Celiac Disease and Gluten-Free Oats: A Canadian Position Based on a Literature Review

Three Decades of Rust Surveys in the United States Reveal Drastic Virulence Changes in Oat Crown Rust

To better understand how the pathogenicity of the oat crown rust pathogen Puccinia coronata f. sp. avenae (Pca) has changed in the United States, 30 years of United States Department of Agriculture (USDA) survey isolates (n = 5,456) tested on 30 to 40 differential lines were analyzed for overall and Pc-resistance-gene-specific virulence trends and correlations. Pca is incredibly pathologically diverse, with 88% of races represented by a single isolate. There are a slightly higher proportion of unique races from the Northern region of the United States, and for one fourth of the years, Northern region isolates were significantly more virulent than Southern isolates, which supports the idea that sexual recombination in this region is mediated by the alternate host as a major factor in creating new races. However, there is also support for regular isolate movement between North and South regions as isolates in the United States are steadily accumulating virulences at a rate of 0.35 virulences per year. Virulence significantly increased for 23 and decreased for four of the 40 differential lines. In the past few years, virulence has reached 90% or greater for 16 differential lines. There were also strong correlations in virulence for certain Pc genes that are likely identical, allelic, or target the same or closely linked pathogen effectors (e.g., Pc39, Pc55, and Pc71), and the results were largely in concordance with recent genome-wide association study (GWAS) effector studies using USDA isolate subsets. Understanding changes in Pca pathogenicity is essential for the responsible deployment and management of Pc resistance genes for sustainable and profitable oat production.

Gluten-free diet for pediatric patients with coeliac disease: A position paper from the ESPGHAN gastroenterology committee, special interest group in coeliac disease

BACKGROUND AND OBJECTIVE

Coeliac disease is a chronic, immune-mediated disorder for which the only treatment consists of lifelong strict adherence to gluten-free diet (GFD). However, there is a lack of evidence-based guidelines on the GFD dietary management of coeliac disease. This position paper, led by the Special Interest Group in coeliac disease of the European Society of Pediatric, Gastroenterology Hepatology, and Nutrition, supported by the Nutrition Committee and the Allied Health Professionals Committee, aims to present evidence-based recommendations on the GFD as well as how to support dietary adherence.

METHODS

A wide literature search was performed using the MeSH Terms: "diet, gluten free," "gluten-free diet," "diets, gluten-free," "gluten free diet," and "coeliac disease" in Pubmed until November 8th, 2022.

RESULTS

The manuscript provides an overview of the definition of the GFD, regulations as basis to define the term "gluten-free," which foods are naturally gluten-free and gluten-containing. Moreover, it provides recommendations and educational tips and infographics on suitable food substitutes, the importance of reading food labels, risk of gluten cross-contact at home and in public settings, nutritional considerations as well as factors associated to dietary adherence based on available evidence, or otherwise clinical expertise.

CONCLUSIONS

This position paper provides guidance and recommendations to support children with coeliac disease to safely adhere to a GFD.

Dietary trends and obesity in Saudi Arabia

Introduction

Dietary habits in Saudi Arabia have been shifting toward the Western diet, which is high in fat, salt, and sugar, leading to a high obesity rate. Different dietary strategies such as the Ketogenic Diet (KD), Intermittent Fasting (IF), Gluten Free Diet (GFD), and Calorie Restriction Diet (CRD) have shown an influential role in weight loss. This study aimed to compare trending diets and correlate different types of diet with obesity and lifestyle among adults in Saudi Arabia.

Methods

A cross-sectional study was performed on Saudis and non-Saudis over 18 years old. We used convenience sampling, an online questionnaire distributed via social media channels, including WhatsApp, LinkedIn, and Twitter. SPSS 28 software was applied for data analysis. The chi-square test was used to determine associations between different variables. Statistical significance was considered at a value of p less than 0.05.

