Metabolic syndrome in patients with coeliac disease on a gluten-free diet

PNPLA3 rs738409 Polymorphism Predicts Development and Severity of Hepatic Steatosis but Not Metabolic Syndrome in Celiac Disease

Metabolic syndrome (MS) and hepatic steatosis (HS) have been described in patients with celiac disease (CD) after starting a gluten-free diet (GFD), but data on predictive factors for these conditions are scarce. Recently, the patatin-like phospholipase domain-containing protein 3 (PNPLA3) rs738409 has been identified as a key factor for HS development in the general population. The aim of the study was to evaluate the role of PNPLA3 rs738409 in the development of MS and HS in CD patients after starting GFD. Between June 2014 and September 2016, we consecutively enrolled CD patients with HS, while those without steatosis served as a control group. All patients underwent anthropometric and serologic investigations, ultrasonography (US) to assess the degree and severity of HS, and genotyping of the PNPLA3 rs738409 polymorphism. Finally, 370 subjects were enrolled (136 with and 234 without HS). At genotyping assays, the CC genotype was found in 194 subjects (52.4%), the CG genotype in 138 subjects (37.3%), and the GG genotype in 38 subjects (10.2%). At binary logistic regression, only CG and GG alleles were predictive for the development of HS (odds ratio (OR) 1.97; p < 0.01 for CG and OR 6.9; p < 0.001 for GG). Body mass index (BMI) (OR 3.8; p < 0.001) and waist circumference (OR 2.8; p = 0.03) at CD diagnosis were the only independent factors for the development of MS. Intergroup comparisons showed that the severe grade of HS was more frequently observed in GG than in CC carriers (74% vs. 11.3%, p < 0.001, OR 21.8). PNPLA3 CG and GG carriers with CD have a higher susceptibility to hepatic steatosis, but not to metabolic syndrome. Moreover, patients with GG alleles display more severe forms of HS based on ultrasound.

Increased risk of nonalcoholic fatty liver disease in patients with coeliac disease on a gluten-free diet: beyond traditional metabolic factors

BACKGROUND

A gluten-free diet (GFD) is known to be associated with altered macronutrient intake and metabolic syndrome. Nonalcoholic fatty liver disease (NAFLD) is the hepatic hallmark of metabolic syndrome. The risk of NAFLD in patients with coeliac disease (CD) adhering to a GFD remains to be fully investigated; in particular, data from real-life clinical settings are lacking.

AIM

To assess the prevalence and relative risk of NAFLD in CD patients treated with a GFD.

METHODS

Case-control study, with prospective enrolment of CD outpatients following a GFD and controls. Patients were matched for demographic characteristics (age and gender) and metabolic risk factors (overweight, diabetes mellitus, total cholesterol, and triglycerides) using a 1:1 ratio. NAFLD was diagnosed according to the European Association for the Study of the Liver criteria.

RESULTS

202 CD patients and 202 controls were compared. The raw prevalence of NAFLD was 34.7% and 21.8% in the CD and control group, respectively (P = 0.006). Binary logistic regression confirmed an increased risk of NAFLD in the CD group (adjusted odds ratio = 2.90, 95% confidence interval: 1.64-5.15, P < 0.001). Additionally, the relative risk for NAFLD was notably higher in non-overweight CD patients (adjusted odds ratio = 5.71, 95% confidence interval: 2.30-14.19, P < 0.001).

CONCLUSIONS

More than one-third of CD patients adhering to a GFD had concurrent NAFLD, accounting for a three-fold increased risk compared to the general population. Dietary advice provided using a patient-tailored approach should assist CD patients with NAFLD in achieving an appropriate nutritional intake whilst reducing the risk of long-term liver-related events.

Proton pump inhibitors as risk factor for metabolic syndrome and hepatic steatosis in coeliac disease patients on gluten-free diet

BACKGROUND

Recent research has shown that patients with coeliac disease (CD) are at risk of developing metabolic syndrome (MS) and hepatic steatosis (HS) after commencing a gluten-free diet (GFD). This study aimed to evaluate the predictive factors for MS and HS in CD after 1 year of GFD.

