Should We All Go Gluten-Free?
http://www.medscape.com/viewarticle/857971_4
Differentiating between celiac disease, NCGS, and other wheat-related disorders can be challenging, but it is important for appropriate management. As stated in a recent editorial, it is counterproductive to debate whether NCGS is "real"; the patients are real and are seeking care.
The current clinical approach involves ruling out celiac disease and wheat allergy, testing for additional food intolerances or gastrointestinal conditions, and providing the latest data on the benefit/unintended consequences of gluten avoidance and these evolving entities. It is also important to inform patients and their families about what is not known. It may also be effective to individualize the recommended dietary strategy by eliminating certain components of the FODMAP class, wheat products, and/or gluten sequentially.
Because there is no specific biomarker for NCGS, the diagnosis is "confirmed" by dietary elimination, followed by double-blind, placebo-controlled gluten-based re-challenges. This is a cumbersome, time-consuming, and difficult-to-access clinical approach. Even with this information at hand, the diagnosis of NCGS may remain unclear, raising the question of whether the salutary effects of gluten withdrawal are specifically attributed to the gluten-protein per se or to nongluten components such as fermentable carbohydrates and amylase-trypsin inhibitors.
Khabbani and colleagues reviewed records from 238 patients who presented for the evaluation of symptoms responsive to gluten restriction without prior exclusion of celiac disease. Of these study subjects, 42% had celiac disease and 52% had NCGS; the remainder had an indeterminate diagnosis. The majority (67%) of subjects with celiac disease presented with symptoms of malabsorption, compared with 25% of the NCGS subjects. In addition, those with celiac disease were significantly more likely to have a family history of celiac disease, personal history of autoimmune diseases, or nutrient deficiencies.
On the basis of these findings, the authors proposed a diagnostic algorithm to differentiate celiac disease from NCGS. They state that subjects with negative celiac serologies (IgA tTG or IgA/IgG DGP) ingesting a gluten-containing diet are unlikely to have celiac disease. Those with negative serology who also lack clinical evidence of malabsorption and risk factors for celiac disease are highly likely to have NCGS and may not require further testing. Those with equivocal serology should undergo HLA typing to determine the need for biopsy.
Guandalini and colleagues proposed assessment of the levels of gamma delta T-cell receptors in intraepithelial lymphocytes (which are specific for celiac disease) or detection of IgA anti-tissue transglutaminase antibody deposits in intestinal mucosa in order to more clearly exclude celiac disease in problematic cases.
Remaining Questions:
As stated by Fasano and colleagues, a better understanding of the clinical presentation of NCGS is needed, as well as its pathogenesis, epidemiology, management, and role in conditions such as IBS, chronic fatigue, and autoimmunity. There also must be agreement on the nomenclature and definition of gluten/wheat-related disorders based on proper peer-reviewed scientific information.
It is hoped that in the future, the terms NCGS, NCWS, and wheat intolerance syndrome will be replaced by well-defined nosology, that the phenotypes and mechanisms of syndromes responsive to gluten withdrawal will be better defined, and that there will be biomarkers and definitive therapy for distinct entities.
http://www.medscape.com/viewarticle/857971_4
Differentiating between celiac disease, NCGS, and other wheat-related disorders can be challenging, but it is important for appropriate management. As stated in a recent editorial, it is counterproductive to debate whether NCGS is "real"; the patients are real and are seeking care.
The current clinical approach involves ruling out celiac disease and wheat allergy, testing for additional food intolerances or gastrointestinal conditions, and providing the latest data on the benefit/unintended consequences of gluten avoidance and these evolving entities. It is also important to inform patients and their families about what is not known. It may also be effective to individualize the recommended dietary strategy by eliminating certain components of the FODMAP class, wheat products, and/or gluten sequentially.
Because there is no specific biomarker for NCGS, the diagnosis is "confirmed" by dietary elimination, followed by double-blind, placebo-controlled gluten-based re-challenges. This is a cumbersome, time-consuming, and difficult-to-access clinical approach. Even with this information at hand, the diagnosis of NCGS may remain unclear, raising the question of whether the salutary effects of gluten withdrawal are specifically attributed to the gluten-protein per se or to nongluten components such as fermentable carbohydrates and amylase-trypsin inhibitors.
Khabbani and colleagues reviewed records from 238 patients who presented for the evaluation of symptoms responsive to gluten restriction without prior exclusion of celiac disease. Of these study subjects, 42% had celiac disease and 52% had NCGS; the remainder had an indeterminate diagnosis. The majority (67%) of subjects with celiac disease presented with symptoms of malabsorption, compared with 25% of the NCGS subjects. In addition, those with celiac disease were significantly more likely to have a family history of celiac disease, personal history of autoimmune diseases, or nutrient deficiencies.
On the basis of these findings, the authors proposed a diagnostic algorithm to differentiate celiac disease from NCGS. They state that subjects with negative celiac serologies (IgA tTG or IgA/IgG DGP) ingesting a gluten-containing diet are unlikely to have celiac disease. Those with negative serology who also lack clinical evidence of malabsorption and risk factors for celiac disease are highly likely to have NCGS and may not require further testing. Those with equivocal serology should undergo HLA typing to determine the need for biopsy.
Guandalini and colleagues proposed assessment of the levels of gamma delta T-cell receptors in intraepithelial lymphocytes (which are specific for celiac disease) or detection of IgA anti-tissue transglutaminase antibody deposits in intestinal mucosa in order to more clearly exclude celiac disease in problematic cases.
Remaining Questions:
As stated by Fasano and colleagues, a better understanding of the clinical presentation of NCGS is needed, as well as its pathogenesis, epidemiology, management, and role in conditions such as IBS, chronic fatigue, and autoimmunity. There also must be agreement on the nomenclature and definition of gluten/wheat-related disorders based on proper peer-reviewed scientific information.
It is hoped that in the future, the terms NCGS, NCWS, and wheat intolerance syndrome will be replaced by well-defined nosology, that the phenotypes and mechanisms of syndromes responsive to gluten withdrawal will be better defined, and that there will be biomarkers and definitive therapy for distinct entities.
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