Right, from what I read, most of us already do have the bacteria in our gut that we need, but yes, we just need to make sure we keep them fed to ensure a healthy population. I don't think most of us actually need to take supplements. We can get both probiotics and prebiotics from food. i.e. yogurt has both prebiotics and probiotics -- i.e. the bacteria is swimming in its own food. If you're a vegan, there are plenty of fermented vegetables and other sources. Thanks for commenting.