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Celiac disease is a digestive condition triggered by consumption of the protein gluten, which is found in bread, pasta, cookies, pizza crust and other foods containing wheat, barley or rye. Oats may contain gluten as well. When a person with celiac disease eats foods containing gluten, an immune reaction occurs in the small intestine, resulting in damage to the surface of the small intestine and an inability to absorb certain nutrients from food.

Eventually, decreased absorption of nutrients (malabsorption) can cause vitamin deficiencies that deprive your brain, peripheral nervous system, bones, liver and other organs of vital nourishment, which can lead to other illnesses. This is especially serious in children, who need proper nutrition to develop and grow.

Also known as celiac sprue, nontropical sprue and gluten-sensitive enteropathy, celiac disease occurs in people who have a susceptibility to gluten intolerance. Some speculate that celiac disease has been around since humankind switched from a foraging diet of meat and nuts to a cultivated diet including grains such as wheat. Nonetheless, it has only been in the last 50 years that researchers have gained a better understanding of the condition and how to treat it.

No treatment can cure celiac disease. However, you can effectively manage celiac disease through changing your diet.

There are no typical signs and symptoms of celiac disease. Most people with the disease have general complaints such as intermittent diarrhea, abdominal pain and bloating. Sometimes people with celiac disease may have no gastrointestinal symptoms at all. The symptoms of celiac disease can also mimic those of other conditions, such as irritable bowel syndrome, gastric ulcers, Crohn's disease, parasite infections, anemia, skin disorders or a nervous condition.

Celiac disease may also present itself in less obvious ways, including irritability or depression, stomach upset, joint pain, muscle cramps, skin rash, mouth sores, dental and bone disorders, and tingling in the legs and feet (neuropathy).

Some indications of malabsorption that may result from celiac disease include:

• Weight loss
• Diarrhea
• Abdominal cramps, gas and bloating
• General weakness
• Foul-smelling or grayish stools that may be fatty or oily, including stools that float
• Stunted growth (in children)
• Osteoporosis

Dermatitis herpetiformis is an itchy, blistering skin disease that also stems from gluten intolerance. The rash usually occurs on the elbows, knees and buttocks. Dermatitis herpetiformis can cause significant intestinal damage identical to that of celiac disease. However, it may not produce noticeable digestive symptoms. This disease is treated with a gluten-free diet, in addition to medication to control the rash.

Normally, your small intestine is lined with tiny, hair-like projections called villi. Resembling the deep pile of a plush carpet on a microscopic scale, villi work to absorb vitamins, minerals and other nutrients from the food you eat. Celiac disease results in damage to the villi. Without villi, the inner surface of the small intestine becomes less like a plush carpet and more like a tile floor, and your body is unable to digest and absorb nutrients necessary for health and growth. Instead, nutrients such as fat, protein, vitamins and minerals are eliminated with your stool.

The exact cause of celiac disease is unknown. What is known is that the disease is often inherited. If someone in your immediate family has it, chances are 10 percent to 20 percent that you may have it too. It can occur at any age, although symptoms don't appear until gluten is introduced into the diet.

Many times, for unclear reasons, the disease emerges after some form of trauma: an infection, a physical injury, pregnancy, severe stress or surgery.

Celiac disease may be much more common in the United States than previously believed. One multicenter study of more than 13,000 people, published in February 2003, found that one in 133 study participants had the disease. Among study participants closely related to someone with celiac disease, such as a parent or sibling, the prevalence was even higher: one in 22. Another study, from Olmsted County, Minn., found that the number of new area cases being diagnosed was nine times what it had been 20 years ago.

Part of the reason for the previous underdiagnosis of celiac disease may be because the disorder resembles several other conditions that can cause malabsorption. Another reason may be that if doctors believe a condition to be rare, they may look to more common disorders to explain a person's signs and symptoms. In addition, specific blood tests now allow for diagnosis of people with celiac disease who have very mild signs and symptoms or none at all.

Although celiac disease can affect anyone, it tends to be more common in people of European descent and people with disorders caused by a reaction of the immune system (autoimmune disorders), such as:

• Lupus erythematosus
• Type 1 diabetes
• Rheumatoid arthritis
• Autoimmune thyroid disease

If you notice or experience any of the signs or symptoms common to celiac disease, see your doctor. If someone in your family is known to have celiac disease, you may need to be tested. Starting the process will help you avoid complications associated with not treating the disease, such as osteoporosis, anemia and certain types of cancer.

Seek medical attention for a child who is pale, irritable, fails to grow and who has a potbelly, flat buttocks and malodorous, bulky stools. Many other conditions can cause these same signs and symptoms, so it's important to talk to your doctor before trying a gluten-free diet.

People with celiac disease carry higher than normal levels of certain antibodies (anti-gliadin, anti-endomysium and anti-tissue transglutaminase). Antibodies are specialized proteins that are part of your immune system and work to eliminate foreign substances in your body. In people with celiac disease, their immune systems may be recognizing gluten as a foreign substance and producing elevated levels of antibodies to get rid of it.

