Celiac disease is an autoimmune disease, which means your body attacks itself.
In Celiac disease, your body makes antibodies to the villi, or small projections in the small intestine. The small intestine is where most of your nutrients are absorbed. When the antibodies attack these villi, the villi become damaged and your intestinal lining becomes like a tile floor instead of a nice fluffy shag carpet. This means that important nutrients are not getting absorbed and you become malnourished and have other health issues such as abdominal bloating, constipation, diarrhea.
About 1 in 133 people have Celiac disease, so it is fairly common. It can be diagnosed by a simple blood test, which tests for the antibodies. You can also have a biopsy done on your small intestine (OUCH).
There are quite a few people who are testing negative for Celiac disease but still have the symptoms of abdominal bloating, constipation and diarrhea. These people should start a gluten free diet. If you get better on a gluten free diet, then you have what we call gluten sensitivity or gluten intolerance. This is very common.
We are also seeing that kids with ADHD, autism, or people with chronic headaches, chronic fatigue, and other conditions cope much better on a gluten free diet.
At the Peace Baker in New Orleans, owner Kelly Baffone makes all of her goodies gluten-free and diary-free. Come visit her bakery to see (and taste!) for yourself: http://www.thepeacebaker.com/