The newly established Gut Ecology research area investigates the influence of food compounds on the composition of the gut microbiota, as well as the metabolism of specific nutrients. The latter aspect is investigated in cooperation with the Metabolism research group. Special emphasis is on the interaction of the gut microbiota with secondary plant compounds, especially polyphenols. The biotransformation of such compounds is investigated using either feces cultures or pure gut bacteria cultures, and the metabolites formed are identified and quantified. The influence of nutrients on specific populations of the gut microbiota is determined using quantitative PCR and DGGE, as well as metagenomic analyses.