Gluten Intolerance – Causes, Signs and symptoms

Gluten Intolerance

Also called: Gluten Sensitive Enteropathy, Nontropical Sprue, Celiac Disease, Celiac Sprue


Gluten intolerance, also called celiac disease, is an extreme sensitivity to the protein gluten, which is found in wheat, barley and rye.

Though the symptoms may appear similar, gluten intolerance is not a food allergy but rather an inherited autoimmune disease. The body’s immune system mistakenly identifies gluten as harmful. This leads to inflammation and damage in the small intestine. A food allergy to wheat results instead in an allergic response, with symptoms such as itchiness and rash.

Damage to the small intestine can occur when a person with gluten intolerance consumes even a small amount of gluten. Symptoms can include abdominal pain and diarrhea.

The intestinal damage weakens the body’s ability to absorb nutrients from food. This can lead to malnutrition and related conditions, such as weight loss, osteoporosis and infertility. Patients may also face increased risk of conditions including diabetes, thyroid disease, lupus, rheumatoid arthritis and some cancers.

It is important to note that although some people with gluten intolerance suffer severe symptoms, others have no symptoms. People who do not experience symptoms, however, may still suffer damage to the small intestine.

Diagnosis of gluten intolerance usually involves blood tests and may include a biopsy of the small intestine.

Gluten intolerance can be successfully treated by removing all gluten from the diet. This includes avoiding breads, cereals, cookies and all other types of foods or other products with wheat, barley or rye as an ingredient, including some beers, lipsticks, postage stamps, medications and vitamins. Some patients cannot tolerate oats either.

People who suspect they may have gluten intolerance should immediately consult a physician. Symptoms may present themselves late in life and are known to sometimes appear after a traumatic event such as an injury, pregnancy or severe stress.

About gluten intolerance (celiac disease)

People with gluten intolerance (celiac disease) are extremely sensitive to the protein gluten, which is found in wheat, barley, rye and possibly oats. The condition involves an inappropriate immune system reaction to gluten that causes inflammation in the small intestine.

This inflammation damages the interior wall of the small intestine, specifically harming tiny protrusions called villi. These villi are responsible for absorbing nutrients into the bloodstream. The loss of the villi often leads to malnutrition and related complications such as bone disease.

Although patients with other food intolerances may tolerate “small amounts” of the problem food without triggering a reaction, people with gluten intolerance cannot safely consume any amount of gluten. Though some people may believe they can tolerate a small amount of gluten because symptoms do not occur, ingestion can still result in damage to the small intestine.

Though symptoms may appear similar, gluten intolerance is not a food allergy because the immune response to gluten is different than an allergic reaction. The immune system turns upon itself with both conditions, but gluten intolerance results in specific damage to the small intestine. A food allergy, though, often results in a more generalized reaction that occurs as histamines travel throughout the bloodstream. Although it is possible to have a food allergy to wheat and wheat protein, this condition is not related to gluten intolerance.

About 2 million Americans suffer from celiac disease, according to the National Institutes of Health. It is not known what causes gluten intolerance, though genetics has a role. A person is more likely to have gluten intolerance if an immediate family member also has the condition. For some reason, also unknown, the condition is sometimes triggered by a trauma such as injury, pregnancy or severe stress.

Gluten intolerance can lead to a variety of complications if not treated by a physician. The most frequent complications involve malabsorption (the inability of food to properly digest and move through the wall of the intestines into the bloodstream) and malnutrition (a lack of sufficient vitamins or minerals that results from the poor absorption). This lack of proper nutrition leads to many of the symptoms and complications associated with gluten intolerance. Because levels of malabsorption vary in each case, symptoms also vary in type and intensity. Some people with gluten intolerance suffer severe symptoms, but others suffer from none at all.

In addition to the dangers of malnutrition and malabsorption, gluten intolerance can increase a person’s risk of developing a number of serious conditions. These include type 1 diabetes, lupus, rheumatoid arthritis, other autoimmune diseases and certain forms of cancer.

Conditions related to gluten intolerance

Because of the damage that gluten intolerance (celiac disease) causes to the small intestine and the resulting problems with malabsorption, an individual with this condition is at risk for several types of health problems, including:

  • Malnutrition. A lack of sufficient vitamins or minerals that results from the poor absorption of nutrients from food (malabsorption). People with gluten intolerance can become deficient in vitamins A, B12, D, E and K and folate. This may result in weight loss, anemia and other problems.

  • Cancer. Lymphoma (a form of cancer that appears in the lymph nodes) and adenocarcinoma (a form of cancer that originates in the cells lining certain internal organs) can possibly develop in the intestine. Physicians will often test patients for these cancers if symptoms of gluten intolerance persist even after maintaining a gluten-free diet. Other solid tumors of the small intestine and perhaps the esophagus are also seen more often in patients with celiac disease.

