CELIAC DISEASE OVERVIEW
Celiac disease is a condition in which the immune system responds abnormally to a protein called gluten, which then leads to damage to the lining of the small intestine. Gluten is found in wheat, rye, barley, and a multitude of prepared foods. Celiac disease is also known as gluten-sensitive enteropathy and celiac sprue. The small intestine is responsible for absorbing food and nutrients. Thus, damage to the lining of the small intestines can lead to difficulty absorbing important nutrients; this problem is referred to as malabsorption. Although celiac disease cannot be cured, avoiding gluten usually stops the damage to the intestinal lining and the malabsorption that results. Celiac disease can occur in people of any age and it affects both genders.
CELIAC DISEASE SYMPTOMS
The symptoms of celiac disease vary from one person to another. In its mildest form, there may be no symptoms whatsoever. However, even if you have no symptoms, you may not be absorbing nutrients adequately, which can be detected with blood tests. As an example, you can develop a low blood count as a result of decreased iron absorption.
Some people have bothersome symptoms of celiac disease, including diarrhea, weight loss, abdominal discomfort, excessive gas, and other signs and symptoms caused by vitamin and nutrient deficiencies.
Some conditions are more common in people with celiac disease, including:
- Osteopenia or osteoporosis (weakening of the bones)
- Iron deficiency anemia (low blood count due to lack of iron)
- Diabetes mellitus (type I or so-called juvenile onset diabetes mellitus)
- Thyroid problems (usually hypothyroidism, an underactive thyroid)
- A skin disease called dermatitis herpetiformis
- Nervous system disorders
- Liver disease
CELIAC DISEASE CAUSES
It is not clear what causes celiac disease. A combination of environmental and genetic factors is important. Celiac disease occurs widely in Europe, North and South Americas, Australia, North Africa, the Middle East, and in South Asia.
Celiac disease occurs rarely in people from other parts of Asia or sub-Saharan Africa.
CELIAC DISEASE DIAGNOSIS
Celiac disease can be difficult to diagnose because the signs and symptoms are similar to other conditions. Fortunately, testing is available that can easily distinguish untreated celiac disease from other disorders.
Blood tests - A blood test can determine the blood level of antibodies (proteins) that become elevated in people with celiac disease. Over 95 percent of people with untreated celiac disease have elevated antibody levels (called IgA tissue transglutaminase, or IgA tTG), while these levels are rarely elevated in those without celiac disease. Levels of other antibodies (called IgA or IgG deamidated gliadin peptide) are also usually abnormally high in untreated celiac disease. Before having these tests, it is important to continue eating a normal diet, including foods that contain gluten. Avoiding or eliminating gluten could cause the antibody levels to fall to normal, delaying the diagnosis.
Small intestine biopsy - If your blood test is positive, the diagnosis must be confirmed by examining a small sample of the intestinal lining with a microscope. The sample (called a biopsy) is usually collected during an upper endoscopy, a test that involves swallowing a small flexible instrument with a camera. The camera allows a physician to examine the upper part of the gastrointestinal system and remove a small piece (biopsy) of the small intestine. The biopsy is not painful. In people with celiac disease, the lining of the small intestine has a characteristic appearance when viewed with a microscope. Normally, the lining has distinct finger-like structures, which are called villi. Villi allow the small intestine to absorb nutrients. The villi become flattened in people with celiac disease. Once you stop eating gluten, the villi can resume a normal growth pattern. More than 70 percent of people begin to feel better within two weeks
after stopping gluten.
One way to determine if the gluten-free diet is working is to monitor the levels of antibodies in your blood. If your levels decline on a gluten-free diet, this usually indicates that the diet has been effective.
"Potential" celiac disease - People with a positive IgA endomysial antibody test and/or a positive IgA-tTG test and a normal small bowel biopsy are considered to have potential celiac disease. People with potential celiac disease are not usually advised to eat a gluten-free diet. However, ongoing monitoring (with a blood test) is recommended and a repeat biopsy may be needed if you develop symptoms. Biopsies should be taken from several areas in the bowel since the abnormality can be patchy.
"Silent" celiac disease - If you have a positive blood test for celiac disease and an abnormal small bowel biopsy, but you have no other symptoms of celiac disease, you are said to have "silent" celiac disease. It is not clear if people with silent celiac disease should eat a gluten-free diet. Blood tests for malabsorption are recommended, and a gluten-free diet may be needed if you have evidence of malabsorption.
