Gluten (from Latin gluten, "glue") is a protein composite found in wheat and related grains, including barley and rye. Gluten gives elasticity to dough, helping it rise and keep its shape and often gives the final product a chewy texture. Gluten is used in cosmetics, hair products, and other dermatological preparations.
Gluten is the composite of a gliadin and a glutenin, which is conjoined with starch in the endosperm of various grass-related grains. The prolamin and glutelin from wheat (gliadin, which is alcohol-soluble, and glutenin, which is only soluble in dilute acids or alkalis) constitute about 80% of the protein contained in wheat fruit. Being insoluble in water, they can be purified by washing away the associated starch. Worldwide, gluten is a source of protein, both in foods prepared directly from sources containing it, and as an additive to foods otherwise low in protein.
The fruit of most flowering plants have endosperms with stored protein to nourish embryonic plants during germination. True gluten, with gliadin and glutenin, is limited to certain members of the grass family. The stored proteins of maize and rice are sometimes called glutens, but their proteins differ from true gluten.
About 1 in 133 people in developed nations have intolerance to gluten. Gluten sensitivity is classified as intolerance, not an allergy.
Gluten refers to the proteins found in wheat endosperm (a type of tissue produced in seeds that's ground to make flour). Gluten both nourishes plant embryos during germination and later affects the elasticity of dough, which in turn affects the chewiness of baked wheat products.
Gluten is actually composed of two different proteins: gliadin (a prolamin protein) and glutenin (a glutelin protein).
Though "true gluten" is sometimes defined as being specific to wheat, gluten is often said to be part of other cereal grains — including rye, barley and various crossbreeds — because these grains also contain protein composites made from prolamins and glutelins.
Why is gluten bad?
Gluten isn't necessarily bad, but some people are gluten-intolerant, meaning their bodies produce an abnormal immune response when it breaks down gluten from wheat and related grains during digestion.
The most well-known form of gluten intolerance is celiac disease, which affects one in every 141 people in the United States, according to the National Institutes of Health. When someone with celiac disease consumes gluten, it triggers an immune response that damages their intestines, preventing them from absorbing vital nutrients.
Wheat allergy is a rare type of gluten intolerance — it's a classic food allergy marked by skin, respiratory or gastrointestinal reactions to wheat allergens.
Recently, scientists have become aware of another potential form of intolerance called nonceliac gluten sensitivity. After consuming gluten, patients with gluten sensitivity may experience many celiac disease symptoms, such as diarrhea, fatigue and joint pain, but don't appear to have damaged intestines.
In cases of gluten intolerance, doctors typically recommend a gluten-free diet. Patients must avoid eating any foods and ingredients that contains gluten, including bread, beer, french fries, pasta, salad dressing, soy sauce and even some soups (unless otherwise marked as "gluten-free").
In recent years, many people without gluten intolerance have taken up gluten-free diets. Experts worry, however, that going on these diets without explicitly needing to could be detrimental to a person's health, as gluten-free foods are often nutrient-deficient.