Concept: Wheat allergy
Wheat gluten and related proteins can trigger an autoimmune enteropathy, known as coeliac disease, in people with genetic susceptibility. However, some individuals experience a range of symptoms in response to wheat ingestion, without the characteristic serological or histological evidence of coeliac disease. The aetiology and mechanism of these symptoms are unknown, and no biomarkers have been identified. We aimed to determine if sensitivity to wheat in the absence of coeliac disease is associated with systemic immune activation that may be linked to an enteropathy.
Coeliac disease (CD) incidence has increased in recent decades, characterised by variations according to sex, age at diagnosis, year of birth, month of birth and region of birth. Genetic susceptibility and exposure to gluten are the necessary factors in CD aetiology, although several environmental factors are considered.
Non Celiac Gluten sensitivity (NCGS) was originally described in the 1980s and recently a “re-discovered” disorder characterized by intestinal and extra-intestinal symptoms related to the ingestion of gluten-containing food, in subjects that are not affected with either celiac disease (CD) or wheat allergy (WA). Although NCGS frequency is still unclear, epidemiological data have been generated that can help establishing the magnitude of the problem. Clinical studies further defined the identity of NCGS and its implications in human disease. An overlap between the irritable bowel syndrome (IBS) and NCGS has been detected, requiring even more stringent diagnostic criteria. Several studies suggested a relationship between NCGS and neuropsychiatric disorders, particularly autism and schizophrenia. The first case reports of NCGS in children have been described. Lack of biomarkers is still a major limitation of clinical studies, making it difficult to differentiate NCGS from other gluten related disorders. Recent studies raised the possibility that, beside gluten, wheat amylase-trypsin inhibitors and low-fermentable, poorly-absorbed, short-chain carbohydrates can contribute to symptoms (at least those related to IBS) experienced by NCGS patients. In this paper we report the major advances and current trends on NCGS.
Abstract In response to the suggestion that an increase in the incidence of celiac disease might be attributable to an increase in the gluten content of wheat resulting from wheat breeding, a survey of data from the 20th and 21st centuries for the U.S. was carried out. The results do not support the likelihood that wheat breeding has increased the protein content (proportional to gluten content) of wheat in the U.S. Possible roles for changes in the per capita consumption of wheat flour and the use of vital gluten as a food additive are discussed.
Non-celiac gluten sensitivity (NCGS) is a syndrome diagnosed in patients with symptoms that respond to removal of gluten from the diet, after celiac disease and wheat allergy have been excluded. NCGS has been related to neuro-psychiatric disorders, such as autism, schizophrenia and depression. A singular report of NCGS presenting with hallucinations has been described in an adult patient. We report a pediatric case of a psychotic disorder clearly related to NCGS and investigate the causes by a review of literature. The pathogenesis of neuro-psychiatric manifestations of NCGS is unclear. It has been hypothesized that: (a) a “leaky gut” allows some gluten peptides to cross the intestinal membrane and the blood brain barrier, affecting the endogenous opiate system and neurotransmission; or (b) gluten peptides may set up an innate immune response in the brain similar to that described in the gut mucosa, causing exposure from neuronal cells of a transglutaminase primarily expressed in the brain. The present case-report confirms that psychosis may be a manifestation of NCGS, and may also involve children; the diagnosis is difficult with many cases remaining undiagnosed. Well-designed prospective studies are needed to establish the real role of gluten as a triggering factor in neuro-psychiatric disorders.
Background: Intestinal exposure to gliadin leads to zonulin upregulation and consequent disassembly of intercellular tight junctions and increased intestinal permeability. We aimed to study response to gliadin exposure, in terms of barrier function and cytokine secretion, using intestinal biopsies obtained from four groups: celiac patients with active disease (ACD), celiac patients in remission (RCD), non-celiac patients with gluten sensitivity (GS) and non-celiac controls (NC). Methods: Ex-vivo human duodenal biopsies were mounted in microsnapwells and luminally incubated with either gliadin or media alone. Changes in transepithelial electrical resistance were monitored over 120 min. Media was subsequently collected and cytokines quantified. Results: Intestinal explants from all groups (ACD (n = 6), RCD (n = 6), GS (n = 6), and NC (n = 5)) demonstrated a greater increase in permeability when exposed to gliadin vs. media alone. The increase in permeability in the ACD group was greater than in the RCD and NC groups. There was a greater increase in permeability in the GS group compared to the RCD group. There was no difference in permeability between the ACD and GS groups, between the RCD and NC groups, or between the NC and GS groups. IL-10 was significantly greater in the media of the NC group compared to the RCD and GS groups. Conclusions: Increased intestinal permeability after gliadin exposure occurs in all individuals. Following gliadin exposure, both patients with gluten sensitivity and those with active celiac disease demonstrate a greater increase in intestinal permeability than celiacs in disease remission. A higher concentration of IL-10 was measured in the media exposed to control explants compared to celiac disease in remission or gluten sensitivity.
There is debate over the existence of nonceliac gluten sensitivity (NCGS) intestinal and extraintestinal symptoms in response to ingestion of gluten-containing foods by people without celiac disease or wheat allergy. We performed a randomized, double-blind, placebo-controlled, cross-over trial to determine the effects of administration of low doses of gluten to subjects with suspected NCGS.
Background: Nonceliac gluten sensitivity (NCGS), occurring in patients without celiac disease yet whose gastrointestinal symptoms improve on a gluten-free diet (GFD), is largely a self-reported diagnosis and would appear to be very common. The aims of this study were to characterize patients who believe they have NCGS. Materials and Methods: Advertising was directed toward adults who believed they had NCGS and were willing to participate in a clinical trial. Respondents were asked to complete a questionnaire about symptoms, diet, and celiac investigation. Results: Of 248 respondents, 147 completed the survey. Mean age was 43.5 years, and 130 were women. Seventy-two percent did not meet the description of NCGS due to inadequate exclusion of celiac disease (62%), uncontrolled symptoms despite gluten restriction (24%), and not following a GFD (27%), alone or in combination. The GFD was self-initiated in 44% of respondents; in other respondents it was prescribed by alternative health professionals (21%), dietitians (19%), and general practitioners (16%). No celiac investigations had been performed in 15% of respondents. Of 75 respondents who had duodenal biopsies, 29% had no or inadequate gluten intake at the time of endoscopy. Inadequate celiac investigation was common if the GFD was initiated by self (69%), alternative health professionals (70%), general practitioners (46%), or dietitians (43%). In 40 respondents who fulfilled the criteria for NCGS, their knowledge of and adherence to the GFD were excellent, and 65% identified other food intolerances. Conclusions: Just over 1 in 4 respondents self-reporting as NCGS fulfill criteria for its diagnosis. Initiation of a GFD without adequate exclusion of celiac disease is common. In 1 of 4 respondents, symptoms are poorly controlled despite gluten avoidance.
Non-celiac gluten sensitivity is characterized by symptom improvement after gluten withdrawal in absence of celiac disease. The mechanisms of non-celiac gluten sensitivity are unclear, and there are no biomarkers for this disorder. Foods with gluten often contain fructans, a type of fermentable oligo-, di-, monosaccharides and polyols. We aimed to investigate the effect of gluten and fructans separately in individuals with self-reported gluten sensitivity.