Grant: Project Grant

Humans do not digest dietary fibres, instead they are broken down (fermented) by gut microbes (bacteria and yeast), producing by-products that typically promote health. However, inflammatory bowel disease (IBD) patients can experience worsening symptoms after eating fibres for unknown reasons. Our previous work assessed several different fibres (e.g., Bfructans) and showed unfermented B-fructans can promote gut damage in specific IBD patients. This negative response was the result of loss of patient gut microbe's ability to break down B-fructan. We believe that this gut damage caused by unfermented fibres in select IBD patients may increase risk of IBD progression. In this study we aim to: (1) Evaluate how altered microbial abundance and functions in IBD impacts fermentation of select dietary fibres, and in turn can be used to predict associated human cell and patient response to these fibres. (2) Identify the human gut barrier alterations and mechanisms underlying barrier effects of the top relevant dietary fibres of interest. (3) Determine the immune cell subsets involved in immune response to the top relevant dietary fibres of interest, and mechanisms of immune cell - fibre interactions. Some fibres (e.g., B-fructans) are known prebiotics which are touted to provide health benefits in healthy individuals and some persons with IBD in remission, however our work is the first to demonstrate some IBD patients experience negative effects after consuming these fibres based on their inability to ferment fibre. It is essential we develop a proper understanding of the biological reasons behind the patient complaint that dietary fibre is not well tolerated to ensure patients do not avoid fibres altogether as fibres are essential for microbe and gut health. We hope to use our findings to support development of personalized dietary fibre guidelines for IBD patients to reduce consumption of only detrimental fibres.