METHODS

All consecutive newly diagnosed CD patients were enrolled. We prospectively collected data about BMI; waist circumference; blood pressure; cholesterol; triglycerides, glucose and insulin blood levels; insulin resistance (through the homeostatic model assessment HOMA-IR) and treatment with proton pump inhibitors (PPI). Diagnosis of MS was made in accordance with current guidelines and HS was diagnosed by ultrasonography. The prevalence of MS and HS was re-assessed after 1 year of GFD. A logistic regression analysis was performed to identify risk factors for MS and HS occurrence after 1 year of GFD.

RESULTS

Of 301 patients with newly diagnosed CD, 4.3% met criteria for diagnosis of MS and 25.9% presented with HS at the time of CD diagnosis; 99 subjects (32.8%) had long-term exposure to PPI during the study period. After 1 year, 72 (23.9%) patients had developed MS (4.3 vs 23.9%; p < 0.001, OR 6.9) and 112 (37.2%) had developed HS (25.9 vs 37.2%; p < 0.01, OR 1.69). At multivariate analysis, high BMI at diagnosis (OR 10.8; p < 0.001) and PPI exposure (OR 22.9; p < 0.001) were the only factors associated with the occurrence of MS; HOMA-IR (OR 9.7; p < 0.001) and PPI exposure (OR 9.2; p < 0.001) were the only factors associated with the occurrence of HS.

CONCLUSIONS

PPI exposure adds further risk of occurrence of MS and HS for patients with CD on GFD. The use of PPI in patients with CD on GFD should be limited to strict indications.

Celiac disease and non-celiac gluten or wheat sensitivity and health in later life: A review

Celiac disease (CD) and non-gluten (or wheat) sensitivity (NCGS) are two gluten-related disorders, the treatment of which relies on dietary withdrawal of gluten (absolute and lifelong in the case of CD patients). However, these conditions differ in their pathophysiology and impact on health. CD is an autoimmune disorder of the intestine, and is associated with a wide range of disorders, pre- and post-diagnosis. Its autoimmune and inflammatory nature raises concerns about its potential effects on mortality and morbidity. Here we review the data on the health impact CD or NCGS may have prospectively, and report on the role of a gluten-free diet (GFD) in this respect. Since study designs have been heterogeneous, we focus on studies of treated patients with a biopsy-proven diagnosis of CD, to eliminate possible bias from misdiagnosis. The review revealed a moderately increased mortality risk among CD patients, mainly attributed to cardiovascular disease and malignancy. Other long-term morbidities of CD include autoimmune disorders, nutritional deficiencies, impaired bone health, reproductive abnormalities, and neurologic and neuropsychiatric disorders, which are substantially improved, and some of them even completely treated, after strict adherence to a GFD. For NCGS, the literature is too limited and its long-term complications are unknown.

A New Proposal for the Pathogenic Mechanism of Non-Coeliac/Non-Allergic Gluten/Wheat Sensitivity: Piecing Together the Puzzle of Recent Scientific Evidence

Non-coeliac/non-allergic gluten/wheat sensitivity (NCG/WS) is a gluten-related disorder, the pathogenesis of which remains unclear. Recently, the involvement of an increased intestinal permeability has been recognized in the onset of this clinical condition. However, mechanisms through which it takes place are still unclear. In this review, we attempt to uncover these mechanisms by providing, for the first time, an integrated vision of recent scientific literature, resulting in a new hypothesis about the pathogenic mechanisms involved in NCG/WS. According to this, the root cause of NCG/WS is a particular dysbiotic profile characterized by decreased butyrate-producing-Firmicutes and/or Bifidobacteria, leading to low levels of intestinal butyrate. Beyond a critical threshold of the latter, a chain reaction of events and vicious circles occurs, involving other protagonists such as microbial lipopolysaccharide (LPS), intestinal alkaline phosphatase (IAP) and wheat α-amylase trypsin inhibitors (ATIs). NCG/WS is likely to be a multi-factor-onset disorder, probably transient and preventable, related to quality and balance of the diet, and not to the presence of gluten in itself. If future studies confirm our proposal, this would have important implications both for the definition of the disease, as well as for the prevention and therapeutic-nutritional management of individuals with NCG/WS.

