Gluten Flour
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Gluten is a
structural protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, respon ...
naturally found in certain
cereal grains A cereal is a grass cultivated for its edible grain. Cereals are the world's largest crops, and are therefore staple foods. They include rice, wheat, rye, oats, barley, millet, and maize (Corn). Edible grains from other plant families, such ...
. The term ''gluten'' usually refers to the elastic network of a wheat grain's proteins,
gliadin Gliadin (a type of prolamin) is a class of proteins present in wheat and several other cereals within the grass genus ''Triticum''. Gliadins, which are a component of gluten, are essential for giving bread the ability to rise properly during ba ...
and
glutenin Glutenin (a type of glutelin) is a major protein within wheat flour, making up 47% of the total protein content. The glutenins are protein aggregates of high- molecular-mass (HMW) and low-molecular-mass (LMW) subunits with molar masses from ab ...
primarily, that forms readily with the addition of water and often
kneading In cooking (and more specifically baking), kneading is a process in the making of bread or dough, used to mix the ingredients and add strength to the final product. It allows the process of baking to be shortened by developing the gluten more qu ...
in the case of bread dough. The types of grains that contain gluten include all species of
wheat Wheat is a group of wild and crop domestication, domesticated Poaceae, grasses of the genus ''Triticum'' (). They are Agriculture, cultivated for their cereal grains, which are staple foods around the world. Well-known Taxonomy of wheat, whe ...
(
common wheat Common wheat (''Triticum aestivum''), also known as bread wheat, is a cultivated wheat species. About 95% of wheat produced worldwide is common wheat; it is the most widely grown of all crops and the cereal with the highest monetary yield. Ta ...
,
durum Durum wheat (), also called pasta wheat or macaroni wheat (''Triticum durum'' or ''Triticum turgidum'' subsp. ''durum''), is a tetraploid species of wheat. It is the second most cultivated species of wheat after common wheat, although it repres ...
,
spelt Spelt (''Triticum spelta''), also known as dinkel wheat is a species of wheat. It is a relict crop, eaten in Central Europe and northern Spain. It is high in protein and may be considered a health food. Spelt was cultivated from the Neolit ...
,
khorasan KhorasanDabeersiaghi, Commentary on Safarnâma-e Nâsir Khusraw, 6th Ed. Tehran, Zavvâr: 1375 (Solar Hijri Calendar) 235–236 (; , ) is a historical eastern region in the Iranian Plateau in West and Central Asia that encompasses western and no ...
,
emmer Emmer is a hybrid species of wheat, producing edible seeds that have been used as food since ancient times. The domesticated types are ''Triticum turgidum'' subsp. ''dicoccum'' and ''T. t. ''conv.'' durum''. The wild plant is called ''T. t.'' s ...
, and
einkorn Einkorn wheat (from German ''Einkorn'', literally "single grain") can refer to either a wild species of wheat (''Triticum'') or a domesticated form of wheat. The wild form is ''T. boeoticum'' (syn. ''T. m.'' subsp. ''boeoticum''), and the domes ...
), and
barley Barley (), a member of the grass family, is a major cereal grain grown in temperate climates globally. It was one of the first cultivated grains; it was domesticated in the Fertile Crescent around 9000 BC, giving it nonshattering spikele ...
,
rye Rye (''Secale cereale'') is a grass grown extensively as a grain, a cover crop and a forage crop. It is grown principally in an area from Eastern and Northern Europe into Russia. It is much more tolerant of cold weather and poor soil than o ...
, and some cultivars of
oat The oat (''Avena sativa''), sometimes called the common oat, is a species of cereal grain grown for its seed, which is known by the same name (usually in the plural). Oats appear to have been domesticated as a secondary crop, as their seeds ...
; moreover, cross hybrids of any of these cereal grains also contain gluten, e.g.
triticale Triticale (; × ''Triticosecale'') is a hybrid of wheat (''Triticum'') and rye (''Secale'') first bred in laboratories during the late 19th century in Scotland and Germany. Commercially available triticale is almost always a second-generation ...
. Gluten makes up 75–85% of the total protein in
bread wheat Common wheat (''Triticum aestivum''), also known as bread wheat, is a cultivated wheat species. About 95% of wheat produced worldwide is common wheat; it is the most widely grown of all crops and the cereal with the highest monetary yield. Ta ...
. Glutens, especially
Triticeae glutens Gluten is the seed storage protein in mature wheat seeds (and in the seeds of closely related species). It is the sticky substance in bread wheat which allows dough to rise and retain its shape during baking. The same, or very similar, proteins ...
, have unique
viscoelastic In materials science and continuum mechanics, viscoelasticity is the property of materials that exhibit both Viscosity, viscous and Elasticity (physics), elastic characteristics when undergoing deformation (engineering), deformation. Viscous mate ...
and
adhesive Adhesive, also known as glue, cement, mucilage, or paste, is any non-metallic substance applied to one or both surfaces of two separate items that binds them together and resists their separation. The use of adhesives offers certain advantage ...
properties, which give
dough Dough is a malleable, sometimes elastic paste made from flour (which itself is made from grains or from leguminous or chestnut crops). Dough is typically made by mixing flour with a small amount of water or other liquid and sometimes includes ...
its elasticity, helping it
rise Rise or RISE may refer to: Arts, entertainment, and media Fictional entities * '' Rise: The Vieneo Province'', an internet-based virtual world * Rise FM, a fictional radio station in the video game ''Grand Theft Auto 3'' * Rise Kujikawa, a vide ...
and keep its shape and often leaving the final product with a chewy texture. These properties, and its relatively low cost, make gluten valuable to both
food Food is any substance consumed by an organism for Nutrient, nutritional support. Food is usually of plant, animal, or Fungus, fungal origin and contains essential nutrients such as carbohydrates, fats, protein (nutrient), proteins, vitamins, ...
and non-food industries. Wheat gluten is composed of mainly two types of proteins: the
glutenin Glutenin (a type of glutelin) is a major protein within wheat flour, making up 47% of the total protein content. The glutenins are protein aggregates of high- molecular-mass (HMW) and low-molecular-mass (LMW) subunits with molar masses from ab ...
s and the
gliadin Gliadin (a type of prolamin) is a class of proteins present in wheat and several other cereals within the grass genus ''Triticum''. Gliadins, which are a component of gluten, are essential for giving bread the ability to rise properly during ba ...
s, which in turn can be divided into high molecular and low molecular glutenins and α/β, γ and Ω gliadins. Its homologous seed storage proteins, in barley, are referred to as
hordein Hordein is a prolamin glycoprotein, present in barley and some other cereals, together with gliadin and other glycoproteins (such as glutelins) coming under the general name of gluten. Hordeins are found in the endosperm where one of their functio ...
s, in rye,
secalin Secalin is a prolamin glycoprotein found in the grain rye, ''Secale cereale''. Secalin is one of the forms of gluten proteins that people with coeliac disease Coeliac disease (British English) or celiac disease (American English) is a long-te ...
s, and in oats,
avenin The oat (''Avena sativa''), sometimes called the common oat, is a species of cereal grain grown for its seed, which is known by the same name (usually in the plural). Oats appear to have been domesticated as a secondary crop, as their seeds ...
s. These protein classes are collectively referred to as "gluten". The storage proteins in other grains, such as
maize Maize (; ''Zea mays''), also known as corn in North American English, is a tall stout grass that produces cereal grain. It was domesticated by indigenous peoples in southern Mexico about 9,000 years ago from wild teosinte. Native American ...
(
zeins Zein ( ) is a class of prolamine protein found in maize. It is usually manufactured as a powder from corn gluten meal. Zein is one of the best understood plant proteins.Momany, Frank A.; Sessa, David J.; Lawton, John C.; Selling, Gordon W.; Ham ...
) and
rice Rice is a cereal grain and in its Domestication, domesticated form is the staple food of over half of the world's population, particularly in Asia and Africa. Rice is the seed of the grass species ''Oryza sativa'' (Asian rice)—or, much l ...
(
rice protein Rice protein is a vegan protein supplement, protein isolate made from rice. It is often used as an alternative to the more common whey and soy protein isolates. To make it, brown rice is treated with enzymes that cause carbohydrates to separate fro ...
), are sometimes called gluten, but they do not cause harmful effects in people with
celiac disease Coeliac disease (British English) or celiac disease (American English) is a long-term autoimmune disorder, primarily affecting the small intestine. Patients develop intolerance to gluten, which is present in foods such as wheat, rye, spel ...
. Gluten can trigger adverse, inflammatory,
immunological Immunology is a branch of biology and medicine that covers the study of immune systems in all organisms. Immunology charts, measures, and contextualizes the physiological functioning of the immune system in states of both health and disease ...
, and
autoimmune In immunology, autoimmunity is the system of immune responses of an organism against its own healthy cells, tissues and other normal body constituents. Any disease resulting from this type of immune response is termed an " autoimmune disease" ...
reactions in some people. The spectrum of gluten related disorders includes celiac disease in 1–2% of the general population,
non-celiac gluten sensitivity Non-celiac gluten sensitivity (NCGS) or gluten sensitivity is a controversial disorder which can cause both gastrointestinal and other problems. NCGS is included in the spectrum of gluten-related disorders. The definition and diagnostic criteria ...
in 0.5–13% of the general population, as well as
dermatitis herpetiformis Dermatitis herpetiformis (DH) is a chronic autoimmune blistering skin condition, characterised by intensely itchy blisters filled with a watery fluid. DH is a cutaneous manifestation of coeliac disease, although the exact causal mechanism is not ...
, gluten ataxia and other neurological disorders. These disorders are treated by a
gluten-free diet A gluten-free diet (GFD) is a nutritional plan that strictly excludes gluten, which is a mixture of prolamin proteins found in wheat (and all of its species and hybrids, such as spelt, kamut, and triticale), as well as barley, rye, and oats ...
.


