The Gut Microbiome in Health and in Disease

Andrew B. Shreiner; John Y. Kao; Vincent B. Young


Curr Opin Gastroenterol. 2015;31(1):69-75. 

In This Article

Irritable Bowel Disease and the Microbiota–gut–brain Axis

A role for the microbiota in irritable bowel syndrome (IBS) is suspected, though unproven, and therapies that alter the microbiota, including dietary changes, probiotics, and antibiotics, have shown encouraging, though inconsistent, results.[32] In two reports describing the results of dietary intervention with a low-fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAP) diet consisting of restricted intake of certain fermentable substrates compared to a typical Australian diet in a small number of Australian patients with IBS, the low-FODMAP diet improved symptoms and resulted in changes in the gut microbiota, including reductions in putatively healthy bacteria, such as those in butyrate-producing Clostridium cluster XIVa.[33,34] One proposed pathway involved in IBS is through a microbiota–gut–brain axis, linking changes in the gut to symptom perception in the central nervous system. An interesting recent report demonstrated that the intake of a probiotic-rich fermented milk product resulted in alterations in brain activity in response to visual emotional stimuli as measured by functional MRI as compared to the intake of a control product.[35] The study of IBS is challenging because of the lack of specific diagnostic tests and the possibility of heterogeneous etiologies. There may be a subset of patients in whom microbiota changes are particularly important and for whom therapies to affect microbiota composition and function may be beneficial.