Non-coeliac gluten or wheat sensitivity: emerging disease or misdiagnosis?

Non-coeliac gluten or wheat sensitivity (NCG/WS) is a condition characterised by adverse gastrointestinal and/or extra-intestinal symptoms associated with the ingestion of gluten- or wheat-containing foods, in the absence of coeliac disease or wheat allergy. Up to one in 100 people in Australia may have coeliac disease but many more report adverse gastrointestinal and/or extra-intestinal symptoms after eating wheat products. In the absence of validated biomarkers, a diagnosis of NCG/WS can only be made by a double-blind, placebo-controlled, dietary crossover challenge with gluten, which is difficult to apply in clinical practice. Of people self-reporting gluten or wheat sensitivity, only a small proportion (16%) will have reproducible symptoms after a blinded gluten challenge of gluten versus placebo in a crossover dietary trial and fulfil the current consensus criteria for a diagnosis of NCG/WS. A wide range of symptoms are associated with NCG/WS, including gastrointestinal, neurological, psychiatric, rheumatological and dermatological complaints. The pathogenesis of NCG/WS is not well understood, but the innate immune system has been implicated, and there is overlap with coeliac disease and the functional gastrointestinal disorders (irritable bowel syndrome and functional dyspepsia). Identification of NCG/WS is important as gluten-free diets carry risks, are socially restricting and are costlier than regular diets.

Going Gluten Free: the History and Nutritional Implications of Today's Most Popular Diet

PURPOSE OF REVIEW

The gluten-free diet (GFD) has become one of the most popular diets in modern history. Claims of improved health and increased energy fuel this popularity, though there is little evidence to substantiate these claims. The present review focuses on outlining known gluten-related disorders (GRD), discussing the GFD in the general population, exploring nutritional considerations, and providing advice for physicians in managing these patients.

RECENT FINDINGS

Currently, about a quarter of the population reports keeping a GFD despite GRDs affecting less than half of these individuals. Reduced intake of calcium, B vitamins, and fiber as well as enhanced consumption of fat and simple carbohydrates has consistently been reported and needs to be continually addressed. Although a necessity in proper management of GRDs, unforeseen nutritional complications may develop in patients who are gluten free for which enhanced physician awareness is vital to achieving optimal patient care.

Cardiometabolic risk factors in children with celiac disease on a gluten-free diet

Celiac disease (CD) is an immune-mediated systemic condition evoked by gluten and related prolamines in genetically predisposed subjects. It is characterised by a variable combination of gluten-dependent clinical symptoms, CD-specific antibodies, HLA-DQ2 and HLA-DQ8 haplotypes, and enteropathy. The only therapy of CD consists of a life-long gluten free diet (GFD). Strict GFD adherence results in full clinical, serological and histological remission, avoiding long-term complications in CD patients. However, this diet is not without problems. Gluten free products have high levels of lipids, sugar and salt to improve food palatability and consistency, and subjects with CD show an excessive consumption of hypercaloric and hyperlipidic foods to compensate dietetic restriction. GFD may therefore have a negative impact on cardiometabolic risk factors such as obesity, serum lipid levels, insulin resistance, metabolic syndrome, and atherosclerosis. In adults, some studies have suggested that GFD have a beneficial effect on cardiovascular profile, whereas others have shown an atherogenic effect of GFD. In children, very few studies are available on the issue. Thus, the aim of the present narrative review was to analyze the current clinical evidence on the impact of GFD on cardiometabolic risk factors in children with CD.

