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.  However, allergic reactions (IgE) to gluten are less common.

Celiac disease is an autoimmune disease, 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 HLA-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.

Almost all people with celiac disease have autoantibodies (IgA anti-tissue transglutamine and IgA anti-endomysium).  Furthermore, patients with Celiac disease are also commonly affected by other kinds of autoimmune diseases such as Type 1 Diabetes or hypothyroidism.95 percent of people with celiac disease have genes of HLA-DQ2 and 5 percent have HLA-DQ8, if you do not have HLA-DQ2 or DQ8, it is very unlikely you will develop Celiac disease.  Though 25-40% of the United States population carries either DQ2 or DQ8, only 2 percent to 3 percent of all people with these genes will ever go on to develop celiac disease. Therefore, the presence of either gene alone is not a guarantee of developing celiac disease.  Genetic testing is useful when there is a discrepancy between blood tests and small intestine biopsy or genetic counselling of family members.

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.

Celiac disease or gluten intolerance is an autoimmune disorder, instead of IgE-mediated food allergy. Therefore, skin testing is not useful.  To make a diagnosis of celiac disease, levels of certain autoantibodies (IgA anti-endomysium and IgA anti-tissue transglutaminase) are measured in the patient’s blood.  If antibody tests and/or symptoms suggest possible celiac disease, a small intestine biopsy to assess mucosal lining damage is indicated to confirm the diagnosis.  Because it takes only several days for the intestinal lining to show improvement, autoantibodies measurement and the results of biopsy are accurate only when the patient is on a gluten-containing diet.  On some occasions, genetic testing which is not affected by a diet, 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 allergy 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.

 

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