  • Osteoporosis. Poor absorption of calcium and vitamin D can lead to this brittle-bone condition. Also, osteomalacia or disordered mineralization is commonly seen in children. Calcium and vitamin D may be lost through high-fat stools. This may cause thinning or softening of the bones, which can lead to fractures. Supplementing a gluten-free diet with other sources of vitamins and minerals can substantially lower the risk of developing osteoporosis and osteomalacia.

  • Kidney stones. This condition may result from low absorption of calcium, due to the fat lost in stools.

  • Miscarriage or congenital malformation. If gluten intolerance goes untreated in women, certain neural tube defects can result, complicating a pregnancy or resulting in birth defects.

  • Preterm delivery. There is some evidence that undetected gluten intolerance raises the risk of preterm delivery in pregnant women. Diagnosing and treating the condition before the pregnancy can greatly lower these risks. Women with a gluten intolerance who plan to become pregnant should discuss their condition with a physician first.

  • Short stature. If a child fails to receive the proper nutrients, growth can be inhibited.

  • Seizures. The inadequate absorption of folic acid can lead to calcium deposits forming in the brain, causing seizures and nerve damage.

  • Lactose intolerance. Damage to the small intestine may prevent milk sugar (lactose) from properly digesting. Abdominal pain and diarrhea can result.

  • Infections. Patients may be at increased risk for serious infections such as tuberculosis, possibly because of poor absorption of vitamin D, researchers have found.

There are several other types of autoimmune diseases linked to gluten intolerance. Though the relationship between these conditions is not completely clear, the link may be genetic. These conditions include:

  • Dermatitis herpetiformis (DH). An autoimmune disease of the skin caused by gluten intolerance. It is characterized by the appearance of severe itchy, blistering skin usually on the elbows, knees and buttocks. Individuals with DH often do not have the digestive symptoms normally associated with gluten intolerance, though the intestinal damage is often present.

  • Thyroid disease. Any condition that disrupts the thyroid gland’s natural ability to control the key functions of the body. Thyroid hormones are important to metabolism (the conversion of food to energy). Disruption of thyroid function can result in too many (hyperthyroidism) or too few (hypothyroidism) thyroid hormones circulating in the blood.

  • Type 1 diabetes. Condition where the pancreas cannot produce enough insulin, preventing the body from using blood glucose as energy. Insulin levels must be controlled with daily injections.

  • Liver disease. Disease which prevents the liver from carrying out its normal functions as a metabolism aid.

  • Sjogren’s syndrome. Condition in which immune cells attack and destroy the glands that produce tears and saliva.

  • Autoimmune polyglandular syndrome. Uncommon group of disorders that may include type 1 diabetes, Addison’s disease (adrenal insufficiency), yeast infections, vitiligo (a skin disease), alopecia (hair loss), pernicious anemia or other conditions.

  • Collagen vascular diseases. A group of immune disorders that affects collagen (a strong, glue-like protein that shapes the structure of bones, tendons and connective tissues). This includes:

    • Rheumatoid arthritis. Inflammatory disease that mainly affects the joints and the surrounding tissues.

    • Lupus (systemic lupus erythematosus, SLE). A chronic inflammatory disorder that can involve the joints, skin, kidneys, blood vessels and other parts of the body.

    • Polyarteritis nodosa. A blood vessel disease that results in the swelling and damage of small and medium-sized arteries.

    • Scleroderma. A connective tissue disease that involves the skin, joints, blood vessels and internal organs. It causes the skin to thicken and/or swell.

    • Dermatomyositis. A disease in which the blood vessels of the skin and muscles become inflamed, creating patchy rashes that are blue or purple in color and muscle weakness.

Another condition related to gluten intolerance is ulcerative jejunoileitis. Patients with this serious condition usually experience ulcerations (breaks on the surface of an organ) and strictures (abnormal narrowing) of the small intestine. This can result in intestinal bleeding, weight loss, abdominal pain and intestinal obstruction. People with ulcerative jejunoileitis are also at a higher risk of developing intestinal lymphomas (a type of cancer). Though this serious complication of gluten intolerance is often fatal, it is rare. Most forms of gluten intolerance can be successfully treated through dietary changes.

Certain conditions can prevent a person with gluten intolerance from responding to a gluten-free diet. Failure to respond to a gluten-free diet usually has a simple solution, such as unknowingly ingesting gluten. However, patients who fail to respond to a gluten-free diet may be screened for advanced forms of gluten intolerance (e.g., refractory celiac disease) or other conditions. These may include:

  • Irritable bowel syndrome. A disorder in which the large intestine (colon) does not function normally, leading to cramping, abdominal pain, bloating, constipation and/or diarrhea.

  • Bacterial overgrowth of the small bowel. A disorder in which higher-than-normal levels of bacteria occur in the small intestine. It can create symptoms such as indigestion, bloating, gas and diarrhea.