Gluten-Free Diet Indications, Safety, Quality, Labels, and Challenges

A gluten-free diet (GFD) is the safest treatment modality in patient with coeliac disease (CD) and other gluten-related disorders. Contamination and diet compliance are important factors behind persistent symptoms in patients with gluten related-disorders, in particular CD. How much gluten can be tolerated, how safe are the current gluten-free (GF) products, what are the benefits and side effects of GFD? Recent studies published in Nutrients on gluten-free products' quality, availability, safety, as well as challenges related to a GFD are discussed.

Lack of immunogenicity of hydrolysed wheat flour in patients with coeliac disease after a short-term oral challenge

BACKGROUND

A gluten-free diet is currently the only reliable therapeutic strategy that is approved for coeliac disease (CD). For many patients, however, compliance remains inadequate.

AIM

To investigate the immunogenicity of wheat flour that was pre-treated with selected lactobacilli and fungal proteases (hydrolysed wheat gluten) in coeliac patients.

METHODS

The immunogenicity of hydrolysed wheat gluten was evaluated both in vitro in intestinal T cell lines (TCLs) and in vivo in treated CD patients after a short-term gluten challenge. Twenty treated CD patients were enrolled and equally randomised into two groups. The patients ate bread that was prepared with hydrolysed wheat flour or natural wheat flour (10 g of gluten/d for 3 days). The interferon (INF)-γ responses to natural gliadin and a 33-mer peptide were assessed by the enzyme-linked immunospot (ELISPOT) assay on peripheral blood mononuclear cells (PBMCs) both before and 6 days after the start of the challenge.

RESULTS

Hydrolysed wheat was not able to activate the TCLs from the coeliac intestinal mucosa. Consistent with the in vitro results, no significant increase in INF-γ secretion was observed in patients who consumed hydrolysed wheat flour. Conversely, the consumption of natural wheat gluten mobilised INF-γ secreting cells in the blood (P<.05).

CONCLUSIONS

We confirm that fermentation of wheat flour with sourdough lactobacilli and fungal proteases is capable of abolishing the T cell immunogenicity of gluten in coeliac patients. Our data also validate the short-term oral challenge as a useful tool for testing the efficacy of novel therapeutic approaches.

Serum Concentrations of Insulin, Ghrelin, Adiponectin, Leptin, Leptin Receptor and Lipocalin-2 in Children with Celiac Disease Who Do and Do Not Adhere to a Gluten-Free Diet

Background/Aims

The roles of the many bioactive peptides in the pathogenesis of celiac disease remain unclear. To evaluate the serum concentrations of insulin, ghrelin, adiponectin, leptin, leptin receptor, and lipocalin-2 in children with celiac disease who do and do not adhere to a gluten-free diet (GFD, intermittent adherence).

Methods

Prepubertal, pubertal, and adolescent celiac children were included in this study (74 girls and 53 boys on a GFD and 80 girls and 40 boys off of a GFD).

Results

Insulin levels in prepubertal (9.01±4.43 μIU/mL), pubertal (10.3±3.62 μIU/mL), and adolescent (10.8±4.73 μIU/mL) girls were higher than those in boys (5.88±2.02, 8.81±2.88, and 8.81±2.26 μIU/mL, respectively) and were neither age-dependent nor influenced by a GFD. Prepubertal children off of a GFD exhibited higher ghrelin levels than prepubertal children on a GFD. Adiponectin levels were not age-, sex- nor GFD-dependent. Adherence to a GFD had no effect on the expression of leptin, leptin receptor, and lipocalin-2.

Conclusions

Adherence to a GFD had no influence on the adiponectin, leptin, leptin receptor, and lipocalin-2 concentrations in celiac children, but a GFD decreased highly elevated ghrelin levels in prepubertal children. Further studies are required to determine whether increased insulin concentrations in girls with celiac disease is suggestive of an increased risk for hyperinsulinemia.

Markers of inflammation and cardiovascular disease in recently diagnosed celiac disease patients

AIM

To evaluate novel risk factors and biomarkers of cardiovascular disease in celiac disease (CD) patients compared with healthy controls.

