44%). A less restrictive exclusion diet was developed from the results of this work, avoiding all those foods to which 20% or more of the patients had been intolerant. Of 253 patients (79%), 200 were able to complete 2 weeks on this diet and 100 (50%) were successful in controlling their symptoms. The exclusion diet was modified in the light of this experience and in a subsequent study of 129 patients, 96 (75%) were able to comply for 2 weeks, but only 39 (41%) improved on the basic diet. However, examination of the food diaries of these patients enabled the identification of less frequent food intolerances in 21 (22%) giving an overall success rate of 60 (63%). In this way, equally good results can be obtained using a nutritionally adequate exclusion diet and avoiding the difficulties of following a more rigorous elimination regime.