The more I practice medicine, the more I realize that the gut is the most important organ system in the body to create foundational health. In Functional Medicine, we understand that healing the body starts with healing the gut. Just like Hippocrates said, “All disease begins in the gut.” In fact, our gut and the tons of bacteria that reside within it regulate many of our bodily functions, from creating vitamins to controlling our immune system, our brain function, and, of course, our metabolism and weight. The health of the community of microbes living in and on our bodies—100 trillion single-cell organisms, outnumbering human cells 10 to 1—has become a top priority. So the question becomes, how do we fix our guts? My healing took me on a deep dive through all of the ingredients required to make a healthy microbiome and a healthy human. In addition to stress management, gentle movement, targeted therapies, and nourishing foods, I had to provide my microbiome with what it needed to thrive. Once I got rid of the bad stuff, I built up my good bacteria with three specific categories of nutrients: probiotics, prebiotics, and polyphenols.