It is estimated that between 25 and 45 million people in the US have Irritable Bowel Syndrome or IBS. It affects people of all ages, of which 2 out of 3 are women. IBS is characterized by often conflicting gut problems, such as an alternation between diarrhea and constipation. Because it can be debilitating and is accompanied by unpredictable abdominal pain or discomfort, it can have a devastating effect on the social and professional life of the person. Although the exact cause is unknown, it is believed to be a disorder that arises from the interaction between the gut, brain, and nervous system. Stress is one of the important factors that either triggers symptoms or makes the condition worse.
A most recent analysis of IBS suggests that it may be caused or at least exacerbated by a disruption in the gut bacteria. Evidence for this has come from a number of studies that show that the composition of the gut bacteria appears to be different in sufferers of this disorder. Also inflammation appears to be present in the bowel wall of some IBS patients, which could be a result of an abnormal interaction with bacteria in the gut. A number of studies have shown that changing the composition of bacteria in the gut by probiotics can improve the symptoms of IBS. The most useful probiotics studied include Lactobacillus plantarum, Bifidobacterium bifidum, and Bifidobacterium infantis. The symptoms that are most consistently relieved by these probiotics are gas and bloating.
Kennedy, PJ et al. Irritable bowel syndrome: A microbiome-gut-brain axis disorder? World J Gastroenterol Oct 2014; 20(39): 14105–14125