Gluten-free diet

File:Amount of gluten that can causes a reaction.png of this size contains enough gluten to reactivate the autoimmune response in people with coeliac disease when they are following a gluten-free diet, although obvious symptoms may not appear.{{cite journal | vauthors = Moreno ML, Rodríguez-Herrera A, Sousa C, Comino I | title = Biomarkers to Monitor Gluten-Free Diet Compliance in Celiac Patients | journal = Nutrients | volume = 9 | issue = 1 | pages = 46 | date = January 2017 | pmid = 28067823 | pmc = 5295090 | doi = 10.3390/nu9010046 | type = Review | doi-access = free }} Consuming gluten even in small quantities, which may be the result of inadvertent cross-contamination, impedes recovery in people with gluten-related disorders.{{cite journal | vauthors = Mulder CJ, van Wanrooij RL, Bakker SF, Wierdsma N, Bouma G | title = Gluten-free diet in gluten-related disorders | journal = Digestive Diseases | volume = 31 | issue = 1 | pages = 57–62 | date = 2013 | pmid = 23797124 | doi = 10.1159/000347180 | type = Review | s2cid = 14124370 }}{{cite journal | vauthors = Hadjivassiliou M, Grünewald RA, Davies-Jones GA | title = Gluten sensitivity as a neurological illness | journal = Journal of Neurology, Neurosurgery, and Psychiatry | volume = 72 | issue = 5 | pages = 560–3 | date = May 2002 | pmid = 11971034 | pmc = 1737870 | doi = 10.1136/jnnp.72.5.560 | type = Review | quote = Incomplete elimination of gluten from the diet may be enough to abolish gastrointestinal symptoms with recovery of the small bowel mucosa but is insufficient to arrest the state of heightened immunological responsiveness resulting in neuronal injury. There is a group of patients with CD 'resistant' to gluten-free diet. This may reflect hypersensitivity to the minute amounts of gluten present in most 'gluten-free' products. }}{{cite journal | vauthors = Francavilla R, Cristofori F, Stella M, Borrelli G, Naspi G, Castellaneta S | title = Treatment of celiac disease: from gluten-free diet to novel therapies | journal = Minerva Pediatrica | volume = 66 | issue = 5 | pages = 501–16 | date = October 2014 | pmid = 24938882 | type = Review }}{{cite journal | vauthors = Antiga E, Caproni M | title = The diagnosis and treatment of dermatitis herpetiformis | journal = Clinical, Cosmetic and Investigational Dermatology | volume = 8 | pages = 257–65 | year = 2015 | pmid = 25999753 | pmc = 4435051 | doi = 10.2147/CCID.S69127 | type = Review | doi-access = free }}]]

{{Main|Coeliac disease}}

Coeliac disease (American English: celiac) (CD) is a chronic, immune-mediated, and mainly intestinal process, that appears in genetically predisposed people of all ages. It is caused by the ingestion of gluten, which is present in wheat, barley, rye and derivatives. Coeliac disease is not only a gastrointestinal disease, because it may affect several organs and cause an extensive variety of non-gastrointestinal symptoms, and most importantly, it may often be completely asymptomatic. Added difficulties for diagnosis are the fact that serological markers (anti-tissue transglutaminase [TG2]) are not always present,{{cite journal | vauthors = Fasano A, Catassi C | title = Clinical practice. Celiac disease | journal = The New England Journal of Medicine | volume = 367 | issue = 25 | pages = 2419–26 | date = December 2012 | pmid = 23252527 | doi = 10.1056/NEJMcp1113994 }} and many people with coeliac may have minor mucosal lesions, without atrophy of the intestinal villi.{{cite journal | vauthors = Bold J, Rostami K | title = Gluten tolerance; potential challenges in treatment strategies | journal = Gastroenterology and Hepatology from Bed to Bench | volume = 4 | issue = 2 | pages = 53–7 | date = 2011 | pmid = 24834157 | pmc = 4017406 }}

Coeliac disease affects approximately 1–2% of the general population all over the world{{cite journal | vauthors = Lundin KE, Wijmenga C | title = Coeliac disease and autoimmune disease-genetic overlap and screening | journal = Nature Reviews. Gastroenterology & Hepatology | volume = 12 | issue = 9 | pages = 507–15 | date = September 2015 | pmid = 26303674 | doi = 10.1038/nrgastro.2015.136 | s2cid = 24533103 }} and is on the increase,{{cite journal | vauthors = Lionetti E, Gatti S, Pulvirenti A, Catassi C | title = Celiac disease from a global perspective | journal = Best Practice & Research. Clinical Gastroenterology | volume = 29 | issue = 3 | pages = 365–79 | date = June 2015 | pmid = 26060103 | doi = 10.1016/j.bpg.2015.05.004 | type = Review }} but most cases remain unrecognized, undiagnosed and untreated, exposing patients to the risk of long-term complications.{{cite journal | vauthors = Fasano A | title = Clinical presentation of celiac disease in the pediatric population | journal = Gastroenterology | volume = 128 | issue = 4 Suppl 1 | pages = S68-73 | date = April 2005 | pmid = 15825129 | doi = 10.1053/j.gastro.2005.02.015 }}{{cite journal | vauthors = Elli L, Branchi F, Tomba C, Villalta D, Norsa L, Ferretti F, Roncoroni L, Bardella MT | display-authors = 6 | title = Diagnosis of gluten related disorders: Celiac disease, wheat allergy and non-celiac gluten sensitivity | journal = World Journal of Gastroenterology | volume = 21 | issue = 23 | pages = 7110–9 | date = June 2015 | pmid = 26109797 | pmc = 4476872 | doi = 10.3748/wjg.v21.i23.7110 | doi-access = free }} People may develop severe disease symptoms and be subjected to extensive investigations for many years before a proper diagnosis is achieved.{{cite journal | vauthors = Ludvigsson JF, Card T, Ciclitira PJ, Swift GL, Nasr I, Sanders DS, Ciacci C | title = Support for patients with celiac disease: A literature review | journal = United European Gastroenterology Journal | volume = 3 | issue = 2 | pages = 146–59 | date = April 2015 | pmid = 25922674 | pmc = 4406900 | doi = 10.1177/2050640614562599 | type = Review }} Untreated coeliac disease may cause malabsorption, reduced quality of life, iron deficiency, osteoporosis, obstetric complications (stillbirth, intrauterine growth restriction, preterm birth, low birthweight, and small for gestational age),{{cite journal | vauthors = Saccone G, Berghella V, Sarno L, Maruotti GM, Cetin I, Greco L, Khashan AS, McCarthy F, Martinelli D, Fortunato F, Martinelli P | display-authors = 6 | title = Celiac disease and obstetric complications: a systematic review and metaanalysis | journal = American Journal of Obstetrics and Gynecology | volume = 214 | issue = 2 | pages = 225–234 | date = February 2016 | pmid = 26432464 | doi = 10.1016/j.ajog.2015.09.080 | hdl = 11369/330101 | hdl-access = free }} an increased risk of intestinal lymphomas and greater mortality. Coeliac disease is associated with some autoimmune diseases, such as diabetes mellitus type 1, thyroiditis, gluten ataxia, psoriasis, vitiligo, autoimmune hepatitis, dermatitis herpetiformis, primary sclerosing cholangitis, and more.

Coeliac disease 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 of the disease and affects predominantly small children generally younger than two years of age.

Coeliac disease 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{{cite journal | vauthors = Vriezinga SL, Schweizer JJ, Koning F, Mearin ML | title = Coeliac disease and gluten-related disorders in childhood | journal = Nature Reviews. Gastroenterology & Hepatology | volume = 12 | issue = 9 | pages = 527–36 | date = September 2015 | pmid = 26100369 | doi = 10.1038/nrgastro.2015.98 | type = Review | s2cid = 2023530 }}) and adults.

