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.