Celiac disease affects 1 in 133 Americans, with a greater prevalence seen in those with first generation relatives with the condition. The disease manifests itself with intolerance for gluten. Gastrointestinal discomfort, weight loss and abdominal bloating are common symptoms. Determining the gluten index in foods can help celiac disease patients make safe food choices. It is essential because there are so many hidden sources of gluten in food additives. Testing takes the guesswork out of living a gluten-free lifestyle.
What Is Gluten?
Gluten intolerance is caused by an abnormal autoimmune response to a gluten protein called gliadin. Gluten gives wheat dough its elasticity. It is also found in rye and barley. When a gluten-sensitive person ingests a food containing gluten, the body produces antibodies which attack it, not unlike the reaction to a bacterial infection. The problem is that the immune response also results in the destruction of the villi of the small intestine. The villi are small projections of tissue which increase the absorption surface area. A gluten-intolerant individual typically suffers from nutrient deficiencies because of the body's reduced capacity to absorb them.
The gluten content of food must be determined by laboratory testing. A 2006 U.S. Department of Agriculture study reviewed different methods of testing grains for gluten, finding that using flour for a testing sample rather than ground meal produced the best results. Methods for assessing gluten content vary depending upon the type of product tested and the intended end use.
The ability for manufacturers to test for gluten is essential because it is so widespread in foods and beverages. It may seem obvious to forgo eating whole wheat bread if you are gluten intolerant. However, gluten is also found in products such as soy sauce, pasta and couscous. Yet it also can be used as a base in ingredients such as modified food starch, maltodextrin and natural flavorings. Determining the gluten index of foods and beverages allows businesses to comply with U.S. Food and Drug Administration standards for voluntarily labeling products "gluten-free." However, it is not required on all processed products.
The FDA has guidelines which provide specific guidelines for foods labeled "gluten-free." Based on current science and technology, the FDA uses a gluten concentration of 20 parts per million (ppm) as the threshold for determining if a product can be labeled gluten-free. Products are not labeled with a specific gluten index number because current technology is not precise enough. Rather, labeling uses the 20 ppm figure for determining product content. Products are either gluten-free if they fall below 20 ppm or not gluten-free if the gluten concentration is higher than 20 ppm.
- "Archives of Internal Medicine"; Prevalence of Celiac Disease in At-Risk and Not-At-Risk Groups in the United States; A. Fassano, et al.; February 2003
- "Principles of Anatomy and Physiology"; G. Tortora et al; 2005
- "Cereal Chemistry"; Comparison of Methods for Gluten Strength Assessment; C. Gaines, et al.; May/June 2006
- Celiac: Unsafe Gluten-Free Food List (Unsafe Ingredients)
- U.S. Food and Drug Administration; Questions and Answers on the Gluten-Free Labeling Proposed Rule; Jan. 23, 2007