In this study, we intend to test the ecological and therapeutic functionality of a synbiotic combination of a Bifidobacterium adolescentis strain and the prebiotic galactooligosaccharide (GOS) in a human clinical trial. The synbiotic combination was selected based on a novel in vivo selection; specifically, the strain (BD1) is an human autochthonous gut organism that was enriched in an individual by GOS. Our experiments will test the efficacy of this synbiotic compared to a conventional synbiotic. We hypothesize this rationally selected synbiotic will improve intestinal barrier function in obese adult subjects, thereby preventing endotoxemia and metabolic inflammation, physiologically relevant functions that are increased in obese individuals. Our objectives are to: (1) compare the ability of the test and control synbiotic preparations to alter the gut microbiota in obese individuals; (2) test if GOS supports colonization and metabolic activity of test and control strains in the human gut; (3) compare the ability of the two synbiotic preparations to improve intestinal permeability and endotoxemia in obese subjects; and (4) assess associations between the gut microbiota and the test strain with biomarkers for translocation and endotoxemia.