Uses


Bread products

Gluten forms when glutenin molecules cross-link via
disulfide bond In chemistry, a disulfide (or disulphide in British English) is a compound containing a functional group or the anion. The linkage is also called an SS-bond or sometimes a disulfide bridge and usually derived from two thiol groups. In inor ...
s to form a submicroscopic network attached to gliadin, which contributes
viscosity Viscosity is a measure of a fluid's rate-dependent drag (physics), resistance to a change in shape or to movement of its neighboring portions relative to one another. For liquids, it corresponds to the informal concept of ''thickness''; for e ...
(thickness) and extensibility to the mix. If this dough is leavened with
yeast Yeasts are eukaryotic, single-celled microorganisms classified as members of the fungus kingdom (biology), kingdom. The first yeast originated hundreds of millions of years ago, and at least 1,500 species are currently recognized. They are est ...
,
fermentation Fermentation is a type of anaerobic metabolism which harnesses the redox potential of the reactants to make adenosine triphosphate (ATP) and organic end products. Organic molecules, such as glucose or other sugars, are catabolized and reduce ...
produces
carbon dioxide Carbon dioxide is a chemical compound with the chemical formula . It is made up of molecules that each have one carbon atom covalent bond, covalently double bonded to two oxygen atoms. It is found in a gas state at room temperature and at norma ...
bubbles, which, trapped by the gluten network, cause the dough to rise.
Baking Baking is a method of preparing food that uses dry heat, typically in an oven, but it can also be done in hot ashes, or on hot Baking stone, stones. Bread is the most commonly baked item, but many other types of food can also be baked. Heat is ...
coagulates the gluten, which, along with starch, stabilizes the shape of the final product. Gluten content has been implicated as a factor in the
staling Staling, or "going stale", is a chemical and physical process in bread and similar foods that reduces their palatability. Stale bread is dry and hard, making it less suitable for different culinary uses than fresh bread. Countermeasures and desta ...
of bread, possibly because it binds water through hydration. The formation of gluten affects the texture of the baked goods. Gluten's attainable elasticity is proportional to its content of glutenins with low molecular weights, as this portion contains the preponderance of the
sulfur Sulfur ( American spelling and the preferred IUPAC name) or sulphur ( Commonwealth spelling) is a chemical element; it has symbol S and atomic number 16. It is abundant, multivalent and nonmetallic. Under normal conditions, sulfur atoms ...
atoms responsible for the cross-linking in the gluten network. Using flour with higher gluten content leads to chewier doughs such as those found in
pizza Pizza is an Italian cuisine, Italian, specifically Neapolitan cuisine, Neapolitan, dish typically consisting of a flat base of Leavening agent, leavened wheat-based dough topped with tomato, cheese, and other ingredients, baked at a high t ...
and
bagel A bagel (; ; also spelled beigel) is a bread roll originating in the Jewish communities of Poland. Bagels are traditionally made from yeasted wheat dough that is shaped by hand into a torus or ring, briefly boiled in water, and then baked. ...
s, while using flour with less gluten content yields tender baked goods such as
pastry Pastry refers to a variety of Dough, doughs (often enriched with fat or eggs), as well as the sweet and savoury Baking, baked goods made from them. The dough may be accordingly called pastry dough for clarity. Sweetened pastries are often descr ...
products. Generally,
bread Bread is a baked food product made from water, flour, and often yeast. It is a staple food across the world, particularly in Europe and the Middle East. Throughout recorded history and around the world, it has been an important part of many cu ...
flours are high in gluten (hard wheat); pastry flours have a lower gluten content.
Kneading In cooking (and more specifically baking), kneading is a process in the making of bread or dough, used to mix the ingredients and add strength to the final product. It allows the process of baking to be shortened by developing the gluten more qu ...
promotes the formation of gluten strands and cross-links, creating baked products that are chewier (as opposed to more brittle or crumbly). The "chewiness" increases as the dough is kneaded for longer. An increased moisture content in the dough enhances gluten development, and very wet doughs left to rise for a long time require no kneading (see
no-knead bread No-knead bread is a method of bread baking that uses a very long fermentation (rising) time instead of kneading to form the gluten strands that give the bread its texture. It is characterized by a low yeast content and a very wet dough. The met ...
).
Shortening Shortening is any fat that is a solid at room temperature and is used to make crumbly pastry and other food products. The idea of shortening dates back to at least the 18th century, well before the invention of modern, shelf-stable vegetable ...
inhibits formation of cross-links and is used, along with diminished water and less kneading, when a tender and flaky product, such as a
pie crust Shortcrust is a type of pastry often used for the base of a tart, quiche, pie, or (in the British English sense) flan. Shortcrust pastry can be used to make both sweet and savory pies such as apple pie, quiche, lemon meringue or chicken pie. ...
, is desired. The strength and elasticity of gluten in flour is measured in the baking industry using a
farinograph In baking, a farinograph measures specific properties of flour. It was first developed and launched in 1928. The farinograph is a tool used for measuring the shear (fluid), shear and viscosity of a mixture of dough, flour and water. The primary un ...
. This gives the baker a measurement of quality for different varieties of flours when developing recipes for various baked goods.