METHODS

Twenty adult patients with recent diagnosis of CD and 20 sex, age and body mass index-matched healthy controls were recruited during a period of 12 mo. Indicators of carbohydrate metabolism, hematological parameters and high sensitive C reactive protein were determined. Moreover, lipoprotein metabolism was also explored through evaluation of the lipid profile and the activity of cholesteryl ester transfer protein and lipoprotein associated phospholipase A2, which is also considered a specific marker of vascular inflammation. The protocol was approved by the Ethic Committee from School of Pharmacy and Biochemistry, University of Buenos Aires and from Buenos Aires Italian Hospital, Buenos Aires, Argentina.

RESULTS

Regarding the indicators of insulin resistance, CD patients showed higher plasma insulin levels [7.2 (5.0-11.3) mU/L vs 4.6 (2.6-6.7) mU/L, P < 0.05], increased Homeostasis Model Assessment-Insulin Resistance [1.45 (1.04-2.24) vs 1.00 (0.51-1.45), P < 0.05] and lower Quantitative Sensitive Check index [0.33 (0.28-0.40) vs 0.42 (0.34-0.65), P < 0.05] indexes. Folic acid concentration [5.4 (4.4-7.9) ng/mL vs 12.2 (8.0-14.2) ng/mL, P < 0.01] resulted to be lower and High-sensitivity C reactive protein levels higher (4.21 ± 6.47 mg/L vs 0.98 ± 1.13 mg/L, P < 0.01) in the patient group. With respect to the lipoprotein profile, CD patients showed lower high density lipoprotein-cholesterol (HDL-C) (45 ± 15 mg/dL vs 57 ± 17 mg/dL, P < 0.05) and apo A-I (130 ± 31 mg/dL vs 155 ± 29 mg/dL, P < 0.05) levels, as well as higher total cholesterol/HDL-C [4.19 (3.11-5.00) vs 3.52 (2.84-4.08), P < 0.05] and apo B/apo A-I (0.75 ± 0.25 vs 0.55 ± 0.16, P < 0.05) ratios in comparison with control subjects. No statistically significant differences were detected in lipoprotein-associated lipid transfer protein and enzymes.

CONCLUSION

The presence and interaction of the detected alterations in patients with CD, would constitute a risk factor for the development of atherosclerotic cardiovascular disease.

How to improve the gluten-free diet: The state of the art from a food science perspective

The celiac disease is the most common food intolerance and its prevalence is increasing. Consequently, use of gluten-free diet has expanded, notwithstanding consumption as therapy for other gluten-related disorders or by wellbeing people without any medical prescription. Even the therapeutic efficiency has undoubtedly proven, several drawbacks mainly regarding the compliance, nutritional deficits and related diseases, and the alteration of the intestinal microbiota have described in the literature. Food science has been considered as one of the primary area of intervention to limit or eliminate such drawbacks. Efforts have approached shelf life, rheology and palatability aspects but more recently have mainly focused to improve the nutritional features of the gluten-free diet, and to propose dietary alternatives. The sourdough fermentation has shown the most promising results, also including a biotechnology strategy that has allowed the complete degradation of gluten prior to consumption.

Less Hidden Celiac Disease But Increased Gluten Avoidance Without a Diagnosis in the United States: Findings From the National Health and Nutrition Examination Surveys From 2009 to 2014

OBJECTIVE

To investigate the trends in the prevalence of diagnosed celiac disease (CD), undiagnosed CD, and people without celiac disease avoiding gluten (PWAG) in the civilian noninstitutionalized US population from 2009 to 2014.

PATIENTS AND METHODS

We studied the occurrence of CD and PWAG in the 2009 to 2014 National Health and Nutrition Examination Surveys. The serum of all participants aged 6 years or older from the National Health and Nutrition Examination Surveys from 2009 to 2014 was tested for CD serology at Mayo Clinic. Participants were interviewed for a diagnosis of CD and the use of a gluten-free diet (GFD). The design effects of the survey and sample weights were incorporated in all statistical analyses.

