Grant: Project Grant

Being overweight significantly increases risk for numerous diseases that have been linked to the microbial populations that inhabit our gastrointestinal tract. The exact role of the gut microbiota in human health appears to depend partially on diet. A diet high in fat can trigger inflammation when harmful molecules are produced by gut bacteria and taken up into the body. On the other hand, gut bacteria can ferment dietary fibre to produce short-chain fatty acids, molecules that have anti-inflammatory properties. However, we do not yet understand all the consequences of microbial fibre fermentation in the gut to healthy functioning of an individual. We also do not know how individual differences in types of bacteria that compose each person's gut microbial community influence how we can ferment different chemical types of dietary fibre. With such knowledge at hand, it would be possible to adjust an individual's diet based on the configuration of the microbes in our digestive tract. We propose to systematically investigate the interactions between fiber chemistry, the genetic make-up of the gut microbiota, and metabolic and immunological measures of health in overweight and mildly obese people. We will also look for links between different types of dietary fibre and the composition and function of each person's gut microbiota. This will allow us to test whether microbiome patterns in individuals predict the effects of the fibre. To achieve this, we will begin with an exploratory nutritional trial that compares the effects of three types of fermentable dietary fibre with the effects of non-fermentable cellulose. We will measure how fibre type and microbiota composition and function affect specific health outcomes such as reduced inflammation. This new knowledge can be used to improve dietary strategies for preventing obesity, develop strategies to modulate a person's gut microbiota for better health outcomes, and lay groundwork for personalized human nutrition.