  • Microscopic colitis. A condition in which the colon becomes inflamed, leading to diarrhea and abdominal pain.

  • Pancreatic insufficiency. A condition in which the pancreas does not secrete enough enzymes and other chemicals for normal digestion to take place. This can lead to malnutrition.

Types and differences of gluten intolerance

There are several forms of gluten intolerance (celiac disease) that vary in symptoms and severity:

  • Latent celiac disease. Gluten intolerance that does not produce external symptoms such as abdominal pain and diarrhea. However, it does cause intestinal damage. Though difficult to diagnose without external symptoms, it is important to detect this type of intolerance as early as possible to limit long-term damage or complications. Antibody tests and biopsies should be able to detect this type of intolerance.

  • Silent celiac disease. Gluten intolerance that does not produce external symptoms such as abdominal pain and diarrhea. However, it does cause intestinal damage. While difficult to diagnose without external symptoms, it is important to detect this type of intolerance as early as possible to limit long-term damage or complications. Both antibody tests and biopsies should be able to detect this type of intolerance.

  • Refractory celiac disease. A rare form of gluten intolerance in which the condition does not improve even after months of eliminating gluten from the diet. Some physicians consider this disease to actually be a type of cancer. Before diagnosing this condition a physician will be sure to rule out other conditions that display the same symptoms. Corticosteroids are often used to successfully treat refractory celiac disease, though in some cases the intravenous delivery of nutrition is necessary.

  • Collagenous celiac disease. A rare condition in which gluten intolerance results in a large amount of scar tissue accumulating under the intestinal lining. There is no treatment for this usually fatal condition.

Risk factors and potential causes of gluten intolerance

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.

Signs and symptoms of gluten intolerance

The main signs and symptoms associated with gluten intolerance (celiac disease) are due to the inadequate absorption of nutrients from food. This condition results in:

  • Abdominal bloating and pain
  • Diarrhea
  • Constipation
  • Foul-smelling gas and stool
  • Steatorrhea (an increased amount of fat in the stool)

Some of the signs and symptoms associated with gluten intolerance occur as a result of the malnutrition and vitamin deficiencies often caused by the condition. These may include:

  • Anemia (low number of red blood cells) and fatigue. Due to a lack of absorption of vitamin B12 and iron.

  • Weight loss. Due to poor absorption of carbohydrates, proteins and fats.

  • Bone pain, bone weakness and osteoporosis. Due to a lack of absorption of vitamin D.

  • Swelling (often around the ankles and feet). Due to fluid retention.

  • Tingling and numbness from nerve damage. Due to deficiencies of B12 and thiamine.

Other indicators may include behavioral changes, muscle cramps, joint pain, mouth sores, tooth discoloration, itchy rash, weight gain, seizures, missed menstrual periods, infertility or miscarriages.

The signs and symptoms displayed by gluten intolerant individuals vary in type and severity depending on the person. Age is usually a significant factor in how the disease presents itself.

InfantsDiarrhea (common)
Steatorrhea (common)
Abdominal cramps
Muscle wasting
Poor growth
Older childrenDiarrhea (common)
Steatorrhea (common)
Weight loss
Behavioral problems
Short stature
Accelerated osteoporosis

Symptoms may begin in childhood or adulthood. As a child reaches adolescence, the symptoms of gluten intolerance may be reduced or disappear, though they often return during adulthood.

It is also important to note that although some people with gluten tolerance suffer severe symptoms, some suffer none at all.

Diagnosis methods for gluten intolerance

Several diagnostic methods are available when gluten intolerance (celiac disease) is suspected. Usually a diagnosis is sought when the symptoms of malabsorption and malnutrition have been observed. There are two major tests available to physicians for the diagnosis of gluten intolerance:

  • Biopsy of the small intestine. This is considered the best test for diagnosing gluten intolerance because of its high degree of accuracy. The test involves a physician obtaining a sample of the intestinal lining through a procedure known as an esophagogastroduodenoscopy (EGD). The EGD procedure, a type of upper endoscopy, uses a small camera, inserted down the throat on a flexible tube, to navigate down to the intestinal lining and remove a small sample. The patient typically receives general anesthesia or a sedative. A pathologist will then examine the sample to check for characteristics that indicate gluten intolerance, such as a loss of villi (protrusions found on the lining of the small intestine that absorb nutrients into the bloodstream).

  • Antibody test. A blood test for the presence of certain antibodies – specifically, antibodies to endomysium (bands of connective tissue spread among muscular fibers) and transglutaminase (a substance that repairs injured or inflamed tissue). These antibodies form when the immune system reacts to the presence of substances it views as threatening. When certain specific antibodies are present in the bloodstream, an individual has a greater than 95 percent chance of having gluten intolerance.