Results

Most participants were females residing in the Eastern and Central regions of Saudi Arabia. Although most do not follow any dietary plan, they exhibited acceptable exercise and lifestyle. The minority of the study population followed different types of diet plans, such as KD, IF, and GFD. The purpose of most of the participants who have used these strategies was for weight loss but failed to sustain the dietary plan for more than 1 month.

Conclusion

Obesity remains a challenging issue in Saudi Arabia. Adherence to dietary regimes could help in controlling obesity. Increasing the awareness of the benefits of each dietary plan for health, choosing the appropriate one, and sustaining a balanced nutrition pattern.

Coeliac disease

Coeliac disease is an autoimmune disorder that primarily affects the small intestine, and is caused by the ingestion of gluten in genetically susceptible individuals. Prevalence in the general population ranges from 0·5% to 2%, with an average of about 1%. The development of the coeliac enteropathy depends on a complex immune response to gluten proteins, including both adaptive and innate mechanisms. Clinical presentation of coeliac disease is highly variable and includes classical and non-classical gastrointestinal symptoms, extraintestinal manifestations, and subclinical cases. The disease is associated with a risk of complications, such as osteoporosis and intestinal lymphoma. Diagnosis of coeliac disease requires a positive serology (IgA anti-transglutaminase 2 and anti-endomysial antibodies) and villous atrophy on small-intestinal biopsy. Treatment involves a gluten-free diet; however, owing to the high psychosocial burden of such a diet, research into alternative pharmacological treatments is currently very active.

Challenges in Gluten Analysis: A Comparison of Four Commercial Sandwich ELISA Kits

Gluten is composed of prolamin and glutelin proteins from several related grains. Because these proteins are not present in identical ratios in the various grains and because they have some differences in sequence, the ability to accurately quantify the overall amount of gluten in various food matrices to support gluten-free labeling is difficult. Four sandwich ELISAs (the R-Biopharm AG R5 RIDASCREEN^®, the Neogen Veratox^® R5, the Romer Labs AgraQuant^® G12, and the Morinaga Wheat kits) were evaluated for their performance to quantify gluten concentrations in various foods and ingredients. The Morinaga and AgraQuant^® G12 tests yielded results comparable to the two R5 kits for most, but not for certain, foods. The results obtained with the Morinaga kit were lower when compared to the other kits for analyzing powders of buckwheat and several grass-based products. All four kits were capable of detecting multiple gluten-containing grain sources including wheat, rye, barley, semolina, triticale, spelt, emmer, einkorn, Kamut™, and club wheat. Users of the ELISA kits should verify the performance in their hands, with matrices that are typical for their specific uses. The variation in results for some food matrices between test methods could result in trade disputes or regulatory disagreements.

The Role of Pseudocereals in Celiac Disease: Reducing Nutritional Deficiencies to Improve Well-Being and Health

Celiac disease or gluten-dependent enteropathy is a chronic autoimmune pathology triggered by dietary gluten in genetic predisposed individuals, mediated by transglutaminase 2 IgA autoantibodies and associated with a deteriorating immune and inflammatory response. This leads to intestinal villous atrophy, impairing the intestinal mucosa structure and function of secretion, digestion, and absorption. The result is macro- and micronutrient deficiency, including fat soluble vitamins and minerals, and a consequent nutritional status depletion. A lifelong gluten-free diet is the only available treatment for celiac patients in order to assure normal intestinal mucosa and remission of gastrointestinal symptoms. However, a gluten-free diet can itself cause other nutritional deficiencies due to its restrictive nature regarding gluten-containing cereals. A group of gluten-free cereals, known as pseudocereals, is increasingly recognized as valuable options for gluten-free diets due to their high nutritional value. Amaranth, quinoa, millet, and buckwheat are examples of gluten-free nutrient-dense grains that can be used as alternatives to the conventional gluten-containing grains and improve the variety and nutritional quality of the celiac diet. Current work reviews the nutritional pitfalls of a gluten-free diet and analyses how pseudocereals can contribute to revert those deficiencies and optimize the nutritional value of this mandatory diet for the celiac population.

