Non-celiac gluten sensitivity: questions still to be answered despite increasing awareness.

Abstract

"Recently, the increasing number of patients worldwide who are sensitive to dietary gluten without evidence of celiac disease or wheat allergy has contributed to the identification of a new gluten-related syndrome defined as non-celiac gluten sensitivity. Our knowledge regarding this syndrome is still lacking, and many aspects of this syndrome remain unknown. Its pathogenesis is heterogeneous, with a recognized pivotal role for innate immunity; many other factors also contribute, including low-grade intestinal inflammation, increased intestinal barrier function and changes in the intestinal microbiota. Gluten and other wheat proteins, such as amylase trypsin inhibitors, are the primary triggers of this syndrome, but it has also been hypothesized that a diet rich in fermentable monosaccharides and polyols may elicit its functional gastrointestinal symptoms. The epidemiology of this condition is far from established; its prevalence in the general population is highly variable, ranging from 0.63% to 6%. From a clinical point of view, non-celiac gluten sensitivity is characterized by a wide array of gastrointestinal and extraintestinal symptoms that occur shortly after the ingestion of gluten and improve or disappear when glutenis withdrawn from the diet. These symptoms recur when gluten is reintroduced. Because diagnostic biomarkers have not yet been identified, a double-blind placebo-controlled gluten challenge is currently the diagnostic method with the highest accuracy. Future research is needed to generate more knowledge regarding non-celiac glutensensitivity, a condition that has global acceptance but has only a few certainties and many unresolved issues."

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Non-celiac gluten sensitivity: the new frontier of gluten related disorders.

Abstract

"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."

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Does gluten cause gastrointestinal symptoms in subjects without coeliac disease?

Abstract

"AIM:

To determine the evidence for the effect of gluten ingestion on gastrointestinal symptoms, intestinal permeability and other indices of small intestinal injury in non-coeliac, gluten intolerant individuals.

METHODS:

A literature review was performed searching for interventional studies that addressed the issue.

RESULTS:

One unblinded study that identified symptomatic response to gluten did not effectively exclude patients with coeliac disease, since many had intraepithelial lymphocytosis. A double-blinded, randomised, placebo-controlled rechallenge trial was recently reported in patients in whom coeliac disease had been excluded by either normal duodenal histology on a gluten containing diet, or absence of the HLA DQ2 or DQ8 haplotype (56%). Participants were randomly assigned to receive either 16 g/day carbohydrate-free gluten or placebo for six weeks. Participants were enrolled if they had gastrointestinal symptoms that had improved on a GFD and had been on a gluten free diet for at least 6 weeks prior to enrollment. 19 received gluten and 15 received placebo. Change between baseline and final weeks were greater for patients receiving gluten in overall symptom severity compared with those receiving placebo (p=0.047). and were worse with gluten within one week for pain (p=0.016), bloating (p=0.031), satisfaction with stool consistency (p=0.024), and tiredness (p=0.001). Mechanisms for symptom induction were not identified.

CONCLUSIONS:

Non-coeliac gluten intolerance does exist. Future studies need to identify issues of the dose of gluten needed and mechanisms of action."

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Non-celiac wheat sensitivity: separating the wheat from the chat!

Abstract

"Historically, it has been reported that patients with undetected celiac disease (CD) may present with irritable bowel syndrome (IBS) type symptoms. This has led to the recommendation by the American College of Gastroenterology Task force that patients presenting with diarrhea predominant IBS type symptoms should be serologically tested for CD. Concurrently speculative media data suggest that the US general public have increased their uptake of a gluten-free diet (GFD) far in excess of the known prevalence of CD. This may suggest that individuals with gastrointestinal symptoms are deriving benefit from a GFD even if they do not have CD. This has led to the scientific community considering the evidence for an emerging concept ofnon-celiac wheat sensitivity. There is a significant disparity in our views about what this phenomenon may be. There is also confusion about the nomenclature for this entity and indeed whether patients are suffering due to symptoms related to gluten or perhaps other components of wheat, for example fructans. In this month's edition of the American Journal of Gastroenterology, we see evidence to support the clinical concept of wheat sensitivity or intolerance. Irrespective of the nomenclature Carroccio provides a clinically applicable approach that may be adopted internationally by clinicians. This offers a new option in our armamentarium when seeing patients with IBS type symptoms."

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