Gastrointestinal transit time, gut microbiota and metabolic health:
Modulation by dietary fibers
Alterations of the gut microbiota and microbial metabolites may play an important role in the etiology of metabolic diseases such as obesity and type 2 diabetes mellitus. Key microbial metabolites are the short-chain-fatty acids (SCFA) acetate, butyrate, and propionate derived from microbial fermentation of dietary fibers. SCFA are suggested to be involved in body weight regulation and insulin sensitivity as shown in rodent studies and short-term human interventions. The passage of food through the intestine, i.e., the GI transit time plays a crucial role in postprandial nutrient metabolism and may affect gut microbiota composition. Thus, modulation of the GI transit time may impact glucose homeostasis and metabolic health. Recently, in vitro and population-wide studies suggested a bidirectional relationship between the gastrointestinal (GI) transit time and the gut microbiota composition. Using different methodological approaches, this thesis aims to provide insights into the interaction between dietary fibers, the gut microbiota and SCFA production in relation to GI transit time and metabolic health in humans.
Mattea Müller, October 24th 2019