Gluten-free diet
A gluten-free diet is a diet completely free of ingredients derived from gluten containing cereals: wheat, barley, rye, kamut, spelt, and triticale. The suitability of oats in the gluten-free diet is uncertain; consequently most persons who have been medically directed to follow a gluten-free diet also avoid oats. This diet must be strictly followed by sufferers of celiac disease and dermatitis herpetiformis. Some medical practitioners also believe the gluten-free diet may be helpful for persons with multiple sclerosis and other autoimmune disorders, but this has not yet been conclusively proven through medical studies.
Several grains and starches are considered acceptable for a gluten-free diet. The most frequently used are corn (maize), potatoes, rice, and tapioca (also called manioc or cassava). Other grains and starches generally considered suitable for gluten-free diets include amaranth, arrowroot, millet, montina, lupine, quinoa, sorghum (jowar), sweet potato, taro, tef, and yam. Various types of bean, soybean, and nut flours are sometimes used in gluten-free products to add protein and fiber. In spite of its name, buckwheat is not related to wheat; pure buckwheat is considered acceptable for a gluten-free diet (many commercial buckwheat products are actually mixtures of wheat and buckwheat flours, and thus not acceptable).
Special care must be taken when checking ingredients lists as gluten may come in forms such as vegetable proteins and starch, modified food starch (when derived from wheat instead of maize), maltodextrin, malt flavoring, and glucose syrup. Many common ingredients contain wheat or barley derivatives.
Many foods will contain gluten, but not be indicated on the ingredients, because they are not in the formulation of the product, but in the preparation of it. One example of this is the dusting of the conveyor belts in the production facilities to prevent the foods from sticking during processing. The food itself might not contain gluten, but there is gluten in the ingested product.
The legal definition of the phrase "gluten-free" varies from country to country. Current research suggests that for persons with celiac disease the maximum safe level of gluten in a finished product is probably less than 0.02% (200 parts per million) and possibly as little as 0.002% (20 parts per million). Since ordinary wheat flour contains approximately 12% gluten, even a tiny amount of wheat flour can cross-contaminate a gluten-free product. Therefore, considerable care must be taken to prevent cross-contamination in both commercial and home food preparation.
This diet rules out all ordinary breads, pastas, and many convenience foods. Many countries do not require labelling of gluten containing products, but in several countries new product labelling standards are enforcing the labelling of gluten-containing ingredients. Various gluten-free bakery and pasta products are available from specialty retailers.