Investigation of Protein and Epitope Characteristics of Oats and Its Implications for Celiac Disease

The use of pure oats (oats cultivated with special care to avoid gluten contamination from wheat, rye, and barley) in the gluten-free diet (GFD) represents important nutritional benefits for the celiac consumer. However, emerging evidence suggests that some oat cultivars may contain wheat gliadin analog polypeptides. Consequently, it is necessary to screen oats in terms of protein and epitope composition to be able to select safe varieties for gluten-free applications. The overall aim of our study is to investigate the variability of oat protein composition directly related to health-related and techno-functional properties. Elements of an oat sample population representing 162 cultivated varieties from 20 countries and the protein composition of resulting samples have been characterized. Size distribution of the total protein extracts has been analyzed by size exclusion-high performance liquid chromatography (SE-HPLC) while the 70% ethanol-extracted proteins were analyzed by RP-HPLC. Protein extracts separated into three main groups of fractions on the SE-HPLC column: polymeric proteins, avenins (both containing three subgroups based on their size), and soluble proteins, representing respectively 68.79–86.60, 8.86–27.72, and 2.89–11.85% of the total protein content. The ratio of polymeric to monomeric proteins varied between 1.37 and 3.73. Seventy-six reversed phase-HPLC-separated peaks have been differentiated from the ethanol extractable proteins of the entire population. Their distribution among the cultivars varied significantly, 6–23 peaks per cultivar. The number of appearances of peaks also showed large variation: one peak has been found in 107 samples, while 15 peaks have been identified, which appeared in less than five cultivars. An estimation method for ranking the avenin-epitope content of the samples has been developed by using MS spectrometric data of collected RP-HPLC peaks and bioinformatics methods. Using ELISA methodology with the R5 antibody, a high number of the investigated samples were found to be contaminated with wheat, barley, or rye.

Evaluation of the discriminatory potential of antibodies created from synthetic peptides derived from wheat, barley, rye and oat gluten

Celiac disease (CD) is triggered by ingestion of gluten-containing cereals such as wheat, barley, rye and in some cases oat. The only way for affected individuals to avoid symptoms of this condition is to adopt a gluten-free diet. Thus, gluten-free foodstuffs need to be monitored in order to ensure their innocuity. For this purpose, commercial immunoassays based on recognition of defined linear gluten sequences are currently used. These immunoassays are designed to detect or quantify total gluten regardless of the cereal, and often result in over or underestimation of the exact gluten content. In addition, Canadian regulations require a declaration of the source of gluten on the label of prepackaged foods, which cannot be done due to the limitations of existing methods. In this study, the development of new antibodies targeting discrimination of gluten sources was conducted using synthetic peptides as immunization strategy. Fourteen synthetic peptides selected from unique linear amino acid sequences of gluten were bioconjugated to Concholepas concholepas hemocyanin (CCH) as protein carrier, to elicit antibodies in rabbit. The resulting polyclonal antibodies (pAbs) successfully discriminated wheat, barley and oat prolamins during indirect ELISA assessments. pAbs raised against rye synthetic peptides cross-reacted evenly with wheat and rye prolamins but could still be useful to successfully discriminate gluten sources in combination with the other pAbs. Discrimination of gluten sources can be further refined and enhanced by raising monoclonal antibodies using a similar immunization strategy. A methodology capable of discriminating gluten sources, such as the one proposed in this study, could facilitate compliance with Canadian regulations on this matter. This type of discrimination could also complement current immunoassays by settling the issue of over and underestimation of gluten content, thus improving the safety of food intended to CD and wheat-allergic patients.

Prevalence of Celiac Disease in Patients With Turner Syndrome: Systematic Review and Meta-Analysis

Introduction: Celiac disease (CD) is a multifactorial autoimmune disorder, and studies have reported that patients with Turner syndrome (TS) are at risk for CD. This systematic review and meta-analysis aimed to quantify the weighted prevalence of CD among patients with TS and determine the weighted strength of association between TS and CD.