Following a lifelong gluten-free diet is the only medically accepted treatment for people with coeliac disease.{{cite journal | vauthors = De Palma G, Nadal I, Collado MC, Sanz Y | title = Effects of a gluten-free diet on gut microbiota and immune function in healthy adult human subjects | journal = The British Journal of Nutrition | volume = 102 | issue = 8 | pages = 1154–60 | date = October 2009 | pmid = 19445821 | doi = 10.1017/S0007114509371767 | doi-access = free | hdl = 10261/15885 | hdl-access = free }}

{{Main|Non-celiac gluten sensitivity}}

Non-coeliac gluten sensitivity (NCGS) is described as a condition of multiple symptoms that improves when switching to a gluten-free diet, after coeliac disease and wheat allergy are excluded.{{cite journal | vauthors = Mooney PD, Aziz I, Sanders DS | title = Non-celiac gluten sensitivity: clinical relevance and recommendations for future research | journal = Neurogastroenterology and Motility | volume = 25 | issue = 11 | pages = 864–71 | date = November 2013 | pmid = 23937528 | doi = 10.1111/nmo.12216 | s2cid = 9277897 }}{{cite journal | vauthors = Nijeboer P, Bontkes HJ, Mulder CJ, Bouma G | title = Non-celiac gluten sensitivity. Is it in the gluten or the grain? | journal = Journal of Gastrointestinal and Liver Diseases | volume = 22 | issue = 4 | pages = 435–40 | date = December 2013 | pmid = 24369326 }} People with NCGS may develop gastrointestinal symptoms, which resemble those of irritable bowel syndrome (IBS){{cite journal | vauthors = Elli L, Roncoroni L, Bardella MT | title = Non-celiac gluten sensitivity: Time for sifting the grain | journal = World Journal of Gastroenterology | volume = 21 | issue = 27 | pages = 8221–6 | date = July 2015 | pmid = 26217073 | pmc = 4507091 | doi = 10.3748/wjg.v21.i27.8221 | type = Review | doi-access = free }}{{cite journal | vauthors = Catassi C, Bai JC, Bonaz B, Bouma G, Calabrò A, Carroccio A, Castillejo G, Ciacci C, Cristofori F, Dolinsek J, Francavilla R, Elli L, Green P, Holtmeier W, Koehler P, Koletzko S, Meinhold C, Sanders D, Schumann M, Schuppan D, Ullrich R, Vécsei A, Volta U, Zevallos V, Sapone A, Fasano A | display-authors = 6 | title = Non-Celiac Gluten sensitivity: the new frontier of gluten related disorders | journal = Nutrients | volume = 5 | issue = 10 | pages = 3839–53 | date = September 2013 | pmid = 24077239 | pmc = 3820047 | doi = 10.3390/nu5103839 | doi-access = free }} or a variety of nongastrointestinal symptoms.{{cite journal | vauthors = Volta U, Caio G, De Giorgio R, Henriksen C, Skodje G, Lundin KE | title = Non-celiac gluten sensitivity: a work-in-progress entity in the spectrum of wheat-related disorders | journal = Best Practice & Research. Clinical Gastroenterology | volume = 29 | issue = 3 | pages = 477–91 | date = June 2015 | pmid = 26060112 | doi = 10.1016/j.bpg.2015.04.006 }}{{cite journal | vauthors = Catassi C, Bai JC, Bonaz B, Bouma G, Calabrò A, Carroccio A, Castillejo G, Ciacci C, Cristofori F, Dolinsek J, Francavilla R, Elli L, Green P, Holtmeier W, Koehler P, Koletzko S, Meinhold C, Sanders D, Schumann M, Schuppan D, Ullrich R, Vécsei A, Volta U, Zevallos V, Sapone A, Fasano A | display-authors = 6 | title = Non-Celiac Gluten sensitivity: the new frontier of gluten related disorders | journal = Nutrients | volume = 5 | issue = 10 | pages = 3839–53 | date = September 2013 | pmid = 24077239 | pmc = 3820047 | doi = 10.3390/nu5103839 | type = Review | doi-access = free }}

Gastrointestinal symptoms may include any of the following: abdominal pain, bloating, bowel habit abnormalities (either diarrhea or constipation), nausea, aerophagia, gastroesophageal reflux disease, and aphthous stomatitis. A range of extra-intestinal symptoms, said to be the only manifestation of NCGS in the absence of gastrointestinal symptoms, have been suggested, but remain controversial.{{cite journal | vauthors = Aziz I, Hadjivassiliou M, Sanders DS | title = The spectrum of noncoeliac gluten sensitivity | journal = Nature Reviews. Gastroenterology & Hepatology | volume = 12 | issue = 9 | pages = 516–26 | date = September 2015 | pmid = 26122473 | doi = 10.1038/nrgastro.2015.107 | type = Review | s2cid = 2867448 }} These include: headache, migraine, "brain fog", fatigue, fibromyalgia,{{cite journal | vauthors = Rossi A, Di Lollo AC, Guzzo MP, Giacomelli C, Atzeni F, Bazzichi L, Di Franco M | title = Fibromyalgia and nutrition: what news? | journal = Clinical and Experimental Rheumatology | volume = 33 | issue = 1 Suppl 88 | pages = S117-25 | date = 2015 | pmid = 25786053 | type = Review }} joint and muscle pain, leg or arm numbness, tingling of the extremities, dermatitis (eczema or skin rash), atopic disorders such as asthma, rhinitis, other allergies, depression, anxiety, iron-deficiency anemia, folate deficiency or autoimmune diseases. NCGS has also been controversially implicated in some neuropsychiatric disorders, including schizophrenia, eating disorders, autism, peripheral neuropathy, ataxia and attention deficit hyperactivity disorder (ADHD). Above 20% of people with NCGS have IgE-mediated allergy to one or more inhalants, foods or metals, among which most common are mites, graminaceae, parietaria, cat or dog hair, shellfish and nickel. Approximately, 35% of people with NCGS have other food intolerances, mainly lactose intolerance.

The pathogenesis of NCGS is not yet well understood. For this reason, it is a controversial syndrome and some authors still question it.{{cite journal | vauthors = Fasano A, Sapone A, Zevallos V, Schuppan D | title = Nonceliac gluten sensitivity | journal = Gastroenterology | volume = 148 | issue = 6 | pages = 1195–204 | date = May 2015 | pmid = 25583468 | doi = 10.1053/j.gastro.2014.12.049 | type = Review | quote = One of the most controversial and highly debated discussions concerns the role of gluten in causing NCGS. Recent reports have indicated that gluten might not be the cause of NCGS, and some investigators still question whether NCGS as a real clinical entity. (...) Cereals such as wheat and rye, when consumed in normal quantities, are only minor sources of FODMAPs in the daily diet (Table 1). Therefore, gluten-containing grains are not likely to induce IBS exclusively via FODMAPs. In contrast, there is growing evidence that other proteins that are unique to gluten-containing cereals can elicit an innate immune response that leads to NCGS, raising a nomenclature issue. For this reason, wheat sensitivity, rather than gluten sensitivity, seems to be a more appropriate term, keeping in mind that other gluten-containing grains such as barley and rye also can trigger the symptoms. | doi-access = free }} There is evidence that not only gliadin (the main cytotoxic antigen of gluten), but also other proteins named ATIs which are present in gluten-containing cereals (wheat, rye, barley, and their derivatives) may have a role in the development of symptoms. ATIs are potent activators of the innate immune system.{{cite journal | vauthors = Fasano A, Sapone A, Zevallos V, Schuppan D | title = Nonceliac gluten sensitivity | journal = Gastroenterology | volume = 148 | issue = 6 | pages = 1195–204 | date = May 2015 | pmid = 25583468 | doi = 10.1053/j.gastro.2014.12.049 | type = Review | doi-access = free }} FODMAPs, especially fructans, are present in small amounts in gluten-containing grains and have been identified as a possible cause of some gastrointestinal symptoms in persons with NCGS.{{cite journal | vauthors = Ontiveros N, Hardy MY, Cabrera-Chavez F | title = Assessing of Celiac Disease and Nonceliac Gluten Sensitivity | journal = Gastroenterology Research and Practice | volume = 2015 | pages = 723954 | year = 2015 | pmid = 26064097 | pmc = 4429206 | doi = 10.1155/2015/723954 | type = Review | doi-access = free }} As of 2019, reviews have concluded that although FODMAPs may play a role in NCGS, they only explain certain gastrointestinal symptoms, such as bloating, but not the extra-digestive symptoms that people with NCGS may develop, such as neurological disorders, fibromyalgia, psychological disturbances, and dermatitis.

