The dietary fibre psyllium reduces inulin-related gas production in patients with IBS but does not directly inhibit fermentation, according to a new in vivo and in vitro study.

Despite the apparent clinical benefits of a low-fermentable oligosaccharide, disaccharide, mono-saccharide and polyols (FODMAP) diet in IBS, it inevitably also reduces intake of substances which act as prebiotics, leading to a reduction in beneficial gut bacteria, which has its own potential negative consequences. Alternative approaches to control colonic fermentation in IBS are therefore being pursued.

Psyllium, a form of a fiber made from the husks of the Plantago ovata seeds, has been found to improve symptoms in IBS although the exact mechanisms are unclear.

The current study used MRI to test the hypothesis that psyllium can reduce the increase in colonic gas induced in IBS by inulin.

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