Irritable bowel syndrome (IBS) is one of the most common gastrointestinal disorders, affecting approximately 10% of the population worldwide, and about 15% of the Western population.
Women are affected more frequently, in particular young women under 50 years of age (Lovell & Ford 2012). IBS can be a debilitating condition, severely affecting quality of life, comparable to the quality of life of someone with diabetes or depression (Suares et al. 2011). The symptoms of IBS are diverse and the exact causes remain unclear, but in most cases they are multifactorial. Many studies have associated changes in the intestinal microbiota with IBS pathophysiology (reviewed by Rajilic-Stojanovic et al. 2015), often characterised by:
• Reduced diversity of intestinal bacteria
• Increased relative proportion of Firmicutes, especially Clostridium cluster XIVa and Ruminococcaceae
• Decreased relative proportion of Bacteroidetes.
In addition, there is an increased risk of developing IBS after bacterial gastroenteritis or antibiotic therapy, further substantiating the gut microbiota’s involvement in IBS.
A recent meta-analysis shows that probiotics can be effective in IBS. In particular, single strain probiotics and a short treatment period improved overall symptoms and the quality of life more effectively than placebo (Zhang et al. 2016). The growing body of evidence has led to guidelines advising that should a patient choose to try a probiotic product they should take the probiotic for at least four weeks and monitor symptoms. (Layer at al. 2009, McKenzie et al. 2016, NICE Clinical Guideline CG61 2008).
Study: IBS & Small Intestinal Bacterial Overgrowth
Effects on intestinal fermentation patterns in patients with irritable bowel syndrome - Barrett et al. (2008) World J Gastroenterol 14:5020-5024
Methods: In an uncontrolled, proof-of-concept study, eighteen subjects with IBS (Rome II criteria) and positive for ERBHAL (early rise in breath hydrogen after lactulose) consumed a daily fermented milk drink containing L. casei Shirota before breakfast for six weeks and kept a daily symptom diary, after which the ERBHAL test was repeated.
Results: ERBHAL was reversed in nine of the 14 patients who completed the study (64%). Assessment of all the subjects showed that the probiotic intervention increased the median time to breath hydrogen rising following lactulose ingestion from 45 min to 75 min (P = 0.03).