Probiotics are microorganisms that supplement the gut's natural bacteria, helping to "balance" intestinal flora. There is a growing interest in the relationship between gut microbiota and human health and disease. Alterations in intestinal microbiota (employing probiotics, prebiotics, synbiotics and antibiotics) are used in attempts to treat gastrointestinal disorders including IBS. Probiotics are effective in the treatment of IBS symptoms, but the most effective species are unclear.The composition of gut microbiota in patients with IBS is different to that in healthy people and this fact underpins the use of probiotics in IBS treatment. However, although treatment with multispecies probiotics rather than a single organism relieve some IBS symptoms, it is not clear which organisms induce the change in intestinal microbiota.

 

Results

The proportion of patients whose IBS symptoms were substantially relieved at week 4 was significantly higher in the probiotics group than in the placebo group: 68.0% (17/25) versus 37.5% (9/24) (P < 0.05). Secondary end-points such as improvement in abdominal pain/discomfort and bloating occurred in the probiotics group but not in the placebo group. Fecal analysis revealed that B. lactis, L. rhamnosus, and S. thermophilus had increased significantly in the probiotics group after 4 weeks and that B. lactis had increased in the placebo group.