Wheat is a grain used to make a wide variety of foods. Wheat allergy is one the most common food allergies in children, but may affect adult as well. People with wheat allergy have IgE (allergic antibody) response to proteins (albumin, globulin, gluten) in wheat. Most allergic reactions involve albumin and globulin. Allergy to gluten are less common.
Celiac disease is an autoimmune disorder, not a food allergy, because it is a result of gluten hypersensitivity. Celiac disease affects about 1 percent of the U.S. population. The name Celiac derives from the Greek word for “hollow”, as in bowels. Gluten is a protein in cereal grains and is comprised of gliadins and glutenins. When people with special genes (HLA DQ2 and/or DQ8) eat wheat, barley, and rye containing gluten, their immune system forms autoantibodies to gluten which, in turn, causes inflammation and attack of the intestinal lining. Absorption of the nutrients in food throughout the intestines is, therefore, affected. Patients with celiac disease are also commonly affected by other kinds of autoimmune diseases.
Typically, celiac disease symptoms manifest themselves at 6 to 24 months of age, following the introduction of cereal into the diet. Symptoms include poor absorption of nutrients by the intestines, impaired growth, abnormal stools, abdominal distension, poor appetite, or irritability. In adults, the symptoms may be quite varied, from severe weight loss and diarrhea to subtle abdominal complaints. To make a diagnosis of celiac disease, physicians measure levels of certain autoantibodies (IgA anti-endomysium and IgA anti-tissue transglutaminase) in the patient’s blood. If antibody tests and/or symptoms suggest possible celiac disease, a small intestine biopsy is indicated to confirm the diagnosis. On some occasions, genetic testing is very helpful to rule out celiac disease.
Those with wheat allergy usually outgrow it, but those with celiac disease do not lose their sensitivity to gluten. Therefore, they require a life-long restriction from wheat and other grains containing gluten, such as rye, oats, and barley. A food labeled “wheat-free” that still contains gluten ingredients would be safe for someone with a wheat allergy to consume, but not for someone with celiac disease. Corn and rice contain some gluten, but in these forms, it does not appear to affect people with celiac disease. Although oatmeal doesn’t naturally contain gluten, oats may be contaminated with it during growing and processing. The U.S. Food and Drug Administration does not require manufacturers to disclose gluten on food labels (only wheat), so determining if any given product contains gluten takes some detective work, unless that product is specifically labeled “gluten free”.
Wheat allergies and celiac disease are two separate conditions requiring unique treatment options and presenting different outcomes. The importance of obtaining an accurate diagnosis cannot be overemphasized.