Bacterial supplementation in the irritable bowel syndrome. A randomised double-blind placebo-controlled crossover study

Abstract

Background: Symptoms of at least a subgroup of patients with irritable bowel syndrome may be associated with an alteration in gut flora. Studies on bacterial based therapy have yielded mixed results.

Aims: To determine if oral administration of the probiotic Lactobacillus casei strain GG under randomized placebo controlled conditions improves symptoms in irritable bowel syndrome patients with bloating related symptoms.

Patients: A total of 25 patients with clinically confirmed irritable bowel syndrome (Rome criteria) were enrolled in the study.

Methods: This was a randomised double-blind placebo-controlled crossover trial. Lactobacillus GG was administered as enterocoated tablets constituting a daily dosage of 10(10) colony forming units. Symptoms were assessed by daily symptom diaries and periodic questionnaires.

Results: Twenty-four patients were randomised; 19 (80%) female, mean age 40 years (range 24-60), mean duration of symptoms 4.9 years (range 0.5-18). Nineteen (80%) patients completed the study. No significant differences were found between Lactobacillus casei strain GG and placebo mean symptom scores for pain, urgency or bloating. A trend was noted, however, for a reduction in the number of unformed bowel motions on Lactobacillus casei strain GG treatment for patients with diarrhoea.

Conclusions: Lactobacillus casei strain GG alone did not significantly improve symptoms in this irritable bowel syndrome subgroup. A "diarrhoea predominant" subgroup may warrant further investigation.