The exact cause of gluten intolerance (celiac disease) is unknown. It is an autoimmune disease, meaning the body's immune system is hyperactive and mistakenly attacks its own tissues, in this case the small intestine.

Gluten intolerance is also a genetic disorder, so it runs in families. About 1 in 133 Americans have the condition, but that number may rise to 1 in 22 for those who have an an immediate family member with gluten intolerance, according to the National Institutes of Health (NIH).

For unknown reasons, the disease sometimes emerges after some sort of trauma is experienced, such as an infection, an injury, pregnancy or surgery.

Gluten intolerance will not appear until gluten (a protein found in wheat, barley and rye) is a part of a person's diet. Unfortunately, gluten can be found in a wide variety of foods, including:

• Breads, crackers, cookies, cakes, pie crust and pizza crust
  
  
• Many grains and cereals
  
  
• Pastas such as spaghetti and macaroni
  
  
• Prepared products, such as frozen potatoes or packaged rice mixes
  
  
• Prepared meats containing wheat, rye and barley (e.g., lunch meats, frankfurters, sausages, canned meats, egg substitutes)
  
  
• Canned soups, broths and soup mixes
  
  
• Vegetables in sauce, creamed vegetables, breaded vegetables, some baked beans and some prepared vegetables and salads
  
  
• Beverages such as malted milk, cocoa mixes, some chocolate milk, nondairy creamers, flavored coffee and some herbal tea
  
  
• Alcoholic drinks such as ale, beer, gin and whiskey
  
  
• Flavored yogurts, frozen yogurts and ice creams
  
  
• Processed cheeses such as bleu, stilton, Roquefort and gorgonzola
  
  
• Fats found in some commercial salad dressings, wheat germ oil and many commercial gravies and sauces
  
  
• Candy bars, candies dusted with wheat flour, butterscotch chips, licorice and flavored syrups
  
  
• Dried fruits dusted with wheat flour, some prepared fruits and pie fillings
  
  
• Various flavorings such as curry powder, meat sauces, ketchup, mustard, horseradish, chip dips, most soy sauce, some distilled white vinegar, some cinnamon, some salad dressings, flavoring extracts, seasoning mixes, bouillon and bouillon cubes

It is also important to note than gluten is found in the communion wafers used during certain religious services.

Gluten is not only found in foods. Some medications, vitamins and herbal supplements use gluten as a binding agent. Other sources of gluten include some lipsticks, postage stamps and envelope adhesives.

People with gluten intolerance should always check ingredient labels or inquire with a product’s manufacturer if they are not sure whether gluten is used. Common ingredients that include gluten and should be avoided when they appear on ingredient labels include:

• Bulgur
• Bran
• Brown rice syrup
• Durum
• Farina
• Graham
• Hydrolyzed vegetable protein
• Kaska
• Kamut
• Kasha
• Malt extract or flavorings
• Malt vinegar
• Matzo meal
• Oat gum
• Semolina
• Spelt
• Teff
• Triticale

In addition, some grains are grown as gluten-free but are at high risk of becoming contaminated with other grains during harvesting. These include:

• Amaranth
• Buckwheat
• Quinoa

Some people with gluten intolerance also cannot tolerate oats, but others have no reaction to oats. Research is taking place to determine how oats are likely to affect individuals with gluten intolerance. Until more conclusive information is available, people with gluten intolerance should also avoid eating oats and products made from oats unless their physician has instructed them otherwise, according to the NIH.

Although a gluten-free diet involves elimination of many types of food, there are a number of gluten-free alternatives including gluten-free flours (e.g., corn, potato, soy, rice). These products are available at specialty food stores and some grocery stores.