Watch CBS News Videos Online There’s a disease that American doctors are absolutely terrible at diagnosing. It’s estimated that three million Americans have celiac disease and only a small percentage of them know it. In celiac disease, a component of wheat, rye, and barley called gluten sets off an immune reaction that attacks the intestine and can affect the entire body. Patients are unable to properly absorb essential nutrients because the absorptive fingers (villi) in the small intestin