RESULTS

In the US general population, the prevalence of CD did not change significantly from 0.7% (95% CI, 0.6%-0.8%) in 2009 to 2010 to 0.8% (95% CI, 0.4%-1.2%) in 2011 to 2012 to 0.7% (95% CI, 0.3%-1.0%) in 2013 to 2014. However, the prevalence of undiagnosed CD decreased from 0.6% in 2009 to 2010 to 0.3% in 2013 to 2014. In contrast, the prevalence of PWAG increased significantly from 0.5% (95% CI, 0.2%-0.9%) in 2009 to 2010 to 1.0% (95% CI, 0.6%-1.4%) in 2011 to 2012 to 1.7% (95% CI, 1.1%-2.4%) in 2013 to 2014 (P=.005 for trend).

CONCLUSION

Although the overall prevalence of CD remained stable from 2009 to 2014, the proportion of individuals with CD that is hidden considerably decreased. Moreover, the proportion of individuals without CD but following a GFD increased markedly from 2009 to 2014. Long-term health consequences of a GFD warrant further investigation.

Transition from childhood to adulthood in coeliac disease: the Prague consensus report

The process of transition from childhood to adulthood is characterised by physical, mental and psychosocial development. Data on the transition and transfer of care in adolescents/young adults with coeliac disease (CD) are scarce. In this paper, 17 physicians from 10 countries (Sweden, Italy, the USA, Germany, Norway, the Netherlands, Australia, Britain, Israel and Denmark) and two representatives from patient organisations (Association of European Coeliac Societies and the US Celiac Disease Foundation) examined the literature on transition from childhood to adulthood in CD. Medline (Ovid) and EMBASE were searched between 1900 and September 2015. Evidence in retrieved reports was evaluated using the Grading of Recommendation Assessment, Development and Evaluation method. The current consensus report aims to help healthcare personnel manage CD in the adolescent and young adult and provide optimal care and transition into adult healthcare for patients with this disease. In adolescence, patients with CD should gradually assume exclusive responsibility for their care, although parental support is still important. Dietary adherence and consequences of non-adherence should be discussed during transition. In most adolescents and young adults, routine small intestinal biopsy is not needed to reconfirm a childhood diagnosis of CD based on European Society for Pediatric Gastroenterology, Hepatology and Nutrition (ESPGHAN) or North American Society for Pediatric Gastroenterology, Hepatology and Nutrition (NASPGHAN) criteria, but a biopsy may be considered where paediatric diagnostic criteria have not been fulfilled, such as, in a patient without biopsy at diagnosis, additional serology (endomysium antibody) has not been performed to confirm 10-fold positivity of tissue transglutaminase antibodies or when a no biopsy strategy has been adopted in an asymptomatic child.

Gluten-free diet does not influence the occurrence and the Th1/Th17-Th2 nature of immune-mediated diseases in patients with coeliac disease

INTRODUCTION

Coeliac disease (CD) is the most common Th1-mediated enteropathy, frequently associated with other immune-mediated disorders (IMD).

AIMS

To evaluate: (1) the prevalence of IMD at the time of and after CD diagnosis; (2) a possible change in immune response to gluten free diet (GFD); (3) the potential role of GFD in reducing and/or preventing IMD in CD.

METHODS

Prospective study including all consecutive adult CD patients who underwent investigations for Th1-Th17/Th2-IMD at the time of CD diagnosis and after a 5-year follow-up period.

RESULTS

1255 CD were enrolled. Of these, 257 patients (20.5%) showed IMD at the time of CD diagnosis, with 58.4% presenting a Th1/Th17-IMD. After a 5-year follow-up period, 682 patients (54.3%) showed new IMD despite GFD. Of these, 57.3% presented a Th1/Th17-IMD and 42.7% a Th2-IMD (p=0.8). When compared the prevalence of each type of IMD before and after CD diagnosis, we did not identify any significant "switch" from Th1/Th17- to Th2-IMD or vice versa. The number of patients with Th1/Th17- and/or Th2-IMD increased during the GFD period (20.5% vs 54.3%; p<0.01; OR 1.9).

