Introduction: This preliminary study aimed to investigate the effects of the probiotic Saccharomyces boulardii on proinflammatory and anti-inflammatory cytokines in patients with diarrhea-dominant irritable bowel syndrome (IBS-D). The other objectives were to document any clinical improvement as judged by symptoms, quality of life, and histology.
Patients and methods: This was a randomized, double blind, placebo-controlled trial in which S. boulardii, 750 mg/day, or placebo was administered for 6 weeks in IBS-D patients, in addition to ispaghula husk standard treatment.
Results: Thirty-seven patients received S. boulardii and 35 patients received the placebo. As compared with placebo, the S. boulardii group showed a significant decrease in blood and tissue levels of proinflammatory cytokines interleukin-8 (IL-8) and tumor necrosis factor-α (P<0.001) and an increase in anti-inflammatory IL-10 levels, as well as an increase in the tissue IL-10/IL-12 ratio (P<0.001). No significant change in the blood and tissue levels of cytokines was found in the placebo group. Bowel-related IBS-D symptoms reported in the patients' daily diary improved in both groups. However, overall improvement in the quality of life was more marked in the S. boulardii group. Although baseline histological findings were mild, an improvement was observed in the probiotic group in the lymphocyte and neutrophil infiltrates (P=0.017 and 0.018), epithelial mitosis (P=0.003), and intraepithelial lymphocytes (P=0.024). No serious adverse events were found in either group.
Conclusion: S. boulardii with ispaghula husk was superior to placebo with ispaghula husk in improving the cytokine profile, histology, and quality of life of patients with IBS-D. These preliminary results need to be confirmed in a well-powered trial.