Testing for malabsorption - You should be tested for nutritional deficiencies if your blood test or bowel biopsy indicates celiac disease. Common tests include measurement of iron, folic acid, or vitamin B12, and vitamin D. You may have other tests if you have signs of mineral or fat deficiency, such as changes in taste or smell, poor appetite, changes in your nails, hair, or skin, or diarrhea.
Other tests - Other standard tests include a CBC (complete blood count), lipid levels (total cholesterol, HDL, LDL, and triglycerides), and thyroid levels. Once your celiac antibody levels return to normal, you should have a repeat test once
Many clinicians recommend a test for bone loss 12 months after beginning a gluten-free diet. One method involves using a bone density (DEXA) scan to measures your bone density. The test is not painful and is similar to having an x-ray. If you have significant bone loss, you may need calcium and vitamin D supplements, an exercise program, and possibly a medicine to stop bone loss and encourage new bone growth.
CELIAC DISEASE COMPLICATIONS
Nonresponsive celiac disease - Approximately 10 percent of people with celiac disease experience ongoing symptoms despite adhering to a gluten-free diet. There are many causes, including other food intolerances such as fructose (or other fermentable carbohydrate) malabsorption, food allergies, bacterial overgrowth in the small intestine or conditions such as microscopic colitis, irritable bowel syndrome, pancreatic exocrine insufficiency, or refractory celiac disease. However, the most common cause is ongoing, often inadvertent, gluten ingestion. Thus, an essential first step in evaluating nonresponsive celiac disease is consultation with an experienced celiac dietitian.
Refractory celiac disease - A small percentage of people develop intestinal symptoms that do not improve despite use of a strict gluten-free diet. In other cases, intestinal symptoms initially improve with dietary changes but then return.
People who have these problems may have refractory celiac disease. The cause of this problem is not known. Treatment involves medications that suppress the immune system's abnormal response (eg, steroids). Treatment is important
because people with untreated celiac disease can develop anemia, bone loss, and other consequences of malabsorption.
Ulcerative jejunitis - People with refractory celiac disease who do not improve with steroids (glucocorticoids) may have a condition known as ulcerative jejunitis. This condition causes the small intestine to develop multiple ulcers that do not
heal; other symptoms may include a lack of appetite, weight loss, abdominal pain, diarrhea, and fever. This condition can be difficult to treat. Treatment may require surgery to remove the ulcerated area.
Lymphoma - Cancer of the intestinal lymph system (lymphoma) is an uncommon complication of celiac disease. Avoiding gluten can usually prevent this complication.
Skin conditions - Celiac disease is associated with a number of skin disorders, of which dermatitis herpetiformis is the most common. Dermatitis herpetiformis is characterized by intensely itchy, raised, fluid-filled areas on the skin, usually located on the elbows, knees, buttocks, lower back, face, neck, trunk, and occasionally within the mouth.
The most bothersome symptoms are itching and burning. This feeling is quickly relieved when the blister ruptures. Scratching causes the area to rupture, dry up, and leave an area of darkened skin and scarring. The condition will improve after eliminating gluten from the diet, although it may take several weeks to see significant improvement. In the meantime, an oral medication called dapsone may be recommended. Dapsone relieves the itching but does not heal the lining of the small intestine; thus, the gluten-free diet is the most effective therapy for those with dermatitis herpetiformis.
CELIAC DISEASE TREATMENT
Gluten-free diet - The cornerstone of treatment for celiac disease is complete elimination of gluten from the diet for life. Gluten is the group of proteins found in wheat, rye, and barley that are toxic to those with celiac disease. Gluten is not only contained in these most commonly consumed grains in the Western world, but is also hidden as an ingredient in a large number of prepared foods as well as medications and supplements. Maintaining a gluten-free diet can be a challenging task that may require major lifestyle adjustments. Strict gluten avoidance is recommended since even small amounts can aggravate the disease. It is important to avoid both eating gluten and being exposed to flour particles in the air.
Get help from a dietitian - An experienced celiac dietitian can help you to learn how to eat a gluten-free diet, what foods to avoid, and what foods to add for a nutritionally balanced diet. Your dietitian can also recommend gluten-free vitamin/mineral and other supplements, as needed. Your celiac dietitian can also educate you on shopping, food preparation, and lifestyle resources. Excellent resources are also available from celiac medical centers, organizations, and support groups. Fortunately, life on a gluten-free diet becomes increasingly easier each year due to the rising popularity of gluten-free foods among those with celiac disease, nonceliac gluten sensitivity, and wheat allergies. Excellent gluten-free substitute foods are now widely available in supermarkets, health food stores, and online.
