Symptoms are caused by eating gluten (a mixture of proteins found in wheat and certain other cereals such as barley or rye). (rehydrate.org)
How did gluten, a naturally - occurring protein found in wheat, barley and rye — sources of nutrition for people over thousands of years, become so unhealthy? (ecohealthwellness.com)
Gluten is a group of naturally occurring sticky proteins found in wheat, rye, barley, and triticale (a crossbreed of wheat and rye), and food products containing these grains as ingredients. (gluten.lovetoknow.com)