Clinical trial: effect of active lactic acid bacteria on mucosal barrier function in patients with diarrhoea-predominant irritable bowel syndrome

Background The intestinal permeability is increased in patients with diarrhoea‐predominant irritable bowel syndrome (D‐IBS). Aim To determine the possible efficacy of lactic acid bacteria on the increased intestinal permeability in D‐IBS. Methods Treatment was employed for 4 weeks in a randomized single blind placebo controlled study with 30 D‐IBS patients. Patients were given either probiotic fermented milk (Streptococcus thermophilus, Lactobacillus bulgaricus, Lactobacillus acidophilus and Bifidobacterium Longum) or milk beverage containing no bacteria. The clinical symptoms were scored and intestinal permeability was measured by a triple sugar test before and after treatment. Results Small bowel permeability was measured as the ratio of lactulose and mannitol recovery and colonic permeability was measured as the total mass of sucralose excretion (mg). After probiotics treatment, small bowel permeability decreased significantly from 0.038 (0.024) at baseline to 0.023 (0.020) (P = 0.004), the proportion of patients with increased small bowel permeability was lower than baseline (28.6% vs. 64.3%, P = 0.023). However, colonic permeability improved neither in the probiotics group nor in the placebo group at week 4. Treatment with probiotics significantly decreased the mean global IBS scores compared with the baseline scores (9.62 ± 1.05 vs. 7.64 ± 1.24, P < 0.001). Conclusion Short‐term active lactic acid bacteria treatment for D‐IBS improved mucosal barrier function.