Differential Short Chain Fatty Acid Availability Impact on Human Metabolism

Gut microbiota is being increasingly recognized as an important factor in fat distribution, insulin sensitivity and glucose and lipid metabolism. Accordingly, the intestinal microbiota could play an important role in the development of obesity and type 2 diabetes mellitus. The role of gut-derived short-chain fatty acids (SCFA), the formation of which is enhanced by microbial fermentation of fibre, is still controversial. At the present time, our understanding of the effects of SCFA on human metabolism (in gut or systemically) is still limited. The investigators hypothesize that the differential availability of SCFA impacts human metabolism differently. In this placebo controlled, double-blind, randomized crossover pilot study the investigators will validate in overweight/obese healthy male volunteers whether rectal administration of SCFA is a good model for studying the acute metabolic effects of SCFA. For this, it will be investigated if site of administration (in distal or proximal colon) of SCFA differentially affects parameters of substrate and energy metabolism and to test the duration of short-term effects of SCFA administration.