Gluten and wheat sensitivities – An overview Scherf, Katharina Anne; Koehler, Peter; Wieser, Herbert
Journal of cereal science,
January 2016, 2016-01-00, Letnik:
67
Journal Article
Recenzirano
Wheat products are important staple foods worldwide. However, a small portion of the population has to avoid wheat-containing foods because of harmful immune responses. Countless studies have ...demonstrated that the storage (gluten) proteins of wheat are major causative agents for wheat-dependent immune-mediated disorders. The unique structural features of gluten proteins are long repetitive amino acid sequences rich in glutamine and proline. These sequence sections are involved in most wheat sensitivities. Corresponding homologous sequence sections of rye and barley proteins may also be harmful, but relevant studies are rare. Wheat sensitivities can be classified into three main forms: autoimmunogenic sensitivities including coeliac disease, dermatitis herpetiformis, and gluten ataxia; allergic sensitivities including immediate wheat allergy, wheat-dependent exercise-induced anaphylaxis, respiratory allergy, and contact urticaria; and non-coeliac gluten sensitivity. The presented overview summarizes our current knowledge of gluten protein structures related to wheat sensitivities and the epidemiological, clinical, and pathogenic differences between these immune-mediated disorders.
•Worldwide, wheat is an important source of carbohydrates, vitamins and minerals.•Gluten proteins of wheat are major causative agents for food sensitivities.•Relationships between gluten structures and wheat sensitivities are explained.•Clinical features, diagnosis and treatment of wheat sensitivities are delineated.
The technological properties of the ancient wheat species spelt, emmer and einkorn are considered inferior compared to common wheat and durum wheat, but there are only few comparative studies between ...ancient and modern wheat species. To help fill this gap, protein content and composition, gluten aggregation, dough and bread properties were determined in a unique set of eight cultivars each of common wheat, spelt, durum wheat, emmer and einkorn grown under standardized conditions at one location in the same year. Spearman correlations and principal component analysis (PCA) revealed that especially the contents of glutenins, high-molecular-weight glutenin subunits and glutenin macropolymer were suitable to predict the volume of breads made from wholemeal flours of the five wheat species using microbaking tests. Based on their proximity to common wheat in the PCA, one cultivar each of spelt, emmer and einkorn was identified that had similar protein analytical, functional and baking properties to common wheat. Furthermore, the characterization of gluten aggregation behavior using the GlutoPeak test (GPT) enabled an estimation of dough properties and bread volume. Therefore, the fast and easy GPT may serve as an alternative to time-consuming and labor-intensive baking tests.
•A unique set of eight cultivars of wheat, spelt, wheat, emmer and einkorn was compared.•Quality parameters to predict the baking quality of wholemeal flours were defined.•Contents of polymeric gluten proteins were good predictors of the baking quality.•Spelt, emmer and einkorn cultivars with good baking quality were identified by PCA.•The GlutoPeak test enabled an estimation of dough properties and bread volume.
Ingestion of wheat, barley, or rye triggers small intestinal inflammation in patients with celiac disease. Specifically, the storage proteins of these cereals (gluten) elicit an adaptive Th1-mediated ...immune response in individuals carrying HLA-DQ2 or HLA-DQ8 as major genetic predisposition. This well-defined role of adaptive immunity contrasts with an ill-defined component of innate immunity in celiac disease. We identify the α-amylase/trypsin inhibitors (ATIs) CM3 and 0.19, pest resistance molecules in wheat, as strong activators of innate immune responses in monocytes, macrophages, and dendritic cells. ATIs engage the TLR4-MD2-CD14 complex and lead to up-regulation of maturation markers and elicit release of proinflammatory cytokines in cells from celiac and nonceliac patients and in celiac patients' biopsies. Mice deficient in TLR4 or TLR4 signaling are protected from intestinal and systemic immune responses upon oral challenge with ATIs. These findings define cereal ATIs as novel contributors to celiac disease. Moreover, ATIs may fuel inflammation and immune reactions in other intestinal and nonintestinal immune disorders.
