How Gluten Attacks the Intestine in Celiacs
When someone with celiac disease eats the gluten found in wheat, rye, or barley, everything goes along just fine until the gluten reaches the small intestine.
The first thing that goes wrong is that the grain causes the body — in all humans, not just celiacs — to produce too much of the protein zonulin. This excess causes the junctions between cells in the small intestine to open too much. All sorts of things — like toxins and gluten fragments — can get into the bloodstream, a condition known as leaky gut syndrome.
In people with celiac disease, the body sees gluten fragments as invaders — toxins that shouldn’t be there. So it launches an all-out attack against these invaders, but the body also attacks itself, which is why celiac disease is classified as an autoimmune disease.
Specifically, the body attacks the villi on the lining of the small intestine. As the villi get chopped down — blunted is the technical term — they can no longer be as effective in absorbing nutrients. That’s why you see malabsorption (poor nutrient absorption) and nutritional deficiencies in people with celiac disease who still eat gluten.
Because the food is just passing through without being absorbed the way it’s supposed to be, celiacs sometimes suffer from diarrhea. The small intestine is nearly 22 feet long, and damage from celiac disease starts at the upper part — so there’s lots of small intestine to compensate for the damaged part that’s not able to do its job. That means by the time you develop diarrhea, you’re usually a very sick puppy.