Several grains and starch sources are considered acceptable for a gluten-free diet. The most frequently used are corn, potatoes, rice, and tapioca (derived from cassava). Other grains and starch sources generally considered suitable for gluten-free diets include amaranth, arrowroot, millet, montina, lupin, quinoa, sorghum (jowar), sweet potato, taro, teff, chia seed, and yam. Various types of bean, soybean, and nut flours are sometimes used in gluten-free products to add protein and dietary fiber. In spite of its name, buckwheat is not related to wheat; pure buckwheat is considered acceptable for a gluten-free diet, although many commercial buckwheat products are actually mixtures of wheat and buckwheat flours, and thus not acceptable. Gram flour, derived from chickpeas, is also gluten-free (this is not the same as Graham flour made from wheat).
Gluten is also used in foods in some unexpected ways, for example as a stabilizing agent or thickener in products like ice-cream and ketchup.
People wishing to follow a completely gluten free diet must also take into consideration the ingredients of any over-the-counter or prescription medications and vitamins. Also, cosmetics such as lipstick, lip balms, and lip gloss may contain gluten and need to be investigated before use.
Cross-contamination issues
Special care is necessary when checking product ingredient lists since gluten comes in many forms: vegetable proteins and starch, modified food starch (when derived from wheat instead of maize), malt flavoring, and glucose syrup. Many ingredients contain wheat or barley derivatives. Maltodextrin, formerly thought to contain gluten, is now generally considered gluten free.
Although many foods contain gluten, it is not always included in ingredients lists. This lack of inclusion is because gluten is not used in the formulation of the product, but in the preparation (or manufacturing) of listed ingredients. One example is the dusting of the conveyor belts in the production facilities with gluten products to prevent the foods from sticking during processing.
Controversy over oats
The suitability of oats in the gluten-free diet is still somewhat controversial. Some research suggests that oats in themselves are gluten free, but that they are virtually always contaminated by other grains during distribution or processing. However, recent research indicated that a protein naturally found in oats (avenin) possessed peptide sequences closely resembling wheat gluten and caused mucosal inflammation in significant numbers of celiac disease sufferers. Some examination results show that even oats which are not contaminated with wheat particles, are nonetheless dangerous to about 10 percent of coeliacs, while not very harmful to the majority. Such oats are generally considered risky for coeliac children to eat, but two studies show that they are completely safe for coeliac adults to eat, even over a period of five years. Given this conflicting information, excluding oats appears to be the only risk-free practice for celiac disease sufferers of all ages. However, medically approved guidelines exist for those coeliacs who do wish to introduce oats into their diet.
Unless manufactured in a dedicated facility and under gluten-free practices, all cereal grains, including oats, can be cross-contaminated with gluten. Grains become contaminated with gluten by sharing the same farm, truck, mill, or bagging facility as wheat and other gluten-containing grains. Therefore, removing all flours and grains from the diet may be the only way to guarantee a complete absence of gluten in the diet.
Accuracy of "gluten-free" labels
Sausages may contain gluten via fillers or binders such as Butcher's Rusk
Standards for "gluten-free" labelling have been set up by the "Codex Alimentarius"; however, these regulations do not apply to "foods which in their normal form do not contain gluten".
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).
Australian standards reserve the "gluten free" label for foods with less than 5 parts per million of gluten, as this is the smallest amount currently detectable. In the processing of gluten-containing grains, gluten is removed (shown in the processing flow below)
Wheat Flour (80,000ppm) > Wheat Starch (200ppm) > Dextrin > Maltodextrin > Glucose Syrup (<5ppm) > Dextrose > Caramel Color
Since ordinary wheat flour contains approximately 12% gluten,[12] 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; it also excludes gravies, custards, soups and sauces thickened with wheat, rye, barley or other gluten-containing flour. Many countries do not require labeling of gluten containing products, but in several countries (especially Australia and the European Union) new product labeling standards are enforcing the labeling of gluten-containing ingredients. Various gluten-free bakery and pasta products are available from specialty retailers.
In the United States, gluten may not be listed on the labels of certain foods because the U.S. Food and Drug Administration has classified gluten as GRAS (Generally Recognized As Safe).[13] Requirements for proper labeling are being formulated by the USDA. It is currently up to the manufacturers of "gluten free" food items to guarantee such a claim. "A final rule that defines the term gluten-free and identifies the criteria that would enable the food industry to use that term" was scheduled to be released by the FDA on August 2, 2008.
Many so-called gluten free products have been found to have been contaminated with gluten such as chicken bouillon, corn cereal, and caramel ice cream topping. For example, in a investigation reported by the Chicago Tribune on November 21, 2008, Wellshire Farms chicken nuggets labeled "gluten-free" were purchased and samples were sent to a food allergy lab at the University of Nebraska. Results of the testing indicated gluten was present in levels exceeding 2,000 ppm. After the article was published, the products were continued to be sold. However, after receiving customer inquiries, Whole Foods Market removed the product from their shelves over a month later. Wellshire Farms has since replaced the batter used in their chicken nuggets.
In the United Kingdom, only cereals currently need to be labeled, while other products are voluntary. For example, most British sausages contain Butcher's Rusk, a grain-derived food additive. Furthermore, while UK companies selling food prepared on their own premises are given guidance by the Food Standards Agency, they are not required to meet any labeling requirements.
Lastly, some non-foodstuffs such as medications and vitamin supplements, especially those in tablet form, may contain gluten as an excipient or binding agent. People with gluten intolerances may therefore require specialist compounding of their medication.
Alcoholic beverages
Several celiac groups report that according to the American Dietetic Association's "Manual of Clinical Dietetics" many types of alcoholic beverages are considered gluten free, provided no colourings or other additives have been added as these ingredients may contain gluten. Although most forms of whiskey are distilled from a mash that includes grains that contain gluten, distillation removes any proteins present in the mash, including gluten. Although up to 49% of the mash for Bourbon and up to 20% of the mash for corn whiskey may be made up of wheat, or rye, all-corn Bourbons and corn whiskeys do exist, and are generally labeled as such. Spirits made without any grain such as brandy, wine, mead, cider, sherry, port, rum, tequila and vermouth do not contain gluten, although some vineyards use a flour paste to caulk the oak barrels in which wine is aged, so some celiacs may wish to exercise caution. Liqueurs and pre-mixed drinks should be examined carefully for gluten-derived ingredients.
It should be noted that, while many spirits were traditionally made without grain, such as tequila, rum and vodka, today they are more commonly made with barley, wheat or rye (instead of agave, sugar or potatoes, etcetera). Often, only high-end specialty alcoholic brands are made with what are considered the traditional ingredients. In addition, many people diagnosed with celiac disease still experience symptoms when drinking distilled alcoholic beverages. Therefore, it is advised that a person with celiac disease check with a manufacturer about the ingredients that have been used in a hard liquor, and to proceed with caution if choosing to drink a liquor that is made with wheat, barley, oats or rye.
Almost all beers are brewed with malted barley or wheat and will contain gluten. Sorghum and buckwheat-based gluten-free beers are available, but remain very much a specialty product. Some low-gluten beers are also available, however there is disagreement over the use of gluten products in brewed beverages: Some brewers argue that the proteins from such grains as barley or wheat are converted into amino acids during the brewing process and are therefore gluten-free, however there is evidence that this claim is false.