The diagnosis of celiac disease (CD) is complex and requires a multi-step procedure (symptoms, serology, duodenal biopsy, effect of a gluten-free diet, and optional genetic). The aim of the study was ...to contribute to the improvement of CD diagnosis by preparing a water-soluble gluten peptide fraction (called Solgluten) and by selecting gluten-specific enzyme-linked immunosorbent assays (ELISA) for the detection of gluten immunogenic gluten peptides (GIPs) in urine and blood serum spiked with Solgluten. Food-grade Solgluten was prepared by the extraction of a peptic digest of vital gluten with water, centrifugation, and freeze-drying. The process was relatively easy, repeatable, and cheap. The content of gliadin-derived GIPs was 491 mg/g. Solgluten was used as antigenic material to compare two competitive ELISA kits (R7021 and K3012) and two sandwich ELISA kits (M2114 and R7041) in their quality regarding the quantitation of GIPs in urine and blood serum. The quality parameters were the reactivity, sensitivity, coefficients of variation and determination, and curve shape. The evaluation of the kits showed a number of discrepancies in individual quality parameters measured in urine and serum. Due to the lowest limit of quantitation and the highest coefficient of determination, M2114 may be the first choice, while R7021 appeared to be less suitable because of the high coefficients of variation and unfavorable curve progression. The results set the stage for improving CD diagnosis by supplementing conventional blood tests with oral provocation with Solgluten and subsequent ELISA measurement of GIPs that could support the no-biopsy approach and by better assessing the effect of a gluten-free diet by monitoring adherence to the diet by measuring GIPs in urine and blood.
Millions of children and adults worldwide suffer from undiagnosed and untreated celiac disease (CeD). The clinical picture of CeD is highly heterogeneous and comprises manifestations that can affect ...almost the whole body. This narrative overview is aimed at characterizing diseases and complaints that are associated with unrecognized CeD and that frequently involve sites other than the gastrointestinal (G.I.) tract, i.e., dental, otorhinolaryngological, and ocular complications; skin and hair abnormalities; afflictions of the bones, joints, and muscles; cardiovascular affectations; kidney diseases; neuro-psychiatric disorders; and gynecological–obstetrical manifestations. The association between CeD and extra-GI manifestations is frequently overlooked, which leads to a delay in diagnosis. Most CeD-mediated disorders can be treated with a strict gluten-free diet (GFD), but some of them are irreversible unless CeD is diagnosed in time. Some manifestations can be classified as risk factors for CeD, and CeD screening tests for affected patients should be selectively considered. Apart from gastroenterologists, specialists in other medical disciplines can play an important role in identifying people with unrecognized CeD and may help prevent its progress and long-term complications. Further comprehensive investigations are necessary to clarify the pathogenesis of extra-GI manifestations and the effect of a GFD.
A gluten-free diet (GFD) is currently the only effective treatment for celiac disease (CD); an individual’s daily intake of gluten should not exceed 10 mg. However, it is difficult to maintain a ...strict oral diet for life and at least one-third of patients with CD are exposed to gluten, despite their best efforts at dietary modifications. It has been demonstrated that both natural and certified gluten-free foods can be heavily contaminated with gluten well above the commonly accepted threshold of 20 mg/kg. Moreover, meals from food services such as restaurants, workplaces, and schools remain a significant risk for inadvertent gluten exposure. Other possible sources of gluten are non-certified oat products, numerous composite foods, medications, and cosmetics that unexpectedly contain “hidden” vital gluten, a proteinaceous by-product of wheat starch production. A number of immunochemical assays are commercially available worldwide to detect gluten. Each method has specific features, such as format, sample extraction buffers, extraction time and temperature, characteristics of the antibodies, recognition epitope, and the reference material used for calibration. Due to these differences and a lack of official reference material, the results of gluten quantitation may deviate systematically. In conclusion, incorrect gluten quantitation, improper product labeling, and poor consumer awareness, which results in the inadvertent intake of relatively high amounts of gluten, can be factors that compromise the health of patients with CD.
Celiac disease (CD) is a chronic gluten-responsive immune mediated enteropathy and is treated with a gluten-free diet (GFD). However, a strict diet for life is not easy due to the ubiquitous nature ...of gluten. This review aims at examining available evidence on the degree of adherence to a GFD, the methods to assess it, and the barriers to its implementation. The methods for monitoring the adherence to a GFD are comprised of a dietary questionnaire, celiac serology, or clinical symptoms; however, none of these methods generate either a direct or an accurate measure of dietary adherence. A promising advancement is the development of tests that measure gluten immunogenic peptides in stools and urine. Causes of adherence/non-adherence to a GFD are numerous and multifactorial. Inadvertent dietary non-adherence is more frequent than intentional non-adherence. Cross-contamination of gluten-free products with gluten is a major cause of inadvertent non-adherence, while the limited availability, high costs, and poor quality of certified gluten-free products are responsible for intentionally breaking a GFD. Therefore, several studies in the last decade have indicated that many patients with CD who follow a GFD still have difficulty controlling their diet and, therefore, regularly consume enough gluten to trigger symptoms and damage the small intestine.