A blood test can detect high levels of these antibodies and is used to initially detect those who are most likely to have the disease and who may need further testing. To confirm the diagnosis, your doctor may need to microscopically examine a small portion of intestinal tissue to check for damage to the villi. To do this, your doctor inserts a thin, flexible tube (endoscope) through your mouth, esophagus and stomach into your small intestine and takes a sample of intestinal tissue.

A trial of a gluten-free diet also can confirm a diagnosis, but it's important that you not go on such a diet before seeking a medical evaluation. Doing so may change the results of blood tests and biopsies so that they appear to be normal.

Left untreated, celiac disease can lead to several complications:

• Malnutrition. Untreated celiac disease can lead to malabsorption, which in turn can lead to malnutrition. This occurs in spite of what appears to be an adequate diet. Because vital nutrients are lost in the stool rather than absorbed in the bloodstream, malabsorption can cause a deficiency in vitamins A, B-12, D, E and K, and folate, resulting in anemia and weight loss. Malnutrition can cause stunted growth in children and delay their development.
• Loss of calcium and bone density. With continued loss of fat in the stool, calcium and vitamin D may be lost in excessive amounts. This may result in a bone disorder called osteomalacia, a softening of the bone also known as rickets in children, and loss of bone density (osteoporosis), a condition that leaves your bones fragile and prone to fracture. In addition, lack of calcium absorption can lead to a certain type of kidney stone (calcium oxalate stone).
• Lactose intolerance. Because of damage to your small intestine from gluten, foods that don't contain gluten also may cause abdominal pain and diarrhea. Some people with celiac disease aren't able to tolerate milk sugar (lactose) found in dairy products, a condition called lactose intolerance. If this is the case, you need to limit food and beverages containing lactose as well as those containing gluten. Once your intestine has healed, you may be able to tolerate dairy products again. However, some people may continue to experience lactose intolerance despite successful management of celiac disease. If you're among this group, you'll need to limit products that contain lactose indefinitely.
• Cancer. People with celiac disease who don't maintain a gluten-free diet also have a greater chance of getting one of several forms of cancer, especially intestinal lymphoma and bowel cancer.
• Neurological complications. Celiac disease has also been associated with disorders of the nervous system, including seizures (epilepsy) and nerve damage (peripheral neuropathy).

Celiac disease has no cure, but you can effectively manage the disease through changing your diet. Once gluten is removed from your diet, inflammation in your small intestine will begin to subside, usually within several weeks. If your nutritional deficiencies are severe, you may need to take vitamin and mineral supplements recommended by your doctor or dietitian to help correct these deficiencies. Complete healing and regrowth of the villi may take several months in younger people and as long as two to three years in older people.

Improvements after starting a gluten-free diet may be especially dramatic in children. Not only do their physical symptoms improve, but also their behavior improves. In addition, their growth starts to pick up.

Avoiding gluten is essential
To manage the disease and prevent complications, it's crucial that you avoid all foods that contain gluten. That means all foods or food ingredients made from many grains, including wheat, barley and rye. This includes any type of wheat (including farina, graham flour, semolina and durum), barley, rye, bulgur, Kamut, kasha, matzo meal, spelt and triticale. Amaranth, buckwheat and quinoa are gluten-free as grown, but may be contaminated by other grains during harvesting and processing. Cross-contamination may also occur if gluten-free products are prepared in unwashed bowls previously containing gluten products. Oats may not be harmful for most people with celiac disease, but oat products are frequently contaminated with wheat, so it's best to avoid oats as well.

The question of whether people on a gluten-free diet can eat pure oat products remains a subject of scientific debate. Difficulties in identifying the precise components responsible for the immune response and the chemical differences between wheat and oats have contributed to the controversy.

There are still many basic foods allowed in a gluten-free diet. These include:

• Fresh meats, fish and poultry (not breaded or marinated)
• Most dairy products
• Fruits
• Vegetables
• Rice
• Potatoes
• Gluten-free flours (rice, soy, corn, potato)

Most foods made from grains contain gluten. Avoid these foods unless they're labeled as gluten-free or made with corn, rice, soy or other gluten-free grain:

• Breads
• Cereals
• Crackers
• Pasta
• Cookies
• Cakes and pies
• Gravies
• Sauces

Many other foods have ingredients that contain gluten. Grains containing gluten are often used in food additives such as malt flavoring, modified food starch and others. Other sources of gluten that might come as a surprise include medications and vitamins that use gluten as a binding agent, lipstick, postage stamps and contamination of gluten-free foods with foods containing gluten. Cross-contamination may occur anywhere ingredients come together, such as a cutting board. You may also be exposed to gluten by using the same utensils as others, such as a bread knife, or by sharing the same condiment containers.

Gluten-free products abound
Fortunately for bread and pasta lovers with celiac disease, there are an increasing number of gluten-free products on the market. If you can't find any at your local bakery or grocery store, check with a celiac support group or the Internet for availability. In fact, there are gluten-free substitutes for many gluten-containing foods, from brownies to beer. In many cities there are specialty grocery stores that carry gluten-free foods.