Added gluten

In industrial production, a
slurry A slurry is a mixture of denser solids suspended in liquid, usually water. The most common use of slurry is as a means of transporting solids or separating minerals, the liquid being a carrier that is pumped on a device such as a centrifugal pu ...
of wheat flour is kneaded vigorously by machinery until the gluten agglomerates into a mass. This mass is collected by
centrifugation Centrifugation is a mechanical process which involves the use of the centrifugal force to separate particles from a solution according to their size, shape, density, medium viscosity and rotor speed. The denser components of the mixture migrate ...
, then transported through several stages integrated in a continuous process. About 65% of the water in the wet gluten is removed by means of a
screw press A screw press is a type of machine press in which the ram is driven up and down by a screw. The screw shaft can be driven by a handle or a wheel. It works by using a coarse screw to convert the rotation of the handle or drive-wheel into a small d ...
; the remainder is sprayed through an
atomizer nozzle Atomization refers to breaking bonds in some substance to obtain its constituent atoms in gas phase. By extension, it also means separating something into fine particles, for example: process of breaking bulk liquids into small droplets. Atomizati ...
into a
drying Drying is a mass transfer process consisting of the removal of water or another solvent by evaporation from a solid, semi-solid or liquid. This process is often used as a final production step before selling or packaging products. To be consider ...
chamber, where it remains at an elevated temperature for a short time to allow the water to evaporate without denaturing the gluten. The process yields a flour-like powder with a 7% moisture content, which is
air cooled Air-cooled engines rely on the circulation of air directly over heat dissipation fins or hot areas of the engine to cool them in order to keep the engine within operating temperatures. Air-cooled designs are far simpler than their liquid-cooled ...
and
pneumatically Pneumatics (from Greek 'wind, breath') is the use of gas or pressurized air in mechanical systems. Pneumatic systems used in industry are commonly powered by compressed air or compressed inert gases. A centrally located and electrically- ...
transported to a receiving vessel. In the final step, the processed gluten is sifted and milled to produce a uniform product. This flour-like powder, when added to ordinary
flour Flour is a powder made by Mill (grinding), grinding raw grains, List of root vegetables, roots, beans, Nut (fruit), nuts, or seeds. Flours are used to make many different foods. Cereal flour, particularly wheat flour, is the main ingredie ...
dough, may help improve the dough's ability to increase in volume. The resulting mixture also increases the bread's structural stability and chewiness. Gluten-added dough must be worked vigorously to induce it to rise to its full capacity; an automatic
bread machine A bread making machine or breadmaker or bread maker is a home appliance for baking bread. It consists of a bread pan (or "tin"), at the bottom of which are one or more built-in paddles, mounted in the center of a small special-purpose oven. The ...
or
food processor A food processor is a kitchen appliance used to facilitate repetitive tasks in the preparation of food. Today, the term almost always refers to an electric-motor-driven appliance, although there are some manual devices also referred to as "food ...
may be required for high-gluten kneading. Generally, higher gluten levels are associated with higher overall protein content.


Imitation meats

Gluten, especially
wheat gluten Gluten is a structural protein naturally found in certain cereal grains. The term ''gluten'' usually refers to the elastic network of a wheat grain's proteins, gliadin and glutenin primarily, that forms readily with the addition of water and oft ...
(seitan), is often the basis for imitation meats resembling
beef Beef is the culinary name for meat from cattle (''Bos taurus''). Beef can be prepared in various ways; Cut of beef, cuts are often used for steak, which can be cooked to varying degrees of doneness, while trimmings are often Ground beef, grou ...
,
chicken The chicken (''Gallus gallus domesticus'') is a domesticated subspecies of the red junglefowl (''Gallus gallus''), originally native to Southeast Asia. It was first domesticated around 8,000 years ago and is now one of the most common and w ...
,
duck Duck is the common name for numerous species of waterfowl in the family (biology), family Anatidae. Ducks are generally smaller and shorter-necked than swans and goose, geese, which are members of the same family. Divided among several subfam ...
(see mock duck),
fish A fish (: fish or fishes) is an aquatic animal, aquatic, Anamniotes, anamniotic, gill-bearing vertebrate animal with swimming fish fin, fins and craniate, a hard skull, but lacking limb (anatomy), limbs with digit (anatomy), digits. Fish can ...
and
pork Pork is the culinary name for the meat of the pig (''Sus domesticus''). It is the most commonly consumed meat worldwide, with evidence of pig animal husbandry, husbandry dating back to 8000–9000 BCE. Pork is eaten both freshly cooke ...
. When cooked in
broth Broth, also known as bouillon (), is a savory liquid made of water in which meat, fish, or vegetables have been simmered for a short period of time. It can be eaten alone, but it is most commonly used to prepare other dishes, such as soups ...
, gluten absorbs some of the surrounding liquid (including the flavor) and becomes firm to the bite. This use of gluten is a popular means of adding supplemental protein to many
vegetarian Vegetarianism is the practice of abstaining from the Eating, consumption of meat (red meat, poultry, seafood, insects as food, insects, and the flesh of any other animal). It may also include abstaining from eating all by-products of animal slau ...
diets. In home or restaurant cooking, wheat gluten is prepared from
flour Flour is a powder made by Mill (grinding), grinding raw grains, List of root vegetables, roots, beans, Nut (fruit), nuts, or seeds. Flours are used to make many different foods. Cereal flour, particularly wheat flour, is the main ingredie ...
by kneading the flour under water, agglomerating the gluten into an elastic network known as a
dough Dough is a malleable, sometimes elastic paste made from flour (which itself is made from grains or from leguminous or chestnut crops). Dough is typically made by mixing flour with a small amount of water or other liquid and sometimes includes ...
, and then washing out the
starch Starch or amylum is a polymeric carbohydrate consisting of numerous glucose units joined by glycosidic bonds. This polysaccharide is produced by most green plants for energy storage. Worldwide, it is the most common carbohydrate in human diet ...
.