CONCLUSIONS

The prevalence of IMD at the time of CD diagnosis is high and it seems to increase in the follow-up period despite GFD.

Practical insights into gluten-free diets

Coeliac disease is a global disease, and the only currently available treatment is a gluten-free diet (GFD). Although conceptually simple, the diet changes are substantial and have a profound effect on a patient's life. Untreated coeliac disease is associated with complications, including excess mortality, most of which can be avoided with a strict GFD. However, there are many barriers, including availability, cost and safety of gluten-free foods, and gluten cross-contamination. The GFD can be restrictive in social situations, leading to poor quality of life and, ultimately, nonadherence. As the number of patients with coeliac disease increases worldwide, clinicians need to be aware of the challenges patients face. Heightened awareness by physicians, dietitians and other providers can help maximize successful treatment, improve outcomes, and reduce health-care costs and disease burden. Routine follow-up is necessary to reinforce the need for a GFD, provide social and emotional support, and achieve mucosal healing, leading to reduced risk of complications. Unfortunately, there is wide variation in follow-up practices. The objective of this Review is to increase awareness of the challenges, management and follow-up of patients with coeliac disease to help them achieve GFD adherence and prevent complications whilst preserving their quality of life.

The Gluten-Free Diet in the 3rd Millennium: Rules, Risks and Opportunities

The gluten-free diet has long been considered the standard treatment for celiac disease. However, a significant number of patients continue to experience persistent symptoms despite following a gluten-free diet. Inadvertent gluten ingestion, fermentable carbohydrates, cross-contamination, and social or financial burdens present obstacles to maintaining a gluten-free diet. Proper diet education and follow-up by an expert Registered Dietitian (RD) is essential to ensure adequate nutrition on the gluten-free diet. Patients may experience unintended weight gain or elevated cholesterol levels after initiating the gluten-free diet due to adequate absorption and healing of the intestines. This review deals with the evolving gluten-free diet, optimal recommendations while considering the overall health of patients, and multi-factorial aspects of the permanent lifestyle change.

Systematic review: noncoeliac gluten sensitivity

BACKGROUND

Noncoeliac gluten sensitivity (NCGS) is a controversial emerging disorder. Despite reported symptoms related to the ingestion of gluten, NCGS remains a diagnosis based on the exclusion of coeliac disease, given the absence of reliable biomarkers.

AIM

To evaluate the prevalence, diagnostic exclusion of coeliac disease and the efficacy of a gluten-free diet (GFD) for NCGS patients.

METHODS

A PubMed search was performed up to December 2014. According to consensus diagnostic criteria, NCGS was defined as self-reported gluten intolerance, negative coeliac serology and absence of villous atrophy. Studies evaluating the impact of a GFD on patients with irritable bowel syndrome (IBS) were also included.

RESULTS

Prevalence rates of NCGS (0.5-13%) differed widely. Seventeen studies, including 1561 patients (26 children), met the inclusion criteria for NCGS. HLA haplotypes could not be linked to histology [normal or lymphocytic enteritis (LE)] in 1123 NCGS patients. HLADQ2/DQ8 haplotypes were present in 44% of NCGS patients. After advanced diagnostic techniques in 189 NCGS patients combining LE and HLADQ2/DQ8 haplotypes, 39 (20%) were reclassified as coeliac disease. There was a higher than expected family history of coeliac disease and autoimmune disorders in NCGS patients. A GFD resulted in variable results for variable, but significantly improved stool frequency in HLADQ2 positive diarrhoea-predominant IBS patients.

CONCLUSIONS

Prevalence rates for NCGS are extremely variable. A subset of NCGS patients might belong in the so-called 'coeliac-lite' disease. The benefit of a GFD for NCGS patients is currently controversial. HLADQ2 positive diarrhoea-type IBS patients might gain symptom improvement from a GFD.