Celiac disease is an autoimmune disease which is a type of disease that, like multiple sclerosis, rheumatoid arthritis, or lupus is caused by inappropriate activation of the immune system against body tissues. For unknown reasons, when people with celiac disease consume the protein gluten it causes the immune system to react abnormally and attack the lining of the small intestine. This lining is made up of tiny finger-like projections called villi that help increase the area for nutrient absorption. When the immune system attacks this lining, the villi become damaged or destroyed, creating gastrointestinal distress and severely hampering a person’s ability to absorb dietary nutrients.

It is not known why gluten causes the immune system to turn against the cells that line the small intestine, but some indications suggest that the disease is at least partially genetic. If someone from your immediate family has celiac disease, you have between a 5 and 15 percent chance of having it too, a rate that is more than five times higher than in the general population. As with some other autoimmune diseases, celiac disease seems to emerge more commonly after a major life stress or trauma such as pregnancy, major surgery, or severe emotional turmoil.