Other consumer products

Gluten is often present in
beer Beer is an alcoholic beverage produced by the brewing and fermentation of starches from cereal grain—most commonly malted barley, although wheat, maize (corn), rice, and oats are also used. The grain is mashed to convert starch in the ...
and
soy sauce Soy sauce (sometimes called soya sauce in British English) is a liquid condiment of China, Chinese origin, traditionally made from a fermentation (food), fermented paste of soybeans, roasted cereal, grain, brine, and ''Aspergillus oryzae'' or ''A ...
, and can be used as a
stabilizing agent In industrial chemistry, a stabilizer or stabiliser is a chemical that is used to prevent degradation. Above all, heat and light stabilizers are added to plastic and rubber materials because they ensure safe processing and protect products against ...
in more unexpected food products, such as
ice cream Ice cream is a frozen dessert typically made from milk or cream that has been flavoured with a sweetener, either sugar or an alternative, and a spice, such as Chocolate, cocoa or vanilla, or with fruit, such as strawberries or peaches. Food ...
and
ketchup Ketchup or catsup is a table condiment with a sweet and sour flavor. "Ketchup" now typically refers to tomato ketchup, although early recipes for different varieties contained mushrooms, oysters, mussels, egg whites, grapes, or walnuts, amon ...
. Foods of this kind may therefore present problems for a small number of consumers because the hidden gluten constitutes a hazard for people with
celiac disease Coeliac disease (British English) or celiac disease (American English) is a long-term autoimmune disorder, primarily affecting the small intestine. Patients develop intolerance to gluten, which is present in foods such as wheat, rye, spel ...
and gluten sensitivities. The protein content of some
pet food Pet food is animal feed intended for consumption by pets. Typically sold in pet stores and supermarkets, it is usually specific to the type of animal, such as dog food or cat food. Most meat used for animals is a byproduct of the human food indus ...
s may also be enhanced by adding gluten. Gluten is also used in
cosmetics Cosmetics are substances that are intended for application to the body for cleansing, beautifying, promoting attractiveness, or altering appearance. They are mixtures of chemical compounds derived from either Natural product, natural source ...
, hair products and other
dermatological Dermatology is the branch of medicine dealing with the skin.''Random House Webster's Unabridged Dictionary.'' Random House, Inc. 2001. Page 537. . It is a speciality with both medical and surgical aspects. A dermatologist is a specialist medic ...
preparations.


Animal feed

Wheat gluten is used both as a protein source and binding ingredient in pet foods. Wheat gluten imported from China
adulterated An adulterant is a substance secretly added to another that may compromise the safety or effectiveness. Typical substances that are adulterated include food, cosmetics, pharmaceuticals or fuels. Definition Adulteration is the practice of secre ...
with
melamine Melamine is an organic compound with the formula C3H6N6. This white solid is a trimer (chemistry), trimer of cyanamide, with a 1,3,5-Triazine, 1,3,5-triazine skeleton. Like cyanamide, it contains 66% nitrogen by mass, and its derivatives ha ...
used in pet foods was considered to have caused harm in many countries in 2007.


Disorders

"Gluten-related disorders" is the umbrella term for all diseases triggered by gluten, which include
celiac disease Coeliac disease (British English) or celiac disease (American English) is a long-term autoimmune disorder, primarily affecting the small intestine. Patients develop intolerance to gluten, which is present in foods such as wheat, rye, spel ...
(CD),
non-celiac gluten sensitivity Non-celiac gluten sensitivity (NCGS) or gluten sensitivity is a controversial disorder which can cause both gastrointestinal and other problems. NCGS is included in the spectrum of gluten-related disorders. The definition and diagnostic criteria ...
(NCGS),
wheat allergy Wheat allergy is an allergy to wheat that typically presents as a food allergy, but can also be a contact allergy resulting from occupational exposure. The exact mechanism of this allergy is not yet clear. Wheat allergy may be immunoglobulin E-m ...
, gluten ataxia and
dermatitis herpetiformis Dermatitis herpetiformis (DH) is a chronic autoimmune blistering skin condition, characterised by intensely itchy blisters filled with a watery fluid. DH is a cutaneous manifestation of coeliac disease, although the exact causal mechanism is not ...
(DH).


Pathophysiological research

The gluten
peptide Peptides are short chains of amino acids linked by peptide bonds. A polypeptide is a longer, continuous, unbranched peptide chain. Polypeptides that have a molecular mass of 10,000 Da or more are called proteins. Chains of fewer than twenty am ...
s are responsible for triggering gluten-related disorders. In people who have celiac disease, the peptides trigger an immune response that causes injury of the intestines, ranging from
inflammation Inflammation (from ) is part of the biological response of body tissues to harmful stimuli, such as pathogens, damaged cells, or irritants. The five cardinal signs are heat, pain, redness, swelling, and loss of function (Latin ''calor'', '' ...
to partial or total destruction of the
intestinal villi Intestinal villi (: villus) are small, finger-like projections that extend into the lumen of the small intestine. Each villus is approximately 0.5–1.6 mm in length (in humans), and has many microvilli projecting from the enterocytes of i ...
. To study mechanisms of this damage, laboratory experiments are done ''in vitro'' and ''in vivo''. Among the gluten peptides,
gliadin Gliadin (a type of prolamin) is a class of proteins present in wheat and several other cereals within the grass genus ''Triticum''. Gliadins, which are a component of gluten, are essential for giving bread the ability to rise properly during ba ...
has been studied extensively.