Methods: Studies published between January 1991 and December 2019 were retrieved from four electronic databases: PubMed, Scopus, Web of Science, and Embase. Eligible studies were identified and relevant data were extracted by two independent reviewers following specific eligibility criteria and a data extraction plan. Using the random-effects model, the pooled, overall and subgroup CD prevalence rates were determined, and sources of heterogeneity were investigated using meta-regression.

Results: Among a total of 1,116 screened citations, 36 eligible studies were included in the quantitative synthesis. Nearly two-thirds of the studies (61.1%) were from European countries. Of the 6,291 patients with TS who were tested for CD, 241 were diagnosed with CD, with a crude CD prevalence of 3.8%. The highest and lowest CD prevalence rates of 20.0 and 0.0% were reported in Sweden and Germany, respectively. The estimated overall weighted CD prevalence was 4.5% (95% confidence interval [CI], 3.3–5.9, I², 67.4%). The weighted serology-based CD prevalence in patients with TS (3.4%, 95% CI, 1.0–6.6) was similar to the weighted biopsy-based CD prevalence (4.8%; 95% CI, 3.4–6.5). The strength of association between TS and CD was estimated in only four studies (odds ratio 18.1, 95% CI, 1.82–180; odds ratio 4.34, 95% CI, 1.48–12.75; rate ratio 14, 95% CI, 1.48–12.75; rate ratio 42.5, 95% CI, 12.4–144.8). Given the lack of uniformity in the type of reported measures of association and study design, producing a weighted effect measure to evaluate the strength of association between TS and CD was unfeasible.

Conclusion: Nearly 1 in every 22 patients with TS had CD. Regular screening for CD in patients with TS might facilitate early diagnosis and therapeutic management to prevent adverse effects of CD such as being underweight and osteoporosis.

Acceptance of oat-based beverages tailored for patients with cancer

Oat-based beverages are a nutritious product with the potential to support increased nutrient intake of patients with cancer. The aim of this research was to evaluate the sensory acceptance of oat-based beverages and perceptions of oats among patients with cancer as future vehicles for nutrient delivery. In study 1, three flavors of oat-beverages were well accepted without significant difference in liking among flavors or serving temperature, or between patients with cancer and healthy participants. Patients with cancer more frequently rated the beverages as too sweet compared to healthy participants; flavor intensity was just about right for all participants. In the second study, one of two formulations fortified with protein and fish oil was not different in liking compared to the unfortified chocolate product. Patients associated oat food products with specific oat-based food products and oat health benefits in a free-word association task in the third study. Together, sensory acceptance and the perceived health benefits of oats indicate the potential for oats to be incorporated in fortified and unfortified products tailored for patients with cancer. PRACTICAL APPLICATION: The three studies presented here to assess the sensory acceptance of oat-based beverages and perceptions of oats among patients with cancer demonstrate that oats can be incorporated in fortified and unfortified products tailored for patients with cancer. Inadequate nutrition is highly prevalent among oncology patients and there is a lack of available products targeted to improve their nutritional intake. These findings can support product developers and sensory scientists in the development and evaluation of food products acceptable to this population.

Gas cell stabilization by aqueous-phase constituents during bread production from wheat and rye dough and oat batter: Dough or batter liquor as model system

Proper gas cell stability during fermentation and baking is essential to obtain high-quality bread. Gas cells in wheat dough are stabilized by the gluten network formed during kneading and, from the moment this network locally ruptures, by liquid films containing nonstarch polysaccharides (NSPs) and surface-active proteins and lipids. Dough liquor (DL), the supernatant after ultracentrifugation of dough, is a model system for these liquid films and has been extensively studied mostly in the context of wheat bread making. Nonwheat breads are often of lower quality (loaf volume and crumb structure) than wheat breads because their doughs/batters lack a viscoelastic wheat gluten network. Therefore, gas cell stabilization by liquid film constituents may be more important in nonwheat than in wheat bread making. This manuscript aims to review the knowledge on DL/batter liquor (BL) and its relevance for studying gas cell stabilization in wheat and nonwheat (rye and oat) bread making. To this end, the unit operations in wheat, rye, and oat bread making are described with emphasis on gas incorporation and gas cell (de)stabilization. A discussion of the knowledge on the recoveries and chemical structures of proteins, lipids, and NSPs in DLs/BLs is provided and key findings of studies dealing with foaming and air-water interfacial properties of DL/BL are discussed. Next, the extent to which DL/BL functionality can be related to bread properties is addressed. Finally, the extent to which DL/BL is a representative model system for the aqueous phase of dough/batter is discussed and related to knowledge gaps and further research opportunities.

