Influence of polysaccharide based dietary fibre on gut microflora and human health-INFIGUT

This project aims at generating new knowledge about the influence of dietary fibres on the gut microflora and to document effects on the human health. The knowledge can be utilized as basis for dietary recommendations and form a basis for development of n ew, health promoting foods. The intestinal microflora has a significant impact on human health and well being. Plant fibres are believed to have a positive impact on the gut flora by stimulation of favourable bacteria. Carbohydrate fermentation generate s health promoting fermentation products, and the fibre itself may stimulate the unspecific immune system. Only limited information is available about the abundance and properties of gut bacteria with abilities to hydrolyze dietary fibres. We want to study if, and how, a range of polysaccharide fibres with different monomers and structures affect the natural gut flora isolated from healthy infants, children and adults, and to characterize the bacteria that are able to use these fibres as growth substr ates. We will concentrate on the hydrolytic species. In vitro fermentations will be applied for evaluation of substrates and characterization of the bacteria. Fibres to be included in the work will be beta-glucans from different sources, arabinoxylans, re sistant starch and alginate. Others will be considered based on the initial results. Interactions of fibres and their degradation and fermentation products with epithelial cells and immunological responses of the fibres will be determined. A mouse model w ill be used to study the influence of fibre on intestinal tumourigenesis. The collection of gut bacteria will be available for future research projects, for studies of other properties of the gut flora, and the model system established through the study may be used for other dietary components or for pharmaceuticals.