''In vitro'' and ''in vivo'' studies

In the context of celiac disease, gliadin peptides are classified in
basic Basic or BASIC may refer to: Science and technology * BASIC, a computer programming language * Basic (chemistry), having the properties of a base * Basic access authentication, in HTTP Entertainment * Basic (film), ''Basic'' (film), a 2003 film ...
and
clinical research Clinical research is a branch of medical research that involves people and aims to determine the effectiveness (efficacy) and safety of medications, devices, diagnostic products, and treatment regimens intended for improving human health. The ...
as
immunogenic Immunogenicity is the ability of a foreign substance, such as an antigen, to provoke an immune response in the body of a human or other animal. It may be wanted or unwanted: * Wanted immunogenicity typically relates to vaccines, where the injectio ...
, depending on their
mechanism of action In pharmacology, the term mechanism of action (MOA) refers to the specific biochemical Drug interaction, interaction through which a Medication, drug substance produces its pharmacological effect. A mechanism of action usually includes mention o ...
: * The peptides are those capable of directly affecting cells and intestinal preparations ''in vitro'', producing cellular damage ''in vivo'' and eliciting the innate immune response. ''In vitro'', the peptides promote cell
apoptosis Apoptosis (from ) is a form of programmed cell death that occurs in multicellular organisms and in some eukaryotic, single-celled microorganisms such as yeast. Biochemistry, Biochemical events lead to characteristic cell changes (Morphology (biol ...
(a form of
programmed cell death Programmed cell death (PCD) sometimes referred to as cell, or cellular suicide is the death of a cell (biology), cell as a result of events inside of a cell, such as apoptosis or autophagy. PCD is carried out in a biological process, which usual ...
) and inhibit the synthesis of
nucleic acid Nucleic acids are large biomolecules that are crucial in all cells and viruses. They are composed of nucleotides, which are the monomer components: a pentose, 5-carbon sugar, a phosphate group and a nitrogenous base. The two main classes of nuclei ...
s (DNA and RNA) and proteins, reducing the viability of cells. Experiments ''in vivo'' with normal mice showed that they cause an increase in cell death and the production of
interferon type I The type-I interferons (IFN) are cytokines which play essential roles in inflammation, immunoregulation, tumor cells recognition, and T-cell responses. In the human genome, a cluster of thirteen functional IFN genes is located at the 9p21.3 cy ...
(an inflammatory mediator). ''In vitro'', gluten alters cellular
morphology Morphology, from the Greek and meaning "study of shape", may refer to: Disciplines *Morphology (archaeology), study of the shapes or forms of artifacts *Morphology (astronomy), study of the shape of astronomical objects such as nebulae, galaxies, ...
and
motility Motility is the ability of an organism to move independently using metabolism, metabolic energy. This biological concept encompasses movement at various levels, from whole organisms to cells and subcellular components. Motility is observed in ...
,
cytoskeleton The cytoskeleton is a complex, dynamic network of interlinking protein filaments present in the cytoplasm of all cells, including those of bacteria and archaea. In eukaryotes, it extends from the cell nucleus to the cell membrane and is compos ...
organization, oxidative balance, and
tight junction Tight junctions, also known as occluding junctions or ''zonulae occludentes'' (singular, ''zonula occludens''), are multiprotein Cell junction, junctional complexes between epithelial cells, sealing and preventing leakage of solutes and water. Th ...
s. * The immunogenic peptides are those able to activate
T cell T cells (also known as T lymphocytes) are an important part of the immune system and play a central role in the adaptive immune response. T cells can be distinguished from other lymphocytes by the presence of a T-cell receptor (TCR) on their cell ...
s ''in vitro''. At least 50
epitope An epitope, also known as antigenic determinant, is the part of an antigen that is recognized by the immune system, specifically by antibodies, B cells, or T cells. The part of an antibody that binds to the epitope is called a paratope. Although e ...
s of gluten may produce cytotoxic, immunomodulatory, and gut-permeating activities. The effect of oat peptides (avenins) in celiac people depends on the oat
cultivar A cultivar is a kind of Horticulture, cultivated plant that people have selected for desired phenotypic trait, traits and which retains those traits when Plant propagation, propagated. Methods used to propagate cultivars include division, root a ...
consumed because of prolamin genes, protein amino acid sequences, and the immunotoxicity of prolamins which vary among oat varieties. In addition, oat products may be cross-contaminated with the other gluten-containing
cereal A cereal is a grass cultivated for its edible grain. Cereals are the world's largest crops, and are therefore staple foods. They include rice, wheat, rye, oats, barley, millet, and maize ( Corn). Edible grains from other plant families, ...
s.


Incidence

, gluten-related disorders were increasing in frequency in different geographic areas. Some suggested explanations for this increase include the following: the growing westernization of diets, the increasing use of wheat-based foods included in the
Mediterranean diet The Mediterranean diet is a concept first proposed in 1975 by the American biologist Ancel Keys and chemist Margaret Keys. The diet took inspiration from the eating habits and traditional food typical of Crete, much of the rest of Greece, and s ...
, the progressive replacement of rice by wheat in many countries in Asia, the Middle East, and North Africa, the higher content of gluten in bread and bakery products due to the reduction of dough fermentation time, and the development in recent years of new types of wheat with a higher amount of
cytotoxic Cytotoxicity is the quality of being toxic to cells. Examples of toxic agents are toxic metals, toxic chemicals, microbe neurotoxins, radiation particles and even specific neurotransmitters when the system is out of balance. Also some types of dr ...
gluten
peptide Peptides are short chains of amino acids linked by peptide bonds. A polypeptide is a longer, continuous, unbranched peptide chain. Polypeptides that have a molecular mass of 10,000 Da or more are called proteins. Chains of fewer than twenty am ...
s, However, a 2020 study that grew and analyzed 60 wheat cultivars from between 1891 and 2010 found no changes in albumin/globulin and gluten contents over time. "Overall, the harvest year had a more significant effect on protein composition than the cultivar. At the protein level, we found no evidence to support an increased
immunostimulatory Immunostimulants, also known as immunostimulators, are substances (drugs and nutrients) that stimulate the immune system usually in a non-specific manner by inducing activation or increasing activity of any of its components. One notable example i ...
potential of modern winter wheat."


