The following study estimates a 56% prevalence rate of small intestine bacterial overgrowth (SIBO) in patients with irritable bowel syndrome (IBS). It's been queried whether or not SIBO is a cause of IBS or whether some other factor plays a role in the development of both.
"We demonstrated for the first time reduced neuronal responses in mucosal IBS biopsies to an IBS mediator cocktail. While excitability to classical stimuli of enteric neurons was comparable to HC, the activation by the IBS-cocktail was decreased. This was very likely due to desensitization to mediators constantly released by mucosal and immune cells in the gut wall of IBS patients."
A new study indicates the potential benefit of Vitamin D for IBS (or perhaps the IBS is causing decreased vitamin D levels, but the first hypothesis appears more likely):
"The data provide evidence for widespread vitamin D insufficiency in people with IBS. There may be benefit to testing IBS patients’ vitamin D status and providing supplementation. There is a positive association between vitamin D status and quality of life measures, supporting a potential interaction between vitamin D and mental health and well-being. Clinicians may consider trialling vitamin D with patients with IBS as part of a nutritional management strategy. The results suggest a larger, adequately powered trial may be justified."
The above quote is from the Abstract for the following study: