Jeroen Raes, researcher on human microbiome, Flanders Institute of Biology explains his discovery in this TED talk, the major breakthrough not just in gastro-intestinal medicine, but in our fundamental knowledge of the human biology. It turns out that there are only three different types of gut bacteria and, just like blood groups, the three types are totally independent of race, sex, age or diet. Such a baffling finding leads to more research of course and Raes is currently testing his idea on a larger group. The implications for Crohn's Disease or obesity could be dramatic.