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- Tips on developing a gluten-free diet, lists of gluten-free products and recipes from our Food, Nutrition and Health pages
Celiac disease is also known as celiac sprue, non-tropical sprue, or gluten-sensitive enteropathy. This illness is a malabsorption syndrome occurring in sensitive individuals upon the consumption of wheat, rye, barley, and related grains such as kamut, triticale, durum wheat or semolina, club wheat emmer, einkorn, and farro. Celiac disease serves as the best example of delayed hypersensitivity reactions associated with foods.
Celiac disease differs from IgE-mediated food allergies in several important respects. Celiac disease is NOT mediated by allergen-specific antibodies including IgE. Celiac disease is a delayed hypersensitivity reaction where symptoms develop 48-72 hours after ingestion of the offending food which is in contrast to IgE-mediated food allergies where symptoms develop rather quickly (within minutes to hours after ingestion of the offending food).
Celiac disease does share some common features with IgE-mediated food allergies. Celiac disease is immunologically mediated, though not by antibodies. Celiac disease does affect only certain individuals in the population. And, most importantly, individuals with celiac disease must avoid the causative protein fraction, gluten, in their diets. See 5 gluten-free recipes below.
Celiac disease is a cell-mediated, localized inflammatory reaction occurring in the intestinal tract upon provocation with ingested gluten. The inflammatory reaction results in a so-called ‘flat lesion’ in the gut. The cell-mediated immunological reaction in the small intestine results in intestinal damage characterized by villous atrophy along with crypt hyperplasia, lymphoid infiltration of the epithelium, and edema of the lamina propria. Once the damage appears, the absorptive function of the epithelium is impaired; increased fluid secretion into the intestinal lumen and enhanced permeability of the epithelium are also observed. Both digestion and absorption are impaired. The mucosal enzymes necessary for digestion and absorption are altered in the damaged cells. The absorptive cells are functionally compromised. The mucosal damage leads to nutrient malabsorption and affected individuals (if untreated) display features of nutrient deficiencies. It appears as though a defect in mucosal processing of gliadin (the prolamin protein found in wheat) in celiac patients provokes the generation of toxic peptides that contribute to the abnormal immunologic response and the subsequent inflammatory reaction.
Additional information on celiac disease, including tips on developing a gluten-free diet and lists of gluten-free products and recipes, can be found on our Food, Nutrition and Health pages. The Celiac Sprue Association website and the Canadian Celiac Association website also provide more resources.
The symptoms of celiac disease are those associated with a severe malabsorption syndrome characterized by diarrhea, bloating, weight loss, anemia, bone pain, chronic fatigue, weakness, various nutritional deficiencies, muscle cramps, and, in children, failure to thrive. Celiac patients are also more likely to develop other autoimmune diseases.
- Prevalence of Celiac Disease
The prevalence of celiac disease in the U.S. is estimated at 1 in every 133 individuals. This estimate remains somewhat uncertain because celiac disease can on occasion be rather difficult to diagnose.
- Management of Celiac Disease
Celiac disease is treated by implementation of a gluten avoidance diet. Those with celiac disease attempt to avoid all sources of wheat, rye, barley, and related grains including a wide variety of common food ingredients derived from these grains.
The symptoms of celiac disease are those associated with a severe malabsorption syndrome characterized by diarrhea, bloating, weight loss, anemia, bone pain, chronic fatigue, weakness, various nutritional deficiencies, muscle cramps, and, in children, failure to thrive.
The risk of death is quite low, but untreated celiac disease is associated with considerable discomfort in many celiac sufferers. Also, individuals suffering from celiac disease for long periods are at increased risk for development of T cell lymphomas.
Celiac patients also are more likely than others to have various other diseases especially diseases of an autoimmune nature including dermatitis herpetiformis, thyroid diseases, Addison’s disease, pernicious anemia, autoimmune thrombocytopenia, sarcoidosis, insulin-dependent diabetes mellitus, IgA nephropathy, and Down’s syndrome.
