Gut

Our gastrointestinal tract plays a major role in food digestion and nutrient absorption. A variety of digestive enzymes are secreted throughout our digestive system to break down nutrients in order to facilitate their uptake through the small intestine. Most nutrients that reach the colon are subsequently fermented by the gut microbiota. 

Since these fermentation products constitute microbial metabolites and neurotransmitters, the gut is also referred to as endocrine organ (1) – not least, because enteroendocrine cells which line the gastrointestinal tract secrete hormones that can affect a variety of different processes throughout our body (2). However, our gut is also a sensory organ as it is innervated by neurons that belong to the enteric nervous system, with the vagus nerve establishing a link between the gastrointestinal system and the central nervous system (3). The established connection between gut and brain via metabolites and nervous system is described as “gut-brain-axis” and in the literature our gut is often linked to the term “second brain” (4).

Additionally, the gut depicts a natural barrier between the outer and inner world which consists of mainly three different components – the mucosal barrier, the semipermeable intestinal epithelium, and the mucosal immune system – which all taken together protect us from external pathogenic microbes and toxins (5).

At the NGBI we investigate the interplay between nutrition, microbiota composition and gut health in healthy subjects as well as those suffering from an acute or chronic health disorder. An important research area, amongst others, is intestinal permeability since an increase may lead to local and/or systemic inflammation due to translocation of pathogens from the gut lumen into the circulation which has been shown to be associated with a variety of different diseases such as IBD (6).

A frequently applied method to assess intestinal permeability in our in vivo studies is the so-called multi-sugar test (7). This method was for example used in one of our studies assessing sauna dehydration as novel model for intestinal barrier function (8). Furthermore, we are one of the limited number of research centers in the world routinely using Ussing chambers to measure permeability of colonic biopsies (very small tissue specimen obtained during an endoscopic investigation) ex vivo to assess, for instance, the effects of butyrate (9) or dietary fibre (10) on intestinal barrier function.