After exclusion of coeliac disease and wheat allergy,{{cite journal | vauthors = Mansueto P, Seidita A, D'Alcamo A, Carroccio A | title = Non-celiac gluten sensitivity: literature review | journal = Journal of the American College of Nutrition | volume = 33 | issue = 1 | pages = 39–54 | year = 2014 | pmid = 24533607 | doi = 10.1080/07315724.2014.869996 | hdl-access = free | type = Review | s2cid = 22521576 | hdl = 10447/90208 }} the subsequent step for diagnosis and treatment of NCGS is to start a strict gluten-free diet to assess if symptoms improve or resolve completely. This may occur within days to weeks of starting a GFD, but improvement may also be due to a non-specific, placebo response.{{cite journal | vauthors = Genuis SJ, Lobo RA | title = Gluten sensitivity presenting as a neuropsychiatric disorder | journal = Gastroenterology Research and Practice | volume = 2014 | pages = 293206 | year = 2014 | pmid = 24693281 | pmc = 3944951 | doi = 10.1155/2014/293206 | type = Review | doi-access = free }} Recommendations may resemble those for coeliac disease, for the diet to be strict and maintained, with no transgression. The degree of gluten cross contamination tolerated by people with NCGS is not clear but there is some evidence that they can present with symptoms even after consumption of small amounts. It is not yet known whether NCGS is a permanent or a transient condition. A trial of gluten reintroduction to observe any reaction after one–two years of strict gluten-free diet might be performed.

A subgroup of people with NCGS may not improve by eating commercially available gluten-free products, which are usually rich of preservatives and additives, because chemical additives (such as sulphites, glutamates, nitrates and benzoates) might have a role in evoking functional gastrointestinal symptoms of NCGS. These people may benefit from a diet with a low content of preservatives and additives.{{cite journal | vauthors = Volta U, Caio G, Tovoli F, De Giorgio R | title = Non-celiac gluten sensitivity: questions still to be answered despite increasing awareness | journal = Cellular & Molecular Immunology | volume = 10 | issue = 5 | pages = 383–92 | date = September 2013 | pmid = 23934026 | pmc = 4003198 | doi = 10.1038/cmi.2013.28 | type = Review }}

NCGS, which is possibly immune-mediated, now appears to be more common than coeliac disease,{{cite journal | vauthors = Hogg-Kollars S, Al Dulaimi D, Tait K, Rostami K | title = Type 1 diabetes mellitus and gluten induced disorders | journal = Gastroenterology and Hepatology from Bed to Bench | volume = 7 | issue = 4 | pages = 189–97 | year = 2014 | pmid = 25289132 | pmc = 4185872 | type = Review }} with prevalence rates between 0.5 and 13% in the general population.{{cite journal | vauthors = Molina-Infante J, Santolaria S, Sanders DS, Fernández-Bañares F | title = Systematic review: noncoeliac gluten sensitivity | journal = Alimentary Pharmacology & Therapeutics | volume = 41 | issue = 9 | pages = 807–20 | date = May 2015 | pmid = 25753138 | doi = 10.1111/apt.13155 | type = Review | s2cid = 207050854 | doi-access = free }}

{{Main|Wheat allergy}}

People can also experience adverse effects of wheat as result of a wheat allergy.Costantino A, Aversano GM, Lasagni G, Smania V, Doneda L, Vecchi M, Roncoroni L, Pastorello EA, Elli L. Diagnostic management of patients reporting symptoms after wheat ingestion. Front Nutr. 2022 Oct 6;9:1007007. doi: 10.3389/fnut.2022.1007007. PMID 36276818; PMCID: PMC9582535. Gastrointestinal symptoms of wheat allergy are similar to those of coeliac disease and non-coeliac gluten sensitivity, but there is a different interval between exposure to wheat and onset of symptoms. Other symptoms such as dermal reactions like as rashes or hyperpigmentation may also occur in some people. Wheat allergy has a fast onset (from minutes to hours) after the consumption of food containing wheat and could be anaphylaxis.{{cite journal | vauthors = Scherf KA, Brockow K, Biedermann T, Koehler P, Wieser H | title = Wheat-dependent exercise-induced anaphylaxis | journal = Clinical and Experimental Allergy | volume = 46 | issue = 1 | pages = 10–20 | date = January 2016 | pmid = 26381478 | doi = 10.1111/cea.12640 | quote = Wheat-dependent exercise-induced anaphylaxis (WDEIA) is a rare, but potentially severe food allergy exclusively occurring when wheat ingestion is accompanied by augmenting cofactors. (...) The most reliable prophylaxis of WDEIA is a gluten-free diet. In less severe cases, a strict limitation of wheat ingestion before exercise and avoidance of other cofactors may be sufficient. | s2cid = 25066563 }}

The management of wheat allergy consists of complete withdrawal of any food containing wheat and other gluten-containing cereals. Nevertheless, some people with wheat allergy can tolerate barley, rye or oats.{{cite journal | vauthors = Pietzak M | title = Celiac disease, wheat allergy, and gluten sensitivity: when gluten free is not a fad | journal = Journal of Parenteral and Enteral Nutrition | volume = 36 | issue = 1 Suppl | pages = 68S–75S | date = January 2012 | pmid = 22237879 | doi = 10.1177/0148607111426276 }}

File:Gluten ataxia eng.ogg

Gluten ataxia is an autoimmune disease triggered by the ingestion of gluten.{{cite journal | vauthors = Sapone A, Bai JC, Ciacci C, Dolinsek J, Green PH, Hadjivassiliou M, Kaukinen K, Rostami K, Sanders DS, Schumann M, Ullrich R, Villalta D, Volta U, Catassi C, Fasano A | display-authors = 6 | title = Spectrum of gluten-related disorders: consensus on new nomenclature and classification | journal = BMC Medicine | volume = 10 | pages = 13 | date = February 2012 | pmid = 22313950 | pmc = 3292448 | doi = 10.1186/1741-7015-10-13 | type = Review | doi-access = free }} With gluten ataxia, damage takes place in the cerebellum, the balance center of the brain that controls coordination and complex movements like walking, speaking and swallowing, with loss of Purkinje cells. People with gluten ataxia usually present gait abnormality or incoordination and tremor of the upper limbs. Gaze-evoked nystagmus and other ocular signs of cerebellar dysfunction are common. Myoclonus, palatal tremor, and opsoclonus-myoclonus may also appear.

Early diagnosis and treatment with a gluten-free diet 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.{{cite journal | vauthors = Mitoma H, Adhikari K, Aeschlimann D, Chattopadhyay P, Hadjivassiliou M, Hampe CS, Honnorat J, Joubert B, Kakei S, Lee J, Manto M, Matsunaga A, Mizusawa H, Nanri K, Shanmugarajah P, Yoneda M, Yuki N | display-authors = 6 | title = Consensus Paper: Neuroimmune Mechanisms of Cerebellar Ataxias | journal = Cerebellum | volume = 15 | issue = 2 | pages = 213–32 | date = April 2016 | pmid = 25823827 | pmc = 4591117 | doi = 10.1007/s12311-015-0664-x | type = Review }}

Gluten ataxia accounts for 40% of ataxias of unknown origin and 15% of all ataxias.{{cite journal | vauthors = Hadjivassiliou M, Sanders DD, Aeschlimann DP | title = Gluten-related disorders: gluten ataxia | journal = Digestive Diseases | volume = 33 | issue = 2 | pages = 264–8 | year = 2015 | pmid = 25925933 | doi = 10.1159/000369509 | type = Review | s2cid = 207673823 }}{{cite journal | vauthors = Hadjivassiliou M, Grünewald R, Sharrack B, Sanders D, Lobo A, Williamson C, Woodroofe N, Wood N, Davies-Jones A | display-authors = 6 | title = Gluten ataxia in perspective: epidemiology, genetic susceptibility and clinical characteristics | journal = Brain | volume = 126 | issue = Pt 3 | pages = 685–91 | date = March 2003 | pmid = 12566288 | doi = 10.1093/brain/awg050 | doi-access = free }} Less than 10% of people with gluten ataxia present any gastrointestinal symptom, yet about 40% have intestinal damage.

