I recently discovered after doing some research these facts on Gluten. It is the summary of a paper on Individuals with celiac disease. These individuals are generally are advised to follow a lifelong gluten-free diet and avoid consumption of the prolamins gliadin (wheat), secalin (rye), and hordein (barley).
Barley has a similar protein called hordein, and rye has one called secalin. These both contain the same amino acid sequences that cause problems in people with gluten sensitivity. These three proteins: gliadin, hordein and secalin, are in a category of proteins called prolamins that are present in all the grains of the grass family. The family also includes oats, corn, rice, millet and others. In oats the prolamin is called avenin. Avenin may cause problems in some people with gluten sensitivities because avenin contains some of the same problematic amino acids as the prolamins in wheat, rye and barley–just in lower amounts. The other grains don’t contain those sequences.
Although the designation of the diet as gluten-free may imply that the diet contains zero gluten, this is not necessarily true. In some countries (i.e. United States, Canada), the gluten-free diet is completely devoid of gluten and is based on foods such as rice and corn that are naturally gluten-free.
In others (i.e. Scandinavia, United Kingdom), the gluten-free diet may include foods such as wheat starch that have been rendered gluten-free but nonetheless contain small amounts of toxic prolamins.
The discrepancy in the use of foods rendered gluten-free exists because the amount of toxic prolamins that individuals with celiac disease may consume without damaging the mucosa of the small intestine is unknown. Minimal research has been conducted on the toxicity of foods rendered gluten-free, and there are no definitive data about whether the small amount of prolamin found in these products is safe to consume.