Though not able to diagnose gluten intolerance directly, there are also several types of blood tests available for detecting the related malnutrition and vitamin deficiencies. These tests will usually show some type of a reduction in blood protein levels or iron-deficiency anemia in gluten-intolerant individuals.

Because gluten intolerance is a hereditary disease, the family members of an individual who has gluten intolerance may wish to be tested for the disease.

Because of recent research that has shown a close relationship between gluten intolerance and the development of osteoporosis, some physicians are screening patients diagnosed with osteoporosis for gluten intolerance as well. And people who are diagnosed with gluten intolerance may be screened for osteoporosis with a bone density test such as a DEXA scan, a type of x-ray.

Treatment and prevention

As with food allergies, treatment of gluten intolerance (celiac disease) is best achieved by completely removing gluten from the diet. If this is accomplished and maintained, gluten-intolerant individuals should see related symptoms subside.

In fact, maintaining a gluten-free diet eventually allows intestinal damage already caused by the disease to heal. This healing usually occurs in three to six months for younger people and after several years for older people. Young children who successfully implement a gluten-free diet often see positive changes in physical symptoms and behavior. Growth spurts at this point are not uncommon.

Maintaining a gluten-free diet is not easy. Gluten is found in many foods, and all types of wheat, barley and rye should be avoided. Because some patients also cannot tolerate oats, people with gluten intolerance should follow their physician’s or dietitian’s advice on whether or not to eat oats, according to the National Institutes of Health. Unfortunately, gluten is also frequently used in some seemingly unrelated products such as some lipsticks, postage stamps, medications and vitamins.

Individuals with gluten intolerance should consult their physician and learn which foods and products are dangerous. They must also learn to always read ingredient labels and ask questions about food preparation at restaurants. Individuals should be sure to learn any alternate names of dangerous substances.

Although a gluten-free diet has restrictions, there are a wide range of foods available to someone with gluten intolerance. More and more retail food stores are stocking their shelves with foods that are gluten-free. Foods such as meats, fish, poultry, (most) dairy products, unprocessed fruits and vegetables, beans, rice and potatoes are all safe. Gluten-free flours, such as those made from rice, soy, corn or potato, are available as alternatives. In addition, foods made from cornmeal are safe. There are also gluten-free cookies, cereals, breads and pastas.

In 2006 the U.S. Food and Drug Administration (FDA) began requiring food manufacturers to list food allergens on their product labels. Although labels are becoming easier to read, people buying gluten-free products must be aware that manufacturers can change the ingredients of a product at any time. For this reason, people should continue to read the labels on all products, including those they buy frequently. In addition, most companies offer a customer service line to answer questions regarding their products.

The FDA has proposed a gluten-free labeling rule that covers wheat, rye, barley and crossbred hybrids of these grains but not oats.

An individual may accidentally eat gluten after beginning a gluten-free diet without noticing any symptoms. However, this does not mean that no harm has been done. Any gluten ingested by a gluten-intolerant person will damage the small intestine. It is very dangerous to practice an on-and-off gluten diet. Strict adherence to a gluten-free diet is essential.

When traveling, people on a gluten-free diet may benefit from packing several snack bars to avoid having to buy food that is not safe for consumption.

Aside from maintaining a gluten-free diet, individuals may also need to address any nutritional deficiencies that developed as a result of their condition. A physician can recommend specific vitamin and mineral supplements to counteract these deficiencies.

Patients who fail to respond to a gluten-free diet should seek help from their physician. Though the problem is likely a relatively minor issue (such as the unknowing ingestion of gluten), failure to respond may indicate an advanced form of gluten intolerance (e.g., refractory celiac disease) or other conditions.

Women who have a gluten intolerance while pregnant risk harming their unborn fetus or delivering prematurely if their intolerance is not properly controlled. Any woman with a gluten intolerance who plans to become pregnant or learns she is already pregnant should discuss her condition with a physician.

Questions for your doctor

Preparing questions in advance can help patients have more meaningful discussions with their physicians regarding their conditions. Patients may wish to ask their doctor the following questions about gluten intolerance (celiac disease):

  1. What tests will you use to determine if I have gluten intolerance?

  2. What risks do I face as a result of having gluten intolerance? Should I have periodic screening tests for these conditions?

  3. What treatment options are available to me?

  4. Do I need to follow a gluten-free diet for the rest of my life?

  5. What types of food should I avoid? Do I need to avoid any other products that may contain gluten, such as certain lipsticks, adhesives or vitamin pills?

  6. What will happen to me if I do not adhere to a gluten-free diet?

  7. If I accidentally eat something that has gluten, what should I do? Will I need to go to the hospital?

  8. What terms should I look for on food labels?

  9. Do I need to take a multivitamin or other supplement?

  10. Does the fact that I suffer from gluten intolerance increase the odds that my children will have it?
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