Since the beginning of the 21st century, the gluten-free diet has become the most popular fad diet in the United States and other countries. Clinicians worldwide have been challenged by an increasing number of people who do not have coeliac disease nor wheat allergy, with digestive or extra-digestive symptoms which improved removing wheat/gluten from the diet. Many of these persons began a gluten-free diet on their own, without having been previously evaluated.{{cite journal | vauthors = Volta U, Caio G, Karunaratne TB, Alaedini A, De Giorgio R | title = Non-coeliac gluten/wheat sensitivity: advances in knowledge and relevant questions | journal = Expert Review of Gastroenterology & Hepatology | volume = 11 | issue = 1 | pages = 9–18 | date = January 2017 | pmid = 27852116 | doi = 10.1080/17474124.2017.1260003 | type = Review | s2cid = 34881689 }} Another reason that contributed to this trend was the publication of several books that demonize gluten and point to it as a cause of type 2 diabetes, weight gain and obesity, and a broad list of diseases ranging from depression and anxiety to arthritis and autism.{{cite journal | vauthors = Shewry PR, Hey SJ | title = Do we need to worry about eating wheat? | journal = Nutrition Bulletin | volume = 41 | issue = 1 | pages = 6–13 | date = March 2016 | pmid = 26941586 | pmc = 4760426 | doi = 10.1111/nbu.12186 }} The book that has had the most impact is Grain Brain: The Surprising Truth About Wheat, Carbs, and Sugar—Your Brain's Silent Killers, by the American neurologist David Perlmutter, published in September 2013. Another book that has had great impact is Wheat Belly: Lose the Wheat, Lose the Weight, and Find Your Path Back to Health, by the cardiologist William Davis, which refers to wheat as a "chronic poison" and became a New York Times bestseller within a month of publication in 2011.{{cite web | author=David Quick | url=http://www.postandcourier.com/article/20120911/PC1211/120919931/1020/quick-column-wheat-belly-continues-its-run-on-nyt-best-seller-list-but-is-demonizing-wheat-and-gluten-justified | title='Wheat Belly' continues its run on NYT Best Seller list, but is demonizing wheat and gluten justified? | work=The Post and Courier | date= September 11, 2012 | access-date=December 16, 2012}} The gluten-free diet has been advocated and followed by many celebrities to lose weight, such as Miley Cyrus, Gwyneth Paltrow, and Kourtney Kardashian, and are used by some professional athletes, who believe the diet can improve energy and health.{{cite journal | vauthors = Lebwohl B, Ludvigsson JF, Green PH | title = Celiac disease and non-celiac gluten sensitivity | journal = BMJ | volume = 351 | pages = h4347 | date = October 2015 | pmid = 26438584 | pmc = 4596973 | doi = 10.1136/bmj.h4347 | quote = Some population groups seem to be especially wed to the gluten-free diet, with nearly 50% of 910 athletes (including world class and Olympic medalists) adhering to a gluten-free diet, mainly because of the perceived health and energy benefits. | type = Review }}{{cite journal | vauthors = Jones AL | title = The Gluten-Free Diet: Fad or Necessity? | journal = Diabetes Spectrum | volume = 30 | issue = 2 | pages = 118–123 | date = May 2017 | pmid = 28588378 | pmc = 5439366 | doi = 10.2337/ds16-0022 }}{{cite news|title=Is gluten-free a lifestyle or a diet craze?|url=https://www.usatoday.com/story/news/nation/2013/03/05/gluten-free-diet-popularity/1963715/|work=USA Today|date=5 March 2013|access-date=4 April 2018}}{{Cite web|url=http://www.instyle.com/celebrity/gluten-free-stars|title=Celebrities Who Are Gluten-Free|website=InStyle|access-date=April 6, 2018|archive-date=April 6, 2018|archive-url=https://web.archive.org/web/20180406102411/http://www.instyle.com/celebrity/gluten-free-stars|url-status=dead}} It became popular in the US, as the popularity of low-carbohydrate diets faded.{{Cite news |url=http://freakonomics.com/podcast/demonization-gluten/ |title=The Demonization of Gluten | vauthors = Dubner SJ |date=18 October 2017 |work=Freakonomics |access-date=2017-11-06|archive-url=https://web.archive.org/web/20171019055039/http://freakonomics.com/podcast/demonization-gluten/|archive-date=2017-10-19|url-status=dead|language=en-US}}

Estimates suggest that in 2014, 30% of people in the US and Australia were consuming gluten-free foods, with a growing number, calculated from surveys that by 2016 approximately 100 million Americans would consume gluten-free products.{{cite journal | vauthors = Nash DT, Slutzky AR | title = Gluten sensitivity: new epidemic or new myth? | journal = Proceedings | volume = 27 | issue = 4 | pages = 377–8 | date = October 2014 | pmid = 25484517 | pmc = 4255872 | doi = 10.1080/08998280.2014.11929164 }}{{cite news|title=An increasing number of Australians are choosing a gluten-free diet |url=http://www.heraldsun.com.au/news/national/an-increasing-number-of-australians-are-choosing-a-glutenfree-diet/news-story/55fe0b30277e721cc69f1eeb6191c130 |work=Herald Sun |date=18 November 2014|access-date=4 April 2018}} Data from a 2015 Nielsen survey of 30,000 adults in 60 countries around the world conclude that 21% of people prefer to buy gluten-free foods, being the highest interest among the younger generations.{{cite journal | vauthors = Reilly NR | title = The Gluten-Free Diet: Recognizing Fact, Fiction, and Fad | journal = The Journal of Pediatrics | volume = 175 | pages = 206–10 | date = August 2016 | pmid = 27185419 | doi = 10.1016/j.jpeds.2016.04.014 | doi-access = free }} In the US, it was estimated that more than half of people who buy foods labeled gluten-free do not have a clear reaction to gluten, and they do so "because they think it will help them lose weight, because they seem to feel better or because they mistakenly believe they are sensitive to gluten."{{cite web |url=https://www.cbsnews.com/news/gluten-free-diet-fad-are-celiac-disease-rates-actually-rising/ |title=Gluten-free diet fad: Are celiac disease rates actually rising? |publisher=CBS News |date=2012-07-31 |access-date=2013-12-06}} Although gluten is highly immunologically reactive and humans appear not to have evolved to digest it well, a gluten-free diet is not a healthier option for the general population, other than people with gluten-related disorders or other associated conditions which improve with a gluten-free diet in some cases, such as irritable bowel syndrome and certain autoimmune and neurological disorders.{{cite journal | vauthors = Gaesser GA, Angadi SS | title = Gluten-free diet: imprudent dietary advice for the general population? | journal = Journal of the Academy of Nutrition and Dietetics | volume = 112 | issue = 9 | pages = 1330–1333 | date = September 2012 | pmid = 22939437 | doi = 10.1016/j.jand.2012.06.009 | doi-access = free }} There is no published experimental evidence to support that the gluten-free diet contributes to weight loss.

In a review of May 2015 published in Gastroenterology, Fasano et al. conclude that, although there is an evident "fad component" to the recent rise in popularity of the gluten-free diet, there is also growing and unquestionable evidence of the existence of non-coeliac gluten sensitivity.{{cite journal | vauthors = Fasano A, Sapone A, Zevallos V, Schuppan D | title = Nonceliac gluten sensitivity | journal = Gastroenterology | volume = 148 | issue = 6 | pages = 1195–204 | date = May 2015 | pmid = 25583468 | doi = 10.1053/j.gastro.2014.12.049 | quote = Although there is clearly a fad component to the popularity of the GFD, there is also undisputable and increasing evidence for NCGS. | doi-access = free }}

In some cases, the popularity of the gluten-free diet may harm people who must eliminate gluten for medical reasons. For example, servers in restaurants may not take dietary requirements seriously, believing them to be merely a preference. This could prevent appropriate precautions in food handling to prevent gluten cross-contamination.{{cite web|title=The Consequences of a Gluten-Free Diet Craze|url=https://wheatfoundation.org/the-consequences-of-a-gluten-free-diet-craze/ |publisher=National Wheat Foundation|access-date=6 April 2018}} Medical professionals may also confuse medical explanations for gluten intolerance with patient preference. On the other hand, the popularity of the gluten-free diet has increased the availability of commercial gluten-free replacement products and gluten-free grains.