Mediterranean Gluten-Free Diet: Is It a Fair Bet for the Treatment of Gluten-Related Disorders?

Gluten-free diet (GFD) is the current treatment of gluten-related disorders. It eliminates wheat, barley, and rye, while the exclusion of oats is still under debate. GFD is based on a combination of naturally gluten-free foods and gluten-free substitutes of cereal-based foods. Although effective as treatment of gluten-related disorders, today there is concern about how to improve GFD's nutritional quality, to make it not only gluten-free, but also healthy. The "Mediterranean diet" (MedD) refers to the dietary pattern and eating habits typical of populations living in the Mediterranean basin, which have been associated with low prevalence of several diet-related pathologies. Here we present a narrative review of the current knowledge about GFD and MedD, their characteristics and central food components. Based on the Mediterranean diet pyramid developed by the Italian pediatric society, we propose a combination between the MedD and the GFD, an attractive alternative to reach a gluten-free state that at the same time is healthy, with a clear benefit to those who practice it.

Oats as a Safe Alternative to Triticeae Cereals for People Suffering from Celiac Disease? A Review

Oats represent a promising alternative to small-grain cereals from Triticeae group (wheat, barley, rye) for persons suffering from any form of gluten intolerance, especially celiac disease (CD), since oat-specific prolamins avenins reveal generally lower gluten content and immunoreactivity. Recent studies on avenin molecular structure revealed large genetic variability in avenin sequences affecting the spectrum of gluten peptides produced by hydrolases in human digestive tract. The aim of the present review is to summarise recent knowledge obtained in laboratory studies focused on the effect of avenin-derived peptides on reactivity of crucial components of human immune system such as dendritic cells (DC) and T-cells. The other part of the review summarises the results of clinical studies with CD patients including oat products in their diet. Since different clinical studies revealed contradictory results regarding potential safety of oats for CD patients, the focus has to be directed at genetic variability in oat avenins. Identification of avenin isoforms with minimum CD immunoreactivity will open up ways leading to designing novel oat cultivars suitable for CD patients. Knowledge on immunoreactivity of gluten peptides together with breeding new oat cultivars revealing minimum avenin immunoreactivity with respect to CD as well as application of food processing technologies leading to gluten content reduction should result in development of gluten-free oats safe for celiacs.

Lactic Acid Fermentation of Cereals and Pseudocereals: Ancient Nutritional Biotechnologies with Modern Applications

Grains are a substantial source of macronutrients and energy for humans. Lactic acid (LA) fermentation is the oldest and most popular way to improve the functionality, nutritional value, taste, appearance and safety of cereal foods and reduce the energy required for cooking. This literature review discusses lactic acid fermentation of the most commonly used cereals and pseudocereals by examination of the microbiological and biochemical fundamentals of the process. The study provides a critical overview of the indispensable participation of lactic acid bacteria (LAB) in the production of many traditional, ethnic, ancient and modern fermented cereals and beverages, as the analysed literature covers 40 years. The results reveal that the functional aspects of LAB fermented foods are due to significant molecular changes in macronutrients during LA fermentation. Through the action of a vast microbial enzymatic pool, LAB form a broad spectrum of volatile compounds, bioactive peptides and oligosaccharides with prebiotic potential. Modern applications of this ancient bioprocess include the industrial production of probiotic sourdough, fortified pasta, cereal beverages and "boutique" pseudocereal bread. These goods are very promising in broadening the daily menu