You don’t need a PhD in physiology to know that stress can be hard on the stomach. We’ve all done our own experiments on the subject, intentionally or not. Remember how you felt the last time you spoke in public? Those butterflies weren’t in your head. The impact of stress on the stomach goes far beyond indigestion, however. In recent years, doctors have uncovered a remarkably complex connection between the brain and the digestive system. The entire system is extremely sensitive to our moods. In fact, experts now see stress as a major player in a wide range of digestive problems, including irritable bowel syndrome, indigestion, and heartburn. People with digestive problems often scoff at the idea that stress could be at the root of their problems. To them, it sounds like “blaming the victim.” Robert Sapolsky, a Stanford University stress expert and author of the best-selling book Why Zebras …