Gluten-free commercial replacement products, such as gluten-free cakes, are more expensive than their gluten-containing counterparts, so their purchase adds a financial burden. They are also typically higher in calories, fat, and sugar, and lower in dietary fibre. In less developed countries, wheat can represent an important source of protein, since it is a substantial part of the diet in the form of bread, noodles, bulgur, couscous, and other products.Shewry P.R. "Seed Proteins". In: Black M., Bewley J.D., editors. Seed Technology and Its Biological Basis. Sheffield Academic Press; Sheffield, UK: 2000. pp. 42–84.

In the British National Health Service, gluten-free foods have been supplied on prescription. For many patients, this meant at no cost. When it was proposed to alter this in 2018, the Department of Health and Social Care made an assessment of the costs and benefits. The potential annual financial saving to the service was estimated at £5.3 million, taking into account the reduction in cost spending and the loss of income from prescription charges. The proposed scenario was actually that patients could still be prescribed gluten-free breads and mixes but would have to buy any other gluten-free products themselves. The savings would only amount to £700,000 a year. Local initiatives by clinical commissioning groups had already reduced the cost of gluten-free foods to the NHS by 39% between 2015 and 2017.{{cite news |last1=Robinson |first1=Julia |title=Ending gluten-free prescribing entirely would have more health benefits and save more money, government assessment finds |url=https://pharmaceutical-journal.com/article/news/ending-gluten-free-prescribing-entirely-would-have-more-health-benefits-and-save-more-money-government-assessment-finds |access-date=4 March 2025 |work=The Pharmaceutical Journal |date=8 November 2018}}

Healthcare professionals recommend against undertaking a gluten-free diet as a form of self-diagnosis,{{cite web |url=http://oregon.providence.org/our-services/p/providence-nutrition-services/forms-and-information/three-reasons-to-go-gluten-free-and-three-reasons-not-to|title=Three Reasons to Go Gluten Free and Three Reasons Not to| vauthors = Lewis S |work=Related Forms & Information |publisher=Province Health & Services|access-date=30 March 2014}} because tests for coeliac disease are reliable only if the person has been consuming gluten recently. There is a consensus in the medical community that people should consult a physician before going on a gluten-free diet, so that a medical professional can accurately test for coeliac disease or any other gluten-induced health issues.{{cite journal | vauthors = Elli L, Branchi F, Tomba C, Villalta D, Norsa L, Ferretti F, Roncoroni L, Bardella MT | display-authors = 6 | title = Diagnosis of gluten related disorders: Celiac disease, wheat allergy and non-celiac gluten sensitivity | journal = World Journal of Gastroenterology | volume = 21 | issue = 23 | pages = 7110–9 | date = June 2015 | pmid = 26109797 | pmc = 4476872 | doi = 10.3748/wjg.v21.i23.7110 | type = Review | doi-access = free }}

Although popularly used as an alternative treatment for people with autism, there is no good evidence that a gluten-free diet is of benefit in reducing the symptoms of autism.

In a 2013 double-blind, placebo-controlled challenge (DBPC) by Biesiekierski et al. in a few people with irritable bowel syndrome, the authors found no difference between gluten or placebo groups and the concept of non-celiac gluten sensitivity as a syndrome was questioned. Nevertheless, this study had design errors and an incorrect selection of participants, and probably the reintroduction of both gluten and whey protein had a nocebo effect similar in all people, and this could have masked the true effect of gluten/wheat reintroduction.

In a 2015 double-blind placebo cross-over trial, small amounts of purified wheat gluten triggered gastrointestinal symptoms (such as abdominal bloating and pain) and extra-intestinal manifestations (such as foggy mind, depression and aphthous stomatitis) in self-reported non-celiac gluten sensitivity. Nevertheless, it remains elusive whether these findings specifically implicate gluten or other proteins present in gluten-containing cereals.

In a 2018 double-blind, crossover research study on 59 persons on a gluten-free diet with challenges of gluten, fructans or placebo, intestinal symptoms (specifically bloating) were borderline significantly higher after challenge with fructans, in comparison with gluten proteins (P=0.049).{{cite journal | vauthors = Verbeke K | title = Nonceliac Gluten Sensitivity: What Is the Culprit? | journal = Gastroenterology | volume = 154 | issue = 3 | pages = 471–473 | date = February 2018 | pmid = 29337156 | doi = 10.1053/j.gastro.2018.01.013 | quote = Although intolerance to fructans and other FODMAPs may contribute to NCGS, they may only explain gastrointestinal symptoms and not the extraintestinal symptoms observed in NCGS patients, such as neurologic dysfunction, psychological disturbances, fibromyalgia, and skin rash.15 Therefore, it is unlikely that they are the sole cause of NCGS. | doi-access = free }}{{cite journal | vauthors = Volta U, De Giorgio R, Caio G, Uhde M, Manfredini R, Alaedini A | title = Nonceliac Wheat Sensitivity: An Immune-Mediated Condition with Systemic Manifestations | journal = Gastroenterology Clinics of North America | volume = 48 | issue = 1 | pages = 165–182 | date = March 2019 | pmid = 30711208 | pmc = 6364564 | doi = 10.1016/j.gtc.2018.09.012 | type = Review | quote = Furthermore, a role for the FODMAP (eg, fructans) component of wheat as the sole trigger for symptoms is somewhat doubtful, because many patients with NCWS report resolution of symptoms after the withdrawal of wheat and related cereals, while continuing to ingest vegetables and fruits with high FODMAP content in their diets.59 On the whole, it is conceivable that more than one culprit may be involved in symptoms of NCWS (as they are currently defined), including gluten, other wheat proteins, and FODMAPs.60–62 }} Although the differences between the three interventions was very small, the authors concluded that fructans (the specific type of FODMAP found in wheat) are more likely to be the cause of gastrointestinal symptoms of non-celiac gluten sensitivity, rather than gluten. For this previous study, experts recommend a low FODMAP diet instead of a gluten free diet for those patients suffering from functional gastrointestinal disorders as bloating.Pessarelli T, Sorge A, Elli L, Costantino A. The low-FODMAP diet and the gluten-free diet in the management of functional abdominal bloating and distension. Front Nutr. 2022 Nov 8;9:1007716. doi: 10.3389/fnut.2022.1007716. PMID 36424920; PMCID: PMC9678936. In addition, fructans used in the study were extracted from chicory root, so it remains to be seen whether the wheat fructans produce the same effect.

File:Chenopodium quinoa0.jpg is a pseudocereal that is gluten-free.]]

File:Home made buckwheat bread.jpg

A gluten-free diet is a diet that strictly excludes gluten, proteins present in wheat (and all wheat varieties such as spelt and kamut), barley, rye, oat, and derivatives of these grains such as malt and triticale, and foods that may include them, or shared transportation or processing facilities with them. The inclusion of oats in a gluten-free diet remains controversial. Oat toxicity in people with gluten-related disorders depends on the oat cultivar consumed because the immunoreactivities of toxic prolamins are different among oat varieties. Furthermore, oats are frequently cross-contaminated with the other gluten-containing cereals. Pure oat (labelled as "pure oat" or "gluten-free oat") refers to oats uncontaminated with any of the other gluten-containing cereals.{{cite journal | vauthors = Comino I, Moreno MD, Sousa C | title = Role of oats in celiac disease | journal = World Journal of Gastroenterology | volume = 21 | issue = 41 | pages = 11825–31 | date = November 2015 | pmid = 26557006 | pmc = 4631980 | doi = 10.3748/wjg.v21.i41.11825 | quote = It is necessary to consider that oats include many varieties, containing various amino acid sequences and showing different immunoreactivities associated with toxic prolamins. As a result, several studies have shown that the immunogenicity of oats varies depending on the cultivar consumed. Thus, it is essential to thoroughly study the variety of oats used in a food ingredient before including it in a gluten-free diet. | doi-access = free }} Some cultivars of pure oat could be a safe part of a gluten-free diet, requiring knowledge of the oat variety used in food products for a gluten-free diet. Nevertheless, the long-term effects of pure oats consumption are still unclear{{cite journal | vauthors = Haboubi NY, Taylor S, Jones S | title = Coeliac disease and oats: a systematic review | journal = Postgraduate Medical Journal | volume = 82 | issue = 972 | pages = 672–8 | date = October 2006 | pmid = 17068278 | pmc = 2653911 | doi = 10.1136/pgmj.2006.045443 | type = Review }} and further studies identifying the cultivars used are needed before making final recommendations on their inclusion in the gluten-free diet.