Celiac disease

Celiac disease Coeliac disease (British English) or celiac disease (American English) is a long-term autoimmune disorder, primarily affecting the small intestine. Patients develop intolerance to gluten, which is present in foods such as wheat, rye, spel ...
(CD) is a chronic, multiple-organ
autoimmune disorder An autoimmune disease is a condition that results from an anomalous response of the adaptive immune system, wherein it mistakenly targets and attacks healthy, functioning parts of the body as if they were foreign organisms. It is estimated tha ...
primarily affecting the
small intestine The small intestine or small bowel is an organ (anatomy), organ in the human gastrointestinal tract, gastrointestinal tract where most of the #Absorption, absorption of nutrients from food takes place. It lies between the stomach and large intes ...
caused by the ingestion of wheat, barley, rye, oats, and derivatives, that appears in genetically predisposed people of all ages. CD is not only a gastrointestinal disease, because it may involve several organs and cause an extensive variety of non-gastrointestinal symptoms, and most importantly, it may be apparently asymptomatic. Many asymptomatic people become accustomed to living with a chronic bad health status as if it were normal, but they are able to recognize that they actually had symptoms related to celiac disease after starting a gluten-free diet and improvement occurs. Added difficulties for diagnosis are the fact that serological markers ( anti-tissue transglutaminase G2 are not always present and many people may have minor mucosal lesions, without atrophy of the
intestinal villi Intestinal villi (: villus) are small, finger-like projections that extend into the lumen of the small intestine. Each villus is approximately 0.5–1.6 mm in length (in humans), and has many microvilli projecting from the enterocytes of i ...
. CD affects approximately 1–2% of the general population, but most cases remain unrecognized, undiagnosed and untreated, and at risk for serious long-term health complications. People may suffer severe disease symptoms and be subjected to extensive investigations for many years, before a proper diagnosis is achieved. Untreated CD may cause
malabsorption Malabsorption is a state arising from abnormality in absorption of food nutrients across the gastrointestinal (GI) tract. Impairment can be of single or multiple nutrients depending on the abnormality. This may lead to malnutrition and a varie ...
, reduced quality of life,
iron deficiency Iron deficiency, or sideropenia, is the state in which a body lacks enough iron to supply its needs. Iron is present in all cells in the human body and has several vital functions, such as carrying oxygen to the tissues from the lungs as a key ...
,
osteoporosis Osteoporosis is a systemic skeletal disorder characterized by low bone mass, micro-architectural deterioration of bone tissue leading to more porous bone, and consequent increase in Bone fracture, fracture risk. It is the most common reason f ...
, an increased risk of intestinal
lymphoma Lymphoma is a group of blood and lymph tumors that develop from lymphocytes (a type of white blood cell). The name typically refers to just the cancerous versions rather than all such tumours. Signs and symptoms may include enlarged lymph node ...
s, and greater mortality. CD is associated with some other autoimmune diseases, such as
diabetes mellitus type 1 Type 1 diabetes (T1D), formerly known as juvenile diabetes, is an autoimmune disease that occurs when the body's immune system destroys pancreatic cells (beta cells). In healthy persons, beta cells produce insulin. Insulin is a hormone required ...
,
thyroiditis Thyroiditis is the inflammation of the thyroid gland. The thyroid gland is located on the front of the neck below the laryngeal prominence, and makes hormones that control metabolism. Thyroiditis is a group of disorders that all cause thyroi ...
, gluten ataxia,
psoriasis Psoriasis is a long-lasting, noncontagious autoimmune disease characterized by patches of abnormal skin. These areas are red, pink, or purple, dry, itchy, and scaly. Psoriasis varies in severity from small localized patches to complete b ...
,
vitiligo Vitiligo (, ) is a chronic autoimmune disorder that causes patches of skin to lose pigment or color. The cause of vitiligo is unknown, but it may be related to immune system changes, genetic factors, stress, or sun exposure, and susceptibili ...
,
autoimmune hepatitis Autoimmune hepatitis, formerly known as lupoid hepatitis, plasma cell hepatitis, or autoimmune chronic active hepatitis, is a chronic, autoimmune disease of the liver that occurs when the body's immune system attacks liver cells, causing the liv ...
,
dermatitis herpetiformis Dermatitis herpetiformis (DH) is a chronic autoimmune blistering skin condition, characterised by intensely itchy blisters filled with a watery fluid. DH is a cutaneous manifestation of coeliac disease, although the exact causal mechanism is not ...
,
primary sclerosing cholangitis Primary sclerosing cholangitis (PSC) is a long-term progressive disease of the liver and gallbladder characterized by inflammation and scarring of the bile ducts, which normally allow bile to drain from the gallbladder. Affected individuals may ...
, and more. CD with "classic symptoms", which include gastrointestinal manifestations such as chronic diarrhea and abdominal distention, malabsorption, loss of appetite, and impaired growth, is currently the least common presentation form of the disease and affects predominantly small children generally younger than two years of age. CD with "non-classic symptoms" is the most common clinical type and occurs in older children (over two years old), adolescents, and adults. It is characterized by milder or even absent gastrointestinal symptoms and a wide spectrum of non-intestinal manifestations that can involve any organ of the body, and very frequently may be completely asymptomatic both in children (at least in 43% of the cases) and adults. Asymptomatic CD (ACD) is present in the majority of affected patients and is characterized by the absence of classical gluten-intolerance signs, such as diarrhea, bloating, and abdominal pain. Nevertheless, these individuals very often develop diseases that can be related with gluten intake. Gluten can be degraded into several morphine-like substances, named
gluten exorphin Gluten exorphins are a group of opioid peptides formed during the digestion of the gluten protein. These peptides work as external regulators for gastrointestinal movement and hormonal release. The breakdown of gliadin, a polymer of wheat proteins, ...
s. These compounds have proven opioid effects and could mask the deleterious effects of gluten protein on gastrointestinal lining and function.


Non-celiac gluten sensitivity

Non-celiac gluten sensitivity (NCGS) is described as a condition of multiple symptoms that improves when switching to a
gluten-free diet A gluten-free diet (GFD) is a nutritional plan that strictly excludes gluten, which is a mixture of prolamin proteins found in wheat (and all of its species and hybrids, such as spelt, kamut, and triticale), as well as barley, rye, and oats ...
, after celiac disease and wheat allergy are excluded. Recognized since 2010, it is included among
gluten-related disorders Gluten-related disorders is the term for the diseases triggered by gluten, including celiac disease (CD), non-celiac gluten sensitivity (NCGS), gluten ataxia, dermatitis herpetiformis (DH) and wheat allergy. The umbrella category has also been r ...
. Its
pathogenesis In pathology, pathogenesis is the process by which a disease or disorder develops. It can include factors which contribute not only to the onset of the disease or disorder, but also to its progression and maintenance. The word comes . Descript ...
is not yet well understood, but the activation of the innate immune system, the direct negative effects of gluten and probably other wheat components, are implicated. NCGS is the most common syndrome of
gluten intolerance Gluten-related disorders is the term for the diseases triggered by gluten, including celiac disease (CD), non-celiac gluten sensitivity (NCGS), gluten ataxia, dermatitis herpetiformis (DH) and wheat allergy. The umbrella category has also been ...
, with a prevalence estimated to be 6-10%. NCGS is becoming a more common diagnosis, but its true prevalence is difficult to determine because many people self-diagnose and start a gluten-free diet, without having previously tested for celiac disease or having the dietary prescription from a physician. People with NCGS and gastrointestinal symptoms remain habitually in a "no man's land", without being recognized by the specialists and lacking the adequate medical care and treatment. Most of these people have a long history of health complaints and unsuccessful consultations with numerous physicians, trying to get a diagnosis of celiac disease, but they are only labeled as
irritable bowel syndrome Irritable bowel syndrome (IBS) is a functional gastrointestinal disorder characterized by a group of symptoms that commonly include abdominal pain, abdominal bloating, and changes in the consistency of bowel movements. These symptoms may ...
. A consistent although undefined number of people eliminate gluten because they identify it as responsible for their symptoms and these improve with the
gluten-free diet A gluten-free diet (GFD) is a nutritional plan that strictly excludes gluten, which is a mixture of prolamin proteins found in wheat (and all of its species and hybrids, such as spelt, kamut, and triticale), as well as barley, rye, and oats ...
, so they self-diagnose as NCGS. People with NCGS may develop gastrointestinal symptoms, which resemble those of
irritable bowel syndrome Irritable bowel syndrome (IBS) is a functional gastrointestinal disorder characterized by a group of symptoms that commonly include abdominal pain, abdominal bloating, and changes in the consistency of bowel movements. These symptoms may ...
or
wheat allergy Wheat allergy is an allergy to wheat that typically presents as a food allergy, but can also be a contact allergy resulting from occupational exposure. The exact mechanism of this allergy is not yet clear. Wheat allergy may be immunoglobulin E-m ...
, or a wide variety of non-gastrointestinal symptoms, such as
headache A headache, also known as cephalalgia, is the symptom of pain in the face, head, or neck. It can occur as a migraine, tension-type headache, or cluster headache. There is an increased risk of Depression (mood), depression in those with severe ...
, chronic
fatigue Fatigue is a state of tiredness (which is not sleepiness), exhaustion or loss of energy. It is a signs and symptoms, symptom of any of various diseases; it is not a disease in itself. Fatigue (in the medical sense) is sometimes associated wit ...
,
fibromyalgia Fibromyalgia (FM) is a functional somatic syndrome with symptoms of widespread chronic pain, accompanied by fatigue, sleep disturbance including awakening unrefreshed, and Cognitive deficit, cognitive symptoms. Other symptoms can include he ...
, atopic diseases,
allergies Allergies, also known as allergic diseases, are various conditions caused by hypersensitivity of the immune system to typically harmless substances in the environment. These diseases include Allergic rhinitis, hay fever, Food allergy, food al ...
,
neurological diseases Neurological disorders represent a complex array of medical conditions that fundamentally disrupt the functioning of the nervous system. These disorders affect the brain, spinal cord, and nerve networks, presenting unique diagnosis, treatment, and ...
, or
psychiatric disorders A mental disorder, also referred to as a mental illness, a mental health condition, or a psychiatric disability, is a behavioral or mental pattern that causes significant distress or impairment of personal functioning. A mental disorder is ...
, among others. The results of a 2017 study suggest that NCGS may be a chronic disorder, as is the case with celiac disease. Besides gluten, additional components present in wheat, rye, barley, oats, and their derivatives, including other proteins called amylase-trypsin inhibitors (ATIs) and short-chain
carbohydrates A carbohydrate () is a biomolecule composed of carbon (C), hydrogen (H), and oxygen (O) atoms. The typical hydrogen-to-oxygen atomic ratio is 2:1, analogous to that of water, and is represented by the empirical formula (where ''m'' and ''n'' ma ...
known as
FODMAP FODMAPs (''fermentable oligosaccharides, disaccharides, monosaccharides, and polyols'') are short-chain carbohydrates that are poorly absorbed in the small intestine and ferment in the colon. They include short-chain oligosaccharide polymers of fr ...
s, may cause NCGS symptoms. As of 2019, reviews conclude that although FODMAPs present in wheat and related grains may play a role in non-celiac gluten sensitivity, they only explain certain gastrointestinal symptoms, such as
bloating Abdominal bloating (or simply bloating) is a short-term disease that affects the gastrointestinal tract. Bloating is generally characterized by an excess buildup of gas, air or fluids in the stomach. A person may have feelings of tightness, pressu ...
, but not the extra-digestive symptoms that people with non-celiac gluten sensitivity may develop, such as
neurological disorder Neurological disorders represent a complex array of medical conditions that fundamentally disrupt the functioning of the nervous system. These disorders affect the brain, spinal cord, and nerve networks, presenting unique diagnosis, treatment, and ...
s,
fibromyalgia Fibromyalgia (FM) is a functional somatic syndrome with symptoms of widespread chronic pain, accompanied by fatigue, sleep disturbance including awakening unrefreshed, and Cognitive deficit, cognitive symptoms. Other symptoms can include he ...
, psychological disturbances, and
dermatitis Dermatitis is a term used for different types of skin inflammation, typically characterized by itchiness, redness and a rash. In cases of short duration, there may be small blisters, while in long-term cases the skin may become thickened ...
. ATIs may cause toll-like receptor 4 (
TLR4 Toll-like receptor 4 (TLR4), also designated as CD284 (cluster of differentiation 284), is a key activator of the innate immune response and plays a central role in the fight against bacterial infections. TLR4 is a transmembrane protein of approx ...
)-mediated intestinal
inflammation Inflammation (from ) is part of the biological response of body tissues to harmful stimuli, such as pathogens, damaged cells, or irritants. The five cardinal signs are heat, pain, redness, swelling, and loss of function (Latin ''calor'', '' ...
in humans.


