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.

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 the 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 (6O%), 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.

Background: Elimination diets have been used in Crohn's disease to help maintain remission following enteral feeding. However, patients often find the strict regimen difficult to follow resulting in poor compliance. This paper describes the development and evaluation of an alternative method of food re-introduction, a low-fibre, fat-limited exclusion diet or 'LOFFLEX' diet. Methods: Patients achieving remission on an elemental or peptide feed or total parenteral nutrition (TPN) chose to follow either an elimination or LOFFLEX diet. Their progress was assessed regularly and life-analysis tables used to calculate remission rates for the two groups at the end of a 2-year period. Results: In a series of 76 treatment episodes (74 patients having achieved remission on an enteral feed, two on TPN), 28 patients (37%) chose the elimination diet and 48 (63%) the LOFFLEX diet. Fourteen per cent failed to comply with the elimination diet and 8% failed to comply with the LOFFLEX diet. Eleven per cent of the elimination group and 12.5% of the LOFFLEX group relapsed immediately and were all found to have tight strictures. At 24 months, the proportion of compliant, non-strictured patients still in remission was 59% for the elimination diet and 56% for the LOFFLEX diet. Conclusion: This study suggests that the LOFFLEX diet has a similar efficacy to the elimination diet whilst being more acceptable to the patient. A randomized, prospective controlled study is now underway to further investigate these findings.

A number of recent clinical trials have promoted the use of probiotic bacteria as a treatment for irritable bowel syndrome (IBS). The recent demonstration of abnormal colonic fermentation in some patients with this condition provides an opportunity for the objective assessment of the therapeutic value of these bacteria. This study was designed to investigate the effects of Lactobacillus plantarum 299V on colonic fermentation. We conducted a double-blind, placebo-controlled, cross-over, four-week trial of Lactobacillus plantarum 299V in 12 previously untreated patients with IBS. Symptoms were assessed daily by a validated composite score and fermentation by 24-hr indirect calorimetry in a 1.4-m3 canopy followed by breath hydrogen determination for 3 hr after 20 ml of lactulose. On placebo, the median symptom score was 8.5 [6.25-11.25 interquartile range (IQR)], the median maximum rate of gas production was 0.55 ml/min (0.4-1.1 IQR), and the median hydrogen production was 189.7 ml/24 hr (118.3-291.1 IQR). On Lactobacillus plantarum 299V the median symptom score was 8 (6.75-13.5 IQR), the median maximum rate of gas production 0.92 ml/min (0.45-1.5 IQR), and the median hydrogen production 208.2 ml/24 hr (146-350.9 IQR). There was no significant difference. Breath hydrogen excretion after lactulose was reduced by the probiotic (median at 120 min, 6 ppm; placebo, 17 ppm; P = 0.019). In conclusion, Lactobacillus plantarum 299V in this study did not appear to alter colonic fermentation or improve symptoms in patients with the irritable bowel syndrome.

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