Celiac disease, also known as gluten intolerance, is a genetic disorder that affects 1 in 133 Americans. Symptoms of celiac disease can range from the classic features, such as diarrhea, weight loss, and malnutrition, to latent symptoms such as isolated nutrient deficiencies but no gastrointestinal symptoms. The disease mostly affects people of European (especially Northern European) descent, but recent studies show that it also affects Hispanic, Black and Asian populations as well.
Those affected suffer damage to the villi (shortening and villous flattening) in the lamina propria and crypt regions of their intestines when they eat specific food-grain antigens (toxic amino acid sequences) that are found in wheat, rye, and barley.
A gluten-free diet is essential for people who have celiac disease or dermatitis herpetiformis (a gluten induced skin sensitivity). Some people may choose to follow a gluten-free diet for other reasons, although these two diseases are the only ones where a gluten-free diet is considered medically imperative.
Gluten is a mixture of proteins found in some cereals, particularly wheat. It is the gliadin component of gluten which is responsible for celiac disease. A gluten-free diet is not the same as a wheat-free diet, and some gluten-free foods are not wheat free. Despite a good deal of research, it is unknown how or exactly why gluten harms the gut. It is now considered likely that celiac disease involves an abnormal immunologic response, rather than an enzyme deficiency as was suggested in the past.
A gluten-free diet involves the complete avoidance of all foods made from or containing wheat, rye, barley and usually, oats. Some doctors say oats may be permitted, although The Celiac Society advises against the inclusion of oats in a gluten-free diet.