Your gastrointestinal tract – GI or “gut” for short – is a group of organs that start at the mouth and end at the rectum. Its main job is to break down, digest, and absorb food to turn it into the energy and nutrients you need to survive. But the gut is also home to the gut flora or microbiome, a complex world of up to 1,000 bacterial species and other microorganisms that benefit and influence many aspects of human...