Wheat allergy

People can also experience adverse effects of wheat as result of a
wheat allergy Wheat allergy is an allergy to wheat that typically presents as a food allergy, but can also be a contact allergy resulting from occupational exposure. The exact mechanism of this allergy is not yet clear. Wheat allergy may be immunoglobulin E-m ...
. As with most allergies, a wheat allergy causes the immune system to respond abnormally to a component of wheat that it treats as a threatening foreign body. This immune response is often time-limited and does not cause lasting harm to body tissues. Wheat allergy and celiac disease are different disorders. Gastrointestinal symptoms of wheat allergy are similar to those of celiac disease and non-celiac gluten sensitivity, but there is a different interval between exposure to wheat and onset of symptoms. An allergic reaction to wheat has a fast onset (from minutes to hours) after the consumption of food containing wheat and could include
anaphylaxis Anaphylaxis (Greek: 'up' + 'guarding') is a serious, potentially fatal allergic reaction and medical emergency that is rapid in onset and requires immediate medical attention regardless of the use of emergency medication on site. It typicall ...
.


Gluten ataxia

Gluten ataxia is an autoimmune disease triggered by the ingestion of gluten. With gluten ataxia, damage takes place in the
cerebellum The cerebellum (: cerebella or cerebellums; Latin for 'little brain') is a major feature of the hindbrain of all vertebrates. Although usually smaller than the cerebrum, in some animals such as the mormyrid fishes it may be as large as it or eve ...
, the balance center of the brain that controls coordination and complex movements like walking, speaking and swallowing, with loss of
Purkinje cell Purkinje cells or Purkinje neurons, named for Czech physiologist Jan Evangelista Purkyně who identified them in 1837, are a unique type of prominent, large neuron located in the Cerebellum, cerebellar Cortex (anatomy), cortex of the brain. Wi ...
s. People with gluten ataxia usually present
gait abnormality Gait abnormality is a deviation from normal walking (gait). Watching a patient walk is an important part of the neurological examination. Normal gait requires that many systems, including strength, sensation and coordination, function in an integ ...
or incoordination and tremor of the upper limbs. Gaze-evoked
nystagmus Nystagmus is a condition of involuntary (or voluntary, in some cases) Eye movement (sensory), eye movement. People can be born with it but more commonly acquire it in infancy or later in life. In many cases it may result in visual impairment, re ...
and other ocular signs of cerebellar dysfunction are common.
Myoclonus Myoclonus is a brief, involuntary, irregular (lacking rhythm) twitching of a muscle, a joint, or a group of muscles, different from clonus, which is rhythmic or regular. Myoclonus ( myo- "muscle", clonus "spasm") describes a medical sign and, ...
, palatal tremor, and opsoclonus-myoclonus may also appear. Early diagnosis and treatment with a
gluten-free diet A gluten-free diet (GFD) is a nutritional plan that strictly excludes gluten, which is a mixture of prolamin proteins found in wheat (and all of its species and hybrids, such as spelt, kamut, and triticale), as well as barley, rye, and oats ...
can improve ataxia and prevent its progression. The effectiveness of the treatment depends on the elapsed time from the onset of the ataxia until diagnosis, because the death of neurons in the cerebellum as a result of gluten exposure is irreversible. Gluten ataxia accounts for 40% of ataxias of unknown origin and 15% of all ataxias. Less than 10% of people with gluten ataxia present any gastrointestinal symptom, yet about 40% have intestinal damage.


