Book excerpt: From Dr. Peter H. R. Green, internationally renowned expert on celiac disease and director of the Celiac Disease Center at Columbia University, and medical author Rory Jones, an updated fourth edition of the definitive book on celiac disease, one of the most underdiagnosed autoimmune diseases in the U.S. Celiac Disease: A Hidden Epidemic is an indispensable guidebook for anyone with celiac disease as well as for those with gluten intolerance or food sensitivities on a gluten-free diet. Since the last edition in 2016, scientific advances have changed what we know about the disease, how it is diagnosed and treated, and the long-term effect of a gluten-free diet on the brain and body. Celiac disease is a hereditary autoimmune condition that damages the lining of the small intestine so that it cannot properly absorb food. Without essential nutrients, the entire body begins to suffer. The disease is triggered by gluten, a protein found in wheat, rye, and barley. The only “cure” for the disease is a life-long gluten-free diet. The disease affects nearly 1 in every 100 people in the United States—50 percent of whom remain undiagnosed and untreated. Although the primary target of injury is the small intestine, CD can and often does affect the entire body. Complications from the disease can include infertility, liver disease, osteoporosis, anemia, and other autoimmune diseases (such as Type 1 diabetes and Thyroid disease), neurological conditions, and even cancer. This updated fourth edition includes the latest information on CD, gluten intolerance, and gluten sensitivity. The important updates cover everything from new testing devices to advances in therapies that may help prevent gluten from entering and/or harming the intestines, to new research on the long-term effect of the gluten-free diet on our minds and bodies. And more!