We are making ourselves sick. The science of epigenetics is showing us beyond the shadow of a doubt what we’ve always intuitively known—the air we breathe, the foods we eat, the water we drink (or don’t drink), how much we sleep, how we handle stress, whether we exercise, and the other lifestyle choices we make—all dictate whether we are healthy or develop serious diseases like cancer. According to the National Cancer Institute, only 5 to 10 percent of all cancers are caused by genetic mutations, yet they receive a lot of attention. As soon as people get the dreaded diagnosis, they start examining the health histories of their relatives to find the genetic connection and explain why they are sick. And while we see cancers that run in families and assume they are genetic, the truth is, we’ve either shared the same toxic environment or inherited our parents’ bad habits. Do …