This review summarizes recent investigations on dental manifestations in celiac disease. Particular attention is paid to delayed dental eruption and maturity, dental enamel defects, molar incisor ...hypomineralization, dental caries, dental plaque, and periodontitis. Most studies confirmed a higher frequency of delayed dental eruption and maturation in children and dental enamel defects in children and adults with celiac disease compared to healthy individuals. The malabsorption of various micronutrients, especially calcium and vitamin D, as well as immunity, is considered the main cause of these conditions. An early diagnosis of celiac disease and introducing a gluten-free diet might prevent the development of these conditions. Otherwise, the damage has already been established, and it is irreversible. Dentists can play an important role in identifying people who may have unrecognized celiac disease and may help prevent its progress and long-term complications. Investigations on dental caries, plaque, and periodontitis in celiac disease are rare and inconsistent; these complaints need further examination.
Chemistry of gluten proteins Wieser, H
Food microbiology,
04/2007, Letnik:
24, Številka:
2
Journal Article, Conference Proceeding
Recenzirano
Gluten proteins play a key role in determining the unique baking quality of wheat by conferring water absorption capacity, cohesivity, viscosity and elasticity on dough. Gluten proteins can be ...divided into two main fractions according to their solubility in aqueous alcohols: the soluble gliadins and the insoluble glutenins. Both fractions consist of numerous, partially closely related protein components characterized by high glutamine and proline contents. Gliadins are mainly monomeric proteins with molecular weights (MWs) around 28,000-55,000 and can be classified according to their different primary structures into the α/β-, γ- and ω-type. Disulphide bonds are either absent or present as intrachain crosslinks. The glutenin fraction comprises aggregated proteins linked by interchain disulphide bonds; they have a varying size ranging from about 500,000 to more than 10 million. After reduction of disulphide bonds, the resulting glutenin subunits show a solubility in aqueous alcohols similar to gliadins. Based on primary structure, glutenin subunits have been divided into the high-molecular-weight (HMW) subunits (MW=67,000-88,000) and low-molecular-weight (LMW) subunits (MW=32,000-35,000). Each gluten protein type consists or two or three different structural domains; one of them contains unique repetitive sequences rich in glutamine and proline. Native glutenins are composed of a backbone formed by HMW subunit polymers and of LMW subunit polymers branched off from HMW subunits. Non-covalent bonds such as hydrogen bonds, ionic bonds and hydrophobic bonds are important for the aggregation of gliadins and glutenins and implicate structure and physical properties of dough.
Celiac disease (CeD) is a chronic gluten-sensitive immune-mediated enteropathy characterized by numerous intestinal and extra-intestinal signs and symptoms. Among extra-intestinal manifestations, ...otorhinolaryngological (ORL) complaints in CeD are relatively rare and their relation to CeD is frequently overlooked by physicians. Recent studies underlined that the prevalence of recurrent aphthous stomatitis, aphthous ulcers, geographic tongue, and xerostomia was significantly increased in CeD patients compared with healthy individuals. However, data about the other oral manifestations of CeD, such as atrophic glossitis, glossodynia, angular cheilitis, and salivary abnormalities, are scanty. Further ORL conditions associated with CeD include sensorineural hearing loss, nasal abnormalities, and obstructive sleep apnea. Moreover, several esophageal disorders such as gastroesophageal reflux disease and eosinophilic esophagitis have been associated with CeD. The pathophysiological link between both ORL and esophageal manifestations and CeD might be further investigated. In addition, also the role of gluten-free diet in improving these conditions is largely unclear. Certainly, otorhinolaryngologists can play an important role in identifying people with unrecognized CeD and may help prevent its long-term complications. The aim of this narrative review is to analyze the latest evidence on the association between CeD and ORL and esophageal manifestations.
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