Other grains, although gluten-free in themselves, may contain gluten by cross-contamination with gluten-containing cereals during grain harvesting, transporting, milling, storing, processing, handling or cooking.{{cite web|url=https://www.fsai.ie/uploadedfiles/legislation/consultations/info_270204.pdf|title=Guidelines to Prevent Cross-Contamination of Gluten-free Foods|publisher=Food Safety Authority of Ireland|access-date=Dec 20, 2015|url-status=dead|archive-url=https://web.archive.org/web/20160305013411/https://www.fsai.ie/uploadedfiles/legislation/consultations/info_270204.pdf|archive-date=March 5, 2016|df=mdy-all}}{{cite journal | vauthors = Comino I, Moreno MD, Real A, Rodríguez-Herrera A, Barro F, Sousa C | title = The gluten-free diet: testing alternative cereals tolerated by celiac patients | journal = Nutrients | volume = 5 | issue = 10 | pages = 4250–68 | date = October 2013 | pmid = 24152755 | pmc = 3820072 | doi = 10.3390/nu5104250 | doi-access = free }}

Processed foods commonly contain gluten as an additive (as emulsifiers, thickeners, gelling agents, fillers, and coatings), so they would need specific labeling. Unexpected sources of gluten are, among others, processed meat, vegetarian meat substitutes, reconstituted seafood, stuffings, butter, seasonings, marinades, dressings, confectionary, candies, and ice cream.

File:Gluten Free Rice Flour.jpg

Cross-contamination in the home is also a consideration for those who have gluten-related disorders.{{cite journal | vauthors = See JA, Kaukinen K, Makharia GK, Gibson PR, Murray JA | title = Practical insights into gluten-free diets | journal = Nature Reviews. Gastroenterology & Hepatology | volume = 12 | issue = 10 | pages = 580–91 | date = October 2015 | pmid = 26392070 | doi = 10.1038/nrgastro.2015.156 | type = Review | s2cid = 20270743 }} There can be many sources of cross-contamination, as for example when family members prepare gluten-free and gluten-containing foods on the same surfaces (countertops, tables, etc.) or share utensils that have not been cleaned after being used to prepare gluten-containing foods (cutting boards, colanders, cutlery, etc.), kitchen equipment (toaster, cupboards, etc.) or certain packaged foods (butter, peanut butter, etc.).

File:Gluten-free grocery store section.jpg

Restaurants prove to be another source of cross-contamination for those following a strict gluten-free diet. A study conducted by Columbia University Medical Center found that 32% of foods labeled gluten-free at restaurants contain above 20 parts per million of gluten, meaning that it contains enough gluten that it is no longer considered gluten-free by the Codex Alimentarius.{{Cite web|title=Gluten May Be Lurking in 'Gluten-Free' Restaurant Food|url=http://www.medscape.com/viewarticle/903083|access-date=2021-03-23|website=Medscape}} Cross-contamination occurs in these areas frequently because of a general lack of knowledge about the needed level of caution and the prevalence of gluten in restaurant kitchens.{{cite journal | vauthors = Verma AK, Gatti S, Galeazzi T, Monachesi C, Padella L, Baldo GD, Annibali R, Lionetti E, Catassi C | display-authors = 6 | title = Gluten Contamination in Naturally or Labeled Gluten-Free Products Marketed in Italy | journal = Nutrients | volume = 9 | issue = 2 | pages = 115 | date = February 2017 | pmid = 28178205 | pmc = 5331546 | doi = 10.3390/nu9020115 | doi-access = free }} If cooks are unaware of the severity of their guest's diet restrictions or of the important practices needed to limit cross-contamination, they can unknowingly deliver contaminated food. However, some restaurants utilize a training program for their employees to educate them about the gluten-free diet.{{Cite journal| vauthors = Mistry A, Tosto-Sheppard L |date=2020-06-01|title=Food Allergen and Gluten Training and Awareness Among Restaurant Workers Serving Gluten-Free Foods |journal=Current Developments in Nutrition|volume=4|issue=Supplement_2|pages=719|doi=10.1093/cdn/nzaa051_016|issn=2475-2991|pmc=7257391}} The accuracy of the training varies. One resource to find these safer restaurants is an app and website called "Find Me Gluten Free" that allows people following a gluten-free diet to rate the safety of different restaurants from their point of view and describe their experience to help future customers.

Easily locating gluten-free items is one of the main difficulties in following a gluten-free diet. To assist in this process, many restaurants and grocery stores choose to label food items. Restaurants often add a gluten-free section to their menu, or specifically mark gluten-free items with a symbol of some kind. Grocery stores often have a gluten-free aisle, or they will attach labels on the shelf underneath gluten-free items. Though the food is labeled gluten-free in this way, it does not necessarily mean that the food is safe for those with gluten-related disorders, as a compilation of studies suggest.{{cite journal | vauthors = Falcomer AL, Santos Araújo L, Farage P, Santos Monteiro J, Yoshio Nakano E, Puppin Zandonadi R | title = Gluten contamination in food services and industry: A systematic review | journal = Critical Reviews in Food Science and Nutrition | volume = 60 | issue = 3 | pages = 479–493 | date = 2020-02-04 | pmid = 30582343 | doi = 10.1080/10408398.2018.1541864 | s2cid = 58582062 | url = https://doi.org/10.1080/10408398.2018.1541864 }}

Medications and dietary supplements are made using excipients that may contain gluten.{{cite journal | vauthors = Cruz JE, Cocchio C, Lai PT, Hermes-DeSantis E | title = Gluten content of medications | journal = American Journal of Health-System Pharmacy | volume = 72 | issue = 1 | pages = 54–60 | date = January 2015 | pmid = 25511839 | doi = 10.2146/ajhp140153 }}

The gluten-free diet includes naturally gluten-free food, such as meat, fish, seafood, eggs, milk and dairy products, nuts, legumes, fruit, vegetables, potatoes, pseudocereals (in particular amaranth, buckwheat, chia seed, quinoa), only certain cereal grains (corn, rice, sorghum), minor cereals (including fonio, Job's tears, millet, teff, called "minor" cereals as they are "less common and are only grown in a few small regions of the world"),{{cite journal | vauthors = Saturni L, Ferretti G, Bacchetti T | title = The gluten-free diet: safety and nutritional quality | journal = Nutrients | volume = 2 | issue = 1 | pages = 16–34 | date = January 2010 | pmid = 22253989 | pmc = 3257612 | doi = 10.3390/nu2010016 | type = Review | doi-access = free }}. See Table 2 and page 21. some other plant products (arrowroot, mesquite flour,O'Brian T, Ford R, Kupper C, Celiac Disease and Non-Celiac Gluten Sensitivity: The evolving spectrum, pp. 305–330. In: {{cite book|author=Ingrid Kohlstadt|title=Advancing Medicine with Food and Nutrients, Second Edition|url=https://books.google.com/books?id=KhPSBQAAQBAJ&pg=PA318|date=10 December 2012|publisher=CRC Press|isbn=978-1-4398-8774-5|pages=318}} sago,{{cite journal | vauthors = Fletcher RF, McCRIRICK MY | title = Gluten-free diets | journal = British Medical Journal | volume = 2 | issue = 5091 | pages = 299–301 | date = August 1958 | pmid = 13560852 | pmc = 2026255 | doi = 10.1136/bmj.2.5091.299 }} tapioca) and products made from these gluten-free foods. Many Indian cuisine options, particularly South Indian cuisine, are gluten-free.{{Cite web|title=Venturing into Indian Cuisine|url=https://gluten.org/2020/01/15/venturing-into-indian-cuisine/|access-date=2022-07-27|website=Gluten Intolerance Group|date=January 15, 2020 }}

