What Is Gliadin?

Gliadin is one of two types of proteins, along with glutenin–that are the components of the gluten in wheat. It is the part of the gluten that contains specific amino acids sequences that people react to if they have Celiac Disease or another form of gluten sensitivity, except for some gluten allergies.

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.
Find out more: Are Oats Gluten Free?

Role In Celiac Disease

In gluten sensitive people the presence of gliadin, secalin, or hordein, and sometimes avenin, in the small intestine causes the immune system to produce antibodies. These may lead to damage of the intestine if the conditions are such that Celiac Disease is the problem.

These antibodies are useful in pre-screening for Celiac Disease, but only indicate that there is some gluten sensitivity. It’s not necessarily Celiac Disease. That’s why further testing is necessary to confirm Celiac Disease, usually a biopsy. For more info see What is Celiac Disease?
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Role In Gluten Sensitivity Other Than Celiac Disease

Gliadin and its related proteins secalin and hordein, and possibly avenin, have several forms. Some trigger Celiac disease as mentioned above, and some cause other types of gluten sensitivity such as gluten allergies and others. In these cases screening for Celiac disease may have found that antibodies are present, but Celiac Disease was not confirmed with a biopsy.

Many of these sensitivities are called Idiopathic–meaning they really don’t know the cause. But if antibodies indicating a problem are present, it may be enough to get your doctor to pay attention and help you find out what is wrong. It may be a different type of gluten sensitivity.
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Nutritional Supplements

Gliadin is sometimes used to protect enzymes in supplements from stomach acids, which would break them down too soon. This is yet another form of a hidden problem for gluten sensitive people.
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