The most severely affected individuals suffer rather noteworthy symptoms until placed on an avoidance diet. But, many affected individuals have less severe symptoms making diagnosis much more challenging.
For example, if anemia is the foremost symptoms, as it is in some celiac sufferers, there are numerous potential causative factors for anemia which often delays the diagnosis of celiac disease.
Some, perhaps many, individuals suffer from latent (or silent) celiac disease. These individuals experience no noticeable adverse reactions upon ingestion of gluten but have anti-endomysial antibodies or other diagnostic features consistent with celiac disease. The likelihood that these individuals will later develop symptomatic celiac disease is unknown.
The prevalence of celiac disease remains somewhat uncertain for several reasons. First, the diagnosis of celiac disease can on occasion be rather difficult. Celiac disease appears to be latent or sub-clinical in some individuals with symptoms only appearing occasionally. Furthermore, intestinal biopsies are needed to observe the ‘flat lesion’ in untreated individuals, an expensive and invasive procedure. Biopsies have been replaced by blood tests for certain antibodies that are associated with celiac disease (not causative but associated). These antibodies include the anti-endomysial antibody and the tissue transglutaminase antibody. The availability of these diagnostic tests has allowed the identification of individuals with latent celiac disease who do not have the ‘flat lesion’.
On this diagnostic basis, the prevalence of celiac disease in the U.S. is estimated at 1 in every 133 individuals. However, on the basis of diagnostic biopsies, the estimated prevalence is much lower at somewhere between 1 per 1000 or 1 per 2000 individuals.
The prolamin protein fractions of wheat, rye, and barley are the causative factors in celiac disease. In wheat, the prolamin fraction is called gliadin, while it is called secalin in rye and hordein in barley. However, the prolamin proteins from these related grains are highly homologous and cross-reactive. Gliadin is the alcohol-soluble protein of the prolamin fraction and is the principal causative factor in the elicitation of celiac disease. However, the glutenin, or alcohol-insoluble fraction, is also likely involved. Since the prolamins are the major storage proteins in these grains, all varieties of wheat, rye, and barley are considered hazardous for celiac sufferers. The level of these proteins in wheat, rye, and barley is rather high.
Celiac disease is treated by implementation of a gluten avoidance diet. Those with celiac disease attempt to avoid all sources of wheat, rye, barley, and related grains including a wide variety of common food ingredients derived from these grains. The need to avoid ingredients that do not contain protein from the implicated grains is somewhat debatable, but widely practiced. Most celiac sufferers also avoid oats, and that is likely wise considering the frequent contamination of oats with wheat from shared farms, harvesting equipment and storage facilities. Celiac sufferers benefit from the commercial availability of gluten-free foods. The availability and diversity of gluten-free foods has expanded considerably in recent years. The popularity of gluten-free foods is driving this expansion. Clearly, gluten-free foods are being purchased (in the U.S. at least) by numerous consumers who do not have a diagnosis of celiac disease.
The Codex Alimentarius Commission has established a guideline definition for gluten-free foods: these foods should contain no more that 20 ppm gluten. Many countries around the world have adopted the Codex guidance and use <20 ppm as the definition of gluten-free. However, some countries may not have yet adopted the 20 ppm guideline and may still use the former Codex guideline of <200 ppm gluten. Most notably, no definition for gluten-free has ever been adopted in the U.S. However, the U.S. Food & Drug Administration is considering defining gluten-free as below 20 ppm; this proposal has not yet been finalized. The minimal eliciting dose for wheat, rye, barley, and related grains among celiac sufferers is unknown and is likely variable between affected individuals. Many individuals with celiac disease go to great lengths to avoid all sources of wheat, rye, barley, and triticale. While this has not been conclusively proven, a few isolated studies have concluded that levels of 10 mg of gliadin per day will be tolerated by most patients with celiac disease.