An unbalanced selection of food and an incorrect choice of gluten-free replacement products may lead to nutritional deficiencies. Replacing flour from wheat or other gluten-containing cereals with gluten-free flours in commercial products may lead to a lower intake of important nutrients, such as iron and B vitamins and a higher intake of sugars and saturated fats. Some gluten-free commercial replacement products are not enriched or fortified as their gluten-containing counterparts, and often have greater lipid / carbohydrate content. Children especially often over-consume these products, such as snacks and biscuits. These nutritional complications can be prevented by a correct dietary education. Pseudocereals (quinoa, amaranth, and buckwheat) and some minor cereals are healthy alternatives to these prepared products and have higher biological and nutritional value. Advances towards higher nutrition-content gluten-free bakery products, improved for example in terms of fiber content and glycemic index, have been made by using not exclusively corn starch or other starches to substitute for flour. In this aim, for example the dietary fibre inulin (which acts as a prebiotic{{cite journal | vauthors = Gibson GR, Roberfroid MB | title = Dietary modulation of the human colonic microbiota: introducing the concept of prebiotics | journal = The Journal of Nutrition | volume = 125 | issue = 6 | pages = 1401–12 | date = June 1995 | pmid = 7782892 | doi = 10.1093/jn/125.6.1401 | type = Review }}) or quinoa or amaranth wholemeal have been as substitute for part of the flour. Similarly, xanthan gum can be used in up to gram quantities per serving in some gluten-free baked goods and can be fermented by specific microbiomes in the gastrointestinal tract.{{cite web |title=Bob's Red Mill |url=https://www.bobsredmill.com/recipes/how-to-make/easy-gluten-free-pizza |website=Easy Gluten Free Pizza Recipe |access-date=9 April 2022}}{{cite journal |last1=Ostrowski |first1=Matthew P. |last2=La Rosa |first2=Sabina Leanti |last3=Kunath |first3=Benoit J. |last4=Robertson |first4=Andrew |last5=Pereira |first5=Gabriel |last6=Hagen |first6=Live H. |last7=Varghese |first7=Neha J. |last8=Qiu |first8=Ling |last9=Yao |first9=Tianming |last10=Flint |first10=Gabrielle |last11=Li |first11=James |last12=McDonald |first12=Sean P. |last13=Buttner |first13=Duna |last14=Pudlo |first14=Nicholas A. |last15=Schnizlein |first15=Matthew K. |last16=Young |first16=Vincent B. |last17=Brumer |first17=Harry |last18=Schmidt |first18=Thomas M. |last19=Terrapon |first19=Nicolas |last20=Lombard |first20=Vincent |last21=Henrissat |first21=Bernard |last22=Hamaker |first22=Bruce |last23=Eloe-Fadrosh |first23=Emiley A. |last24=Tripathi |first24=Ashootosh |last25=Pope |first25=Phillip B. |last26=Martens |first26=Eric C. |title=Mechanistic insights into consumption of the food additive xanthan gum by the human gut microbiota |journal=Nature Microbiology |date=April 2022 |volume=7 |issue=4 |pages=556–569 |doi=10.1038/s41564-022-01093-0| pmid=35365790|pmc=11537241 |s2cid=247866305 |hdl=11250/3003739 |hdl-access=free }} Such substitution has been found to also yield improved crust and texture of bread.{{cite journal|vauthors=Gallagher E, Gormley TR, Arendt EK|title=Recent advances in the formulation of gluten-free cereal-based products|journal=Trends in Food Science & Technology|volume=15|issue=3–4|year=2004|pages=143–152|issn=0924-2244|doi=10.1016/j.tifs.2003.09.012}} It is recommended that anyone embarking on a gluten-free diet check with a registered dietitian to make sure they are getting the required amount of key nutrients like iron, calcium, fiber, thiamin, riboflavin, niacin and folate. Vitamins often contain gluten as a binding agent. Experts have advised that it is important to always read the content label of any product that is intended to be swallowed.{{cite web|title=Gluten-free Diet|website=Mayo Clinic|url=http://www.mayoclinic.org/healthy-lifestyle/nutrition-and-healthy-eating/in-depth/gluten-free-diet/art-20048530|access-date=11 December 2016}}

Up to 30% of people with known coeliac disease often continue having or redeveloping symptoms.{{cite journal | vauthors = Rostom A, Murray JA, Kagnoff MF | title = American Gastroenterological Association (AGA) Institute technical review on the diagnosis and management of celiac disease | journal = Gastroenterology | volume = 131 | issue = 6 | pages = 1981–2002 | date = December 2006 | pmid = 17087937 | doi = 10.1053/j.gastro.2006.10.004 | url = http://www.gastrojournal.org/article/S0016-5085%2806%2902227-X/fulltext | type = Review | doi-access = free }} Also, a lack of symptoms or negative blood antibodies levels are not reliable indicators of intestinal recuperation. Several studies show an incomplete recovery of small bowel despite a strict gluten-free diet, and about 79% of such people have persistent villous atrophy. This lack of recovery is mainly caused by inadvertent exposure to gluten. People with poor basic education and understanding of the gluten-free diet often believe that they are strictly following the diet, but are making regular errors. In addition, some people often deliberately continue eating gluten because of limited availability, inferior taste, higher price, and inadequate labelling of gluten-free products. Poor compliance with the regimen is also influenced by age at diagnosis (adolescents), ignorance of the consequences of the lack of a strict treatment and certain psychological factors. Ongoing gluten intake can cause severe disease complications, such as various types of cancers (both intestinal and extra-intestinal) and osteoporosis.

The term gluten-free is generally used to indicate a supposed harmless level of gluten rather than a complete absence.{{cite journal | vauthors = Akobeng AK, Thomas AG | title = Systematic review: tolerable amount of gluten for people with coeliac disease | journal = Alimentary Pharmacology & Therapeutics | volume = 27 | issue = 11 | pages = 1044–52 | date = June 2008 | pmid = 18315587 | doi = 10.1111/j.1365-2036.2008.03669.x | s2cid = 20539463 | doi-access = free }} The exact level at which gluten is harmless is uncertain and controversial. A 2008 systematic review tentatively concluded that consumption of less than 10 mg of gluten per day is unlikely to cause histological abnormalities, although it noted that few reliable studies had been done.

Regulation of the label gluten-free varies by country. Most countries derive key provisions of their gluten-free labelling regulations from the Codex Alimentarius international standards for food labelling as a standard relating to the labelling of products as gluten-free. It only applies to foods that would normally contain gluten.{{cite web|url=http://www.codexalimentarius.org/download/standards/291/cxs_118e.pdf|publisher=Codex Alimentarius|title=Codex Standard For "Gluten-Free Foods" CODEX STAN 118-1981|date=February 22, 2006}} Gluten-free is defined as 20 ppm (= 20 mg/kg) or less. It categorizes gluten-free food as:

• Food that is gluten-free by composition
• Food that has become gluten-free through special processing.
• Reduced gluten content, food which includes food products with between 20 and 100 ppm of gluten Reduced gluten content is left up to individual nations to more specifically define.

The Codex Standard suggests the enzyme-linked Immunoassay (ELISA) R5 Mendez method for indicating the presence of gluten, but allows for other relevant methods, such as DNA. The Codex Standard specifies that the gluten-free claim must appear in the immediate proximity of the name of the product, to ensure visibility.

