The Ecological Role of Yeasts in the Human Gut

Irritable bowel syndrome (IBS) and inflammatory bowel disease (IBD) (categorised into Crohn's disease (CD) and ulcerative colitis (UC)) are chronic gut disorders with debilitating symptoms that profoundly impact quality of life, healthcare systems and the economy through lost work days. IBS is common with a prevalence of up to 22%, whereas IBD has a prevalence of 0.3% for CD and 0.5% for UC in Europe. Despite a suggested immunological and genetic aspect of IBD, the causes of IBS and IBD are unknown, however, both have been linked to yeasts in the gut. Due to their lower abundance (constituting only around 0.1% of the total microorganisms in the gut) yeasts have been less studied than bacteria. More recently, significantly altered diversity and composition of yeasts have been identified in IBS and IBD but further investigation is required to fully develop the role of yeasts in the gut. This observational study will assess yeasts and their function in the gut, comparing diseased subjects with healthy controls. The overall aim is to determine if yeasts could be targeted as a potential therapeutic for IBS and IBD to provide relief to sufferers as well as reducing the burden on healthcare systems.