Avoid foods containing wheat, rye, barley, malt, brewer's yeast, oats (unless pure, uncontaminated, labeled gluten-free oats), and yeast extract and autolyzed yeast extract (unless the source is identified as gluten-free). "Malt" means "barley malt" unless another grain source is named, such as "corn malt." The US Food and Drug Administration (FDA) and the United States Department of Agriculture have different regulations around gluten-free food labeling. According to the FDA regulations issued in August 2013, foods with "gluten-free" labeling must contain less than 20 parts per million (ppm) of gluten. The following table has a list of prepared foods that contain or may contain gluten. Naturally gluten-free foods include rice, wild rice, corn, potato, and other foods listed in the table. These foods may be contaminated with wheat, barley, or rye. Choose labeled gluten-free versions of these products. Exceptions are fresh corn, fresh potatoes, nuts and seeds in their shells, dried lentils (legumes), and dried beans. These foods may not be labeled gluten-free but are still considered safe to eat. Pick through and rinse dried legumes and dried beans.
If a food is regulated by the FDA and is not labeled gluten-free (such as prepared foods and condiments), read the ingredients list and "contains" statement carefully. The word "wheat" will be included if the product is FDA regulated and contains wheat protein. If you do not see any of the following words on the label of an FDA-regulated food (wheat, rye, barley, malt, brewer's yeast, oats, yeast extract, and autolyzed yeast extract) then the product is unlikely to include any gluten-containing ingredients. However, the Food Allergen Consumer Protection Act pertains to ingredients only. It does not cover wheat protein that may be in a product unintentionally due to cross-contact. Distilled alcoholic beverages and vinegars, as well as wine, are gluten-free unless gluten-containing flavorings are added after production. However, malt beverages, including beer, are not considered gluten-free. There are specially produced beers that do not use malted barley that are labeled gluten-free and can be consumed on a gluten-free diet. Please note that malt vinegar is not gluten-free.
You may not tolerate dairy products initially while your intestines are healing. If you tolerated lactose before your diagnosis, you may be able to tolerate it again after the intestine heals. In the meantime, choose lactose-reduced or lactose-free products if your symptoms are worsened by dairy products. Choose labeled gluten-free, dairy-free alternatives, such as rice, soy, or nut (almond, hazelnut) beverages that are enriched with calcium and vitamin D. Keep in mind that gluten-free rice and nut milks have minimal protein per serving compared with cow's or soy milk. Gluten-free lactase enzyme supplements are also available, which may help you to tolerate foods that contain lactose.
Discuss your need for calcium and vitamin D supplements with your healthcare provider or dietitian. A small percentage of people with celiac disease cannot tolerate gluten-free oats for several reasons. If you choose to eat gluten-free oats, first talk to your doctor who can check your IgA-tTG level and monitor any symptoms. In addition, choose only specially produced gluten-free oats. Limit your intake of gluten-free oats to no more than 50 grams (approximately 1/2 cup dry rolled oats or 1/4 cup dry steel-cut oats) per day. If tolerated, you may be able to discuss eating more than 1/2 cup per day under the supervision of your doctor.
Is gluten avoidance really necessary? - People who have no symptoms of celiac disease often find it difficult to follow a strict gluten-free diet. Indeed, some healthcare providers have questioned the need for a gluten-free diet in this group. However, certain factors support a gluten-free diet, even in those without symptoms: Strictly following a gluten-free diet sometimes helps you to feel more energetic and have an improved sense of health and wellbeing. Some people with celiac disease have vitamin or nutrient deficiencies that do not cause them to feel ill, such as anemia due to iron deficiency or bone loss due to vitamin D deficiency. However, these deficiencies can cause problems over the long term.
Untreated celiac disease can increase the risk of developing certain types of gastrointestinal cancer. This risk can be reduced by eating a gluten-free diet.
IMPLICATIONS FOR THE FAMILY
Eliminating gluten requires a major lifestyle change for you as well as your family. However, with time and practice, it will be easier to know which foods, medications, supplements, and oral care products contain gluten and what alternatives are available. Although eating out can be challenging initially, restaurants have become increasingly interested in serving people with celiac disease by offering a gluten-free menu or ingredient substitutions. Families also need to be aware of their increased risk of celiac disease. Thus, your first-degree relatives (parents, brothers, sisters, children) should consider being tested, especially if anyone has signs or symptoms of the condition. Testing is typically done with a blood antibody test, as described above.
CELIAC DISEASE OVERVIEW