There is no general agreement on the analytical method used to measure gluten in ingredients and food products.{{cite journal | vauthors = Hischenhuber C, Crevel R, Jarry B, Mäki M, Moneret-Vautrin DA, Romano A, Troncone R, Ward R | display-authors = 6 | title = Review article: safe amounts of gluten for patients with wheat allergy or coeliac disease | journal = Alimentary Pharmacology & Therapeutics | volume = 23 | issue = 5 | pages = 559–75 | date = March 2006 | pmid = 16480395 | doi = 10.1111/j.1365-2036.2006.02768.x | s2cid = 9970042 | doi-access = free }} The ELISA method was designed to detect w-gliadins, but it suffered from the setback that it lacked sensitivity for barley prolamins.{{cite journal | vauthors = Poms RE, Klein CL, Anklam E | title = Methods for allergen analysis in food: a review | journal = Food Additives and Contaminants | volume = 21 | issue = 1 | pages = 1–31 | date = January 2004 | pmid = 14744677 | doi = 10.1080/02652030310001620423 | s2cid = 34705999 }} The use of highly sensitive assays is mandatory to certify gluten-free food products. The European Union, World Health Organization, and Codex Alimentarius require reliable measurement of the wheat prolamins, gliadins rather than all-wheat proteins.Codex Alimentarius (2003) Draft revised standards for gluten-free foods, report of the 25th session of the Codex Committee on Nutrition and Foods for Special Dietary Uses, November 2003

The Australian government recommends{{cite web|title=FINAL ASSESSMENT REPORT PROPOSAL P264 REVIEW OF GLUTEN CLAIMS WITH SPECIFIC REFERENCE TO OATS AND MALT|url=http://www.foodstandards.gov.au/code/proposals/Documents/P264%20Gluten%20Claims%20FAR.doc|publisher=Australian Government|access-date=9 August 2014}} that:

• food labelled gluten-free include no detectable gluten (<3ppm {{cite web|title=SUBMISSION FROM COELIAC AUSTRALIA|url=http://www.agriculture.gov.au/ag-farm-food/food/publications/national_food_plan/issues-paper/submissions-received/coeliac-australia??wasRedirectedByModule=true}}) oats or their products, cereals containing gluten that have been malted or their products
• food labelled low gluten claims such that the level of 20 mg gluten per 100 g of the food

All food products must be clearly labelled whether they contain gluten or they are gluten-free.{{cite web|title=Rotulagem de alimentos Alergênicos|url=http://portal.anvisa.gov.br/documents/33916/2810640/Rotulagem+de+Alerg%C3%AAnicos/283b1a22-d923-4eb1-84fa-cb1a662b7846|publisher=Agência Nacional de Vigilância Sanitária (ANVISA)|date=7 June 2017|access-date=7 April 2018|language=pt}} Since April 2016, the declaration of the possibility of cross-contamination is mandatory when the product does not intentionally add any allergenic food or its derivatives, but the Good Manufacturing Practices and allergen control measures adopted are not sufficient to prevent the presence of accidental trace amounts.{{cite web|title=Agência Nacional de Vigilância Sanitária Guia sobre Programa de Controle de Alergênicos|url=https://www.saude.rj.gov.br/comum/code/MostrarArquivo.php?C=MzIxOQ%2C%2C|publisher=Agência Nacional de Vigilância Sanitária (ANVISA)|date=2016|access-date=7 April 2018|language=pt|archive-url=https://web.archive.org/web/20180429222652/https://www.saude.rj.gov.br/comum/code/MostrarArquivo.php?C=MzIxOQ,,|archive-date=April 29, 2018|url-status=dead}} When a product contains the warning of cross-contamination with wheat, rye, barley, oats and their hybridized strains, the warning "contains gluten" is mandatory. The law does not establish a gluten threshold for the declaration of its absence.

Health Canada considers that foods containing levels of gluten not exceeding 20 ppm as a result of contamination, meet the health and safety intent of section B.24.018 of the Food and Drug Regulations when a gluten-free claim is made.{{cite web|title=Health Canada's Position on Gluten-Free Claims|url=http://www.hc-sc.gc.ca/fn-an/securit/allerg/cel-coe/gluten-position-eng.php|publisher=Health Canada|access-date=9 August 2014|date=December 2010}} Any intentionally added gluten, even at low levels must be declared on the packaging and a gluten-free claim would be considered false and misleading. Labels for all food products sold in Canada must clearly identify the presence of gluten if it is present at a level greater than 10 ppm.{{Cite web |url=http://www.celiac.ca/index.php/about-celiac-disease/food-labelling/ |title=Canadian Celiac Association |access-date=August 10, 2014 |archive-url=https://web.archive.org/web/20131201234621/http://www.celiac.ca/index.php/about-celiac-disease/food-labelling/ |archive-date=December 1, 2013 |url-status=dead }}

The EU European Commission delineates{{cite web|title=Gluten-free food|publisher=Directorate-General for Health and Consumers|access-date=25 July 2015|url=http://ec.europa.eu/food/safety/labelling_nutrition/special_groups_food/gluten/index_en.htm}} the categories as:

• gluten-free: 20 ppm or less of gluten
• very low gluten foodstuffs: 20-100ppm gluten.

All foods containing gluten as an ingredient must be labelled accordingly as gluten is defined as one of the 14 recognized EU allergens.{{cite web|url=https://www.food.gov.uk/science/allergy-intolerance/label/labelling-changes|title=EU Food Information for Consumers Regulation (EU FIC) |date=March 2016|publisher=Food Standards Agency|format=link}}

Until 2012 anyone could use the gluten-free claim with no repercussion.{{Cite web|url=https://www.medicalnewstoday.com/articles/315846|title=Gluten-free diet may have 'unintended consequences' for health|website=www.medicalnewstoday.com|date=February 15, 2017|language=en|access-date=2020-02-21}}{{Cite web|url=https://www.theatlantic.com/health/archive/2012/01/a-gluten-free-diet-reality-check/250750/|title=A Gluten-Free Diet Reality Check| vauthors = Fontenot B |date=2012-01-03|website=The Atlantic|language=en-US|access-date=2020-02-21}} In 2008, Wellshire Farms chicken nuggets labelled gluten-free were purchased and samples were sent to a food allergy laboratory{{cite news|url=http://www.chicagotribune.com/health/chi-081120-allergens-tribune-investigation,0,4610982.story|title=Children at risk in food roulette|work=Chicagotribune.com|access-date=September 20, 2009 | vauthors = Roe S }} where they were found to contain gluten. After this was reported in the Chicago Tribune, the products continued to be sold. The manufacturer has since replaced the batter used in its chicken nuggets.{{cite news |url=http://www.chicagotribune.com/news/nationworld/chi-whole_foodsdec31,0,4055580.story|title=Whole Foods pulls 'gluten-free' products from shelves after Tribune story|work=Chicagotribune.com|access-date=September 20, 2009 | vauthors = Roe S }} The U.S. first addressed gluten-free labelling in the 2004 Food Allergen Labeling and Consumer Protection Act (FALCPA). The Alcohol and Tobacco Tax and Trade Bureau published interim rules and proposed mandatory labelling for alcoholic products in 2006.{{USFR|71|42260}} (26 July 2006), {{USFR|71|42329}} (26 July 2006) The FDA issued their Final Rule on August 5, 2013.{{USFR|78|47154}} (5 August 2013). Codified at {{USCFR|21|101|91}}.

When a food producer voluntarily chooses to use a gluten-free claim for a product, the food bearing the claim in its labelling may not contain:

• an ingredient that is a gluten-containing grain
• an ingredient that is derived from a gluten-containing grain that has not been processed to remove gluten
• an ingredient that is derived from a gluten-containing grain, that has been processed to remove gluten but results in the presence of 20 ppm or more gluten in the food. Any food product claiming to be gluten-free and also bearing the term "wheat" in its ingredient list or in a separate "Contains wheat" statement, must also include the language "*the wheat has been processed to allow this food to meet the FDA requirements for gluten-free foods," in close proximity to the ingredient statement.

Any food product that inherently does not contain gluten may use a gluten-free label where any unavoidable presence of gluten in the food bearing the claim in its labelling is below 20 ppm gluten.

{{Portal|Food|Medicine}}

• 2010s in food
• Gluten-free, casein-free diet
• List of diets
• Paleolithic diet
• Specific carbohydrate diet

{{-}}

{{Reflist}}

• {{commonscat-inline}}

{{Wiktionary|Gluten-Free}}

{{Cookbook|Gluten-Free}}

• [https://www.mayoclinic.org/healthy-lifestyle/nutrition-and-healthy-eating/in-depth/gluten-free-diet/art-20048530 Gluten-free diet] by the Mayo Clinic

{{Gluten sensitivity|state=expanded}}

{{Irritable bowel syndrome}}

{{Fad diets}}

{{Diets}}

{{Authority control}}

Category:2010s in food

Category:Fad diets