Several blood tests have been developed that can be used to screen people who are at risk for celiac disease. The tests detect the presence of certain antibodies that occur in higher numbers in the blood of people with celiac disease. Antibodies are produced by the body to recognize and fight off antigens or toxins. In people with celiac disease, there are elevated amounts of antigliadin, antiendomysium, and antireticulin antibodies (gliadin, endomysium, and reticulin are the proteins and fibers found in wheat, barley, and rye). A blood test for the antibody to tissue transglutaminase (the specific part of endomysium to which the antibody reacts) was developed that is highly sensitive and accurate about 99% of the time, making it helpful for screening at-risk groups. However, the gold standard for confirming a diagnosis of celiac disease if preliminary blood tests are positive is still an intestinal biopsy, in which a long, thin tube called an endoscope is threaded through the mouth and stomach to the small intestine to take a small tissue sample. If the biopsy reveals villous atrophy, a diagnosis of celiac disease is established. If your doctor suspects celiac disease, you should continue to eat gluten-containing foods until after the biopsy. It is much more difficult to diagnosis celiac disease if gluten has been removed from the diet and healing has already started.
The only treatment for celiac disease is a lifelong, 100% gluten-free diet. Foods that contain gluten are any derivative or variation of wheat, rye, or barley, including bulgur, couscous, triticale, spelt, einkorn, farina, graham flour, semolina, and durum wheat. Until recently, people with celiac disease were told they could not eat oats, but some studies show that oats are not toxic to most people with celiac disease. However, since there is still a debate over this (and there is a strong possibility of gluten from other grains contaminating oats during harvesting, milling, or processing), it is probably best that people with celiac disease not consume oats.
Obvious foods to avoid on a gluten-free diet are most pizzas, breads, bagels, crackers, cookies, cakes, pies, gravies, and flour-based sauces. But there are many less obvious sources of gluten. Communion wafers contain gluten; cooking sprays may contain grain alcohol; malt and malt flavoring, found in cereals, syrups, and beer, are usually made from barley (although some malt products are made from corn). Many licorice candies contain gluten. For this reason, it is very important to read the ingredients list on the label of every food product you purchase and to scrutinize the fine print right down to the food colorings, seasonings, preservatives, and thickeners, many of which contain gluten.
Reading the label may not be enough, however, since some sources of gluten may not be listed on the label. Gum wrappers, for instance, are sometimes dusted with flour to prevent sticking. What’s more, manufacturers sometimes change the way a product is made. Food that was gluten-free last month may have different ingredients this month. The only way to be sure about a product is to call or write the manufacturer. The manufacturer’s name, address, and telephone number appear on the food label. When calling a manufacturer, have the lot number of the food in question available. Many manufacturers also provide lists of their gluten-free foods.
After a while, you will learn to recognize suspect foods and ingredients, but a general rule of thumb is, “If you don’t know what’s in it, don’t eat it.” In the United States, at least, the word “starch” on a food label indicates cornstarch, which is safe to eat. “Modified food starch” or “modified starch,” on the other hand, could be made from corn, arrowroot, tapioca, or wheat. Hydrolyzed vegetable protein, textured vegetable protein, or hydrolyzed plant protein is usually made from wheat or wheat mixed with soy or corn. Vanilla and other flavoring extracts, prebasted turkeys, canned and dried soups, sauces, gravies, luncheon meats, caramel coloring, and soy sauce made from fermented wheat can all contain sources of gluten. Gluten is even used in nonfood items, such as some medicines, toothpastes, mouthwashes, and the glues on mailing labels and envelopes. Ask your pharmacist if any of your medicines contain gluten. Again, calling the manufacturer of a product to ask if it is totally gluten-free is a good habit to get into.