Other neurological disorders

In addition to gluten ataxia, gluten sensitivity can cause a wide spectrum of neurological disorders, which develop with or without the presence of digestive symptoms or intestinal damage. These include
peripheral neuropathy Peripheral neuropathy, often shortened to neuropathy, refers to damage or disease affecting the nerves. Damage to nerves may impair sensation, movement, gland function, and/or organ function depending on which nerve fibers are affected. Neuropa ...
,
epilepsy Epilepsy is a group of Non-communicable disease, non-communicable Neurological disorder, neurological disorders characterized by a tendency for recurrent, unprovoked Seizure, seizures. A seizure is a sudden burst of abnormal electrical activit ...
,
headache A headache, also known as cephalalgia, is the symptom of pain in the face, head, or neck. It can occur as a migraine, tension-type headache, or cluster headache. There is an increased risk of Depression (mood), depression in those with severe ...
,
encephalopathy Encephalopathy (; ) means any disorder or disease of the brain, especially chronic degenerative conditions. In modern usage, encephalopathy does not refer to a single disease, but rather to a syndrome of overall brain dysfunction; this syndrome ...
, vascular
dementia Dementia is a syndrome associated with many neurodegenerative diseases, characterized by a general decline in cognitive abilities that affects a person's ability to perform activities of daily living, everyday activities. This typically invo ...
, and various
movement disorder Movement disorders are clinical syndromes with either an excess of movement or a paucity of voluntary and involuntary movements, unrelated to weakness or spasticity. Movement disorders present with extrapyramidal symptoms and are caused by basa ...
s (
restless legs syndrome Restless legs syndrome (RLS), also known as Willis–Ekbom disease (WED), is a neurological disorder, usually chronic, that causes an overwhelming urge to move one's legs. There is often an unpleasant feeling in the legs that improves temporaril ...
,
chorea Chorea, or (rarely) choreia, () is an abnormal involuntary movement disorder, characterized by quick movements of the hands or feet. It is one of a group of neurological disorders called dyskinesias. The term ''chorea'' is derived , as the move ...
,
parkinsonism Parkinsonism is a clinical syndrome characterized by tremor, bradykinesia (slowed movements), Rigidity (neurology), rigidity, and balance disorder, postural instability. Both hypokinetic features (bradykinesia and akinesia) and hyperkinetic f ...
,
Tourette syndrome Tourette syndrome (TS), or simply Tourette's, is a common neurodevelopmental disorder that begins in childhood or adolescence. It is characterized by multiple movement (motor) tics and at least one vocal (phonic) tic. Common tics are blinkin ...
, palatal tremor,
myoclonus Myoclonus is a brief, involuntary, irregular (lacking rhythm) twitching of a muscle, a joint, or a group of muscles, different from clonus, which is rhythmic or regular. Myoclonus ( myo- "muscle", clonus "spasm") describes a medical sign and, ...
,
dystonia Dystonia is a neurology, neurological Hyperkinesia, hyperkinetic Movement disorders, movement disorder in which sustained or repetitive muscle contractions occur involuntarily, resulting in twisting and repetitive movements or abnormal fixed po ...
,
opsoclonus myoclonus syndrome Opsoclonus myoclonus syndrome (OMS), also known as opsoclonus-myoclonus-ataxia (OMA), is a rare neurological disease, disorder of unknown cause which appears to be the result of an autoimmune process involving the nervous system. It is an extremel ...
,
paroxysms Paroxysmal attacks or paroxysms are a sudden recurrence or intensification of symptoms, such as a spasm or seizure. These short, frequent symptoms can be observed in various clinical conditions. They are usually associated with multiple scleros ...
,
dyskinesia Dyskinesia refers to a category of movement disorders that are characterized by involuntary muscle movements, including movements similar to tics or chorea and diminished voluntary movements. Dyskinesia can be anything from a slight tremor of t ...
, myorhythmia,
myokymia Myokymia is an involuntary, spontaneous, localized quivering of a few muscles, or bundles within a muscle, but which are insufficient to move a joint. One type is superior oblique myokymia. Myokymia is commonly used to describe an involuntary ey ...
). The diagnosis of underlying gluten sensitivity is complicated and delayed when there are no digestive symptoms. People who do experience gastrointestinal problems are more likely to receive a correct diagnosis and treatment. A strict gluten-free diet is the first-line treatment, which should be started as soon as possible. It is effective in most of these disorders. When dementia has progressed to an advanced degree, the diet has no beneficial effect. Cortical myoclonus appears to be treatment-resistant on both gluten-free diet and immunosuppression.


Labeling

People with gluten-related disorders have to remove gluten from their diet strictly, so they need clear labeling rules. The term "gluten-free" is generally used to indicate a supposed harmless level of gluten rather than a complete absence. The exact level at which gluten is harmless is uncertain and controversial. A 2008
systematic review A systematic review is a scholarly synthesis of the evidence on a clearly presented topic using critical methods to identify, define and assess research on the topic. A systematic review extracts and interprets data from published studies on ...
tentatively concluded that consumption of less than 10 mg of gluten per day is unlikely to cause intestinal damage in people with celiac disease, although it noted that few reliable studies had been done. Regulation of the label "gluten-free" varies.


International standards

The ''
Codex Alimentarius The is a collection of internationally recognized standards, codes of practice, guidelines, and other recommendations published by the Food and Agriculture Organization (FAO) and World Health Organization (WHO) of the United Nations relating to f ...
''
international standard An international standard is a technical standard developed by one or more international standards organizations. International standards are available for consideration and use worldwide. The most prominent such organization is the International O ...
s for
food labeling The packaging and labeling of food is subject to regulation in most regions/jurisdictions, both to prevent false advertising and to promote food safety. Regulations by type Multi-faceted * Codex Alimentarius (international voluntary standard ...
has a standard relating to the labeling of products as "
gluten-free A gluten-free diet (GFD) is a nutritional plan that strictly excludes gluten, which is a mixture of prolamin proteins found in wheat (and all of its species and hybrids, such as spelt, kamut, and triticale), as well as barley, rye, and oats. ...
". It only applies to foods that would normally contain gluten.


Brazil

By law in Brazil, all food products must display labels clearly indicating whether or not they contain gluten.


Canada

Labels for all food products sold in Canada must clearly identify the presence of gluten if it is present at a level greater than 20 parts per million.


European Union and United Kingdom

In the European Union, all prepackaged foods and non-prepacked foods from a restaurant, take-out food wrapped just before sale, or unpackaged food served in institutions must be identified if gluten-free. "Gluten-free" is defined as 20 parts per million of gluten or less and "very low gluten" is 100 parts per million of gluten or less; only foods with cereal ingredients processed to remove gluten can claim "very low gluten" on labels. It is not allowed to label food as "gluten-free" when all similar food is naturally gluten-free, such as in the case of milk. All foods containing gluten as an ingredient must be labelled accordingly as gluten is defined as one of the 14 recognised EU allergens.


United States

In the United States, gluten is not listed on labels unless added as a standalone ingredient. Wheat or other allergens are listed after the ingredient line. The
US Food and Drug Administration The United States Food and Drug Administration (FDA or US FDA) is a federal agency of the Department of Health and Human Services. The FDA is responsible for protecting and promoting public health through the control and supervision of food ...
(FDA) has historically classified gluten as "
generally recognized as safe Generally recognized as safe (GRAS) is a United States Food and Drug Administration (FDA) designation that a chemical or substance added to food is considered safe by experts under the conditions of its intended use. An ingredient with a GRAS d ...
" (GRAS). In August 2013, the FDA issued a final ruling, effective August 2014, that defined the term "gluten-free" for voluntary use in the labeling of foods as meaning that the amount of gluten contained in the food is below 20 parts per million.


See also

* * *


References


Further reading

* * {{Authority control Nutrition Seed storage proteins