Identifying gluten-free foods can be difficult. Because a gluten-free diet needs to be strictly followed, you may wish to consult a registered dietitian who is experienced in teaching the gluten-free diet. A dietitian can advise you on how to best maintain the nutritional quality of your diet and help you come up with gluten-free alternatives. She or he will also help you identify your need for vitamin, calcium and mineral supplements. Revisiting the dietitian over the years will help keep you up-to-date on newer food products as well as answer your questions.

What if you eat gluten?
If you accidentally eat a product that contains gluten, you may experience abdominal pain and diarrhea. Some people experience no symptoms after eating gluten, but this doesn't mean it's not hurting them. Even trace amounts of gluten in your diet can be damaging, whether or not they cause signs or symptoms. Going on and off a gluten-free diet can lead to serious complications.

Most people with celiac disease who follow a gluten-free diet have a complete recovery. Only a small percentage of people who have severely damaged small intestines don't improve with a gluten-free diet. When diet isn't effective, treatment often includes medications to help control intestinal inflammation and other conditions resulting from malabsorption.

Because celiac disease can lead to many complications, people who don't respond to dietary changes need frequent monitoring by their doctors for other health conditions.

Following a gluten-free diet may leave you angry and frustrated, understandably so. But with time, patience and a little creativity, you'll find there are many foods that you can still eat and enjoy. Following are some tips to help you on your way to a safe and healthy diet.

Read food labels
Food labels are your lifeline to better health. Always read the food label before you purchase any product. Some foods that may appear acceptable, such as rice or corn cereals, may contain gluten. What's more, a manufacturer may change a product's ingredients at any time. A food that was once gluten-free no longer may be. Unless you read the label every time you shop, you won't know this.

In July 2004, the U.S. Congress passed a bill requiring products containing wheat, milk, soy, peanuts, tree nuts, fish, shellfish or eggs to say so in plain English on the product's label. The bill also requires the U.S. Food and Drug Administration to develop a standard definition of "gluten-free" to make it easier for shoppers with celiac disease to identify products.

Call the manufacturer
If you can't tell by the label if a food contains gluten, don't eat it until you check with the product's manufacturer. Some support groups produce a gluten-free shopper's guide that can save you time at the market, although it may not be as current as that obtained from the manufacturer.

Adapt your favorite recipes
If your favorite foods contain gluten, don't fret yet. You may be able to make a few changes in the recipes that will allow you to still enjoy them. Here are some helpful tips for the kitchen.

For 1 tablespoon of wheat flour, substitute one of these:

• 1 1/2 teaspoons cornstarch
• 1 1/2 teaspoons potato starch
• 1 1/2 teaspoons arrowroot starch
• 1 1/2 teaspoons rice flour
• 2 teaspoons quick-cooking tapioca

For 1 cup of wheat flour, substitute one of these:

• 3/4 cup plain cornmeal, coarse
• 1 cup plain cornmeal, fine
• 5/8 cup potato flour
• 3/4 cup rice flour

When using substitute starches and flours, you may find that the recipe turns out best if you bake the food longer and at a lower temperature. For more satisfactory baked products, experiment a bit with baking times, temperature settings and different combinations of substitutes — potato flour and rice flour, for example. In addition, gluten-free cookbooks are available that can give you a good start at recipe adjustments.

Don't be afraid to eat out
Though preparing your own meals is the easiest way to monitor your diet, this doesn't mean you can't eat out. For an enjoyable dining experience, remember the following advice:

• Select places that specialize in the kinds of foods you can eat. You may want to call the restaurant in advance and discuss the menu options and your dietary needs.
• Be a repeat customer. Visit the same restaurants so that you become familiar with their menus and the personnel get to know your needs.
• Seek and share ideas. Ask members of your support group for suggestions on restaurants that serve gluten-free food. If there are enough gluten-sensitive people in your community, it's likely that restaurant owners will try to satisfy your needs. Continue to share with the support group the names of any restaurants that add gluten-free foods to their menus.
• Follow the same practices you do at home. Select simply prepared or fresh foods and avoid all breaded or batter-coated foods, gravies and other foods with obvious or questionable ingredients.

Living with celiac disease isn't always easy. Every day can be a challenge. Over time, however, managing your disease will become second-nature. In the meantime, these suggestions may help you manage more easily:

• Gather information about celiac disease. Talk to your doctor, look for information on the Internet and read books and pamphlets. Find cookbooks directed specifically toward a gluten-free diet. Being informed about your condition can help you take better charge of it.
• Seek out others with celiac disease. Talking to people who know what you're going through can be reassuring. Your doctor may be able to refer you to a celiac disease support group in your community, or you may find one listed on the Internet or in your local paper.
• Don't hesitate to seek guidance. If you're having difficulty coming up with suitable menus, talk to a registered dietitian. A dietitian has extensive knowledge of the nutritional aspects of food and what you can and can't eat. He or she can help you think in more creative ways about your favorite foods.