Gluten sensitive enteropathy (Celiac Disease) and Gluten Sensitivity (non-celiac gluten sensitivity)
Gluten Associated Diseases
Gluten intolerance or gluten sensitive enteropathy refers to a group of disorders that are associated with the consumption of foods containing gluten (Gluten Associated Diseases – GAD). Gluten is a protein present in wheat, barley, rye (or in foods prepared from these grains), and is known to precipitate the disease/symptoms in susceptible individuals. Symptoms can vary significantly from one individual to another and may include abdominal pain, diarrhea, gas, bloating, vomiting, nausea, skin irritation, weight-loss, anemia, fatigue, weakness, joint pain, muscle-cramps, headaches, neurological symptoms. There is significant improvement in health with a strict gluten-free diet.
Celiac disease is one of the disorders associated with consumption of gluten. It is a genetically inherited autoimmune condition. Dietary gluten appears to be an important trigger that initiates inflammation and destruction of the surface of the small GI tract. Therefore, there is a decreased ability to absorb nutrients from food, possibly multi-organ effects from malabsorption, and other consequences. Celiac disease is estimated to be present in about 1-2% of the North American population.
Non-Celiac Gluten Sensitivity
Non-Celiac gluten sensitivity is now recognized as a distinct clinical entity that is separate from Celiac Disease. The incidence of non-celiac gluten sensitivity (NCGS) is significantly higher than that of Celiac Disease, and estimated to be more than 5% of the general population in North America. Affected individuals experience adverse reactions to gluten and may experience symptoms similar to those observed in celiac disease. Unlike celiac disease, damage to the small intestine has not been observed. However, it is important to recognize that there are a number of endocrine and nervous system conditions which appear to be associated with gluten intolerance, including unexplained anemia, fatigue, infertility, peripheral neuropathy, depression, weight loss, osteoporosis, type I diabetes, and thyroid disease. Gluten-free diet generally results in diminution of symptoms and improvement in health.
Assessment and Testing
For celiac disease screening, the initial testing is performed with a blood test known as anti-Tissue Transglutaminase IgA (TTG-IgA). During the active phase of the disease, TTG-IgA levels are usually elevated. It is important to be on a gluten containing diet in preparing for this test (for at least 2 weeks prior to testing).
About 60% of the non-celiac gluten-sensitive individuals have elevated blood levels of antibodies to gliadin* (IgA, IgG or both); yet blood levels of TTG-IgA are not elevated. Diagnosis is established by ruling out possibility of celiac disease, wheat allergy, and other conditions or factors (digestive disorders, toxicity etc), and a gluten elimination diet. With elevated gliadin antibodies (i.e. food IgG sensitivity testing – wheat, barley, rye and/or gliadin, or gliadin IgA), testing for TTG-IgA and wheat IgE should also be performed to exclude possibility of Celiac Disease or wheat allergy; followed by a gluten-free diet for assessment of symptoms. Non-Celiac gluten sensitive subjects have negative results for TTG-IgA and wheat IgE with improvement in health while on a gluten elimination diet (gluten-free diet).
*Gliadin is a component of gluten and the primary active portion involved in the disease process/symptoms.It is very important that gluten/gliadin containing foods be consumed as part of the food challenge in preparationfor IgG food sensitivity testing, IgE, or gliadin IgA testing. Only foods that precipitate serious (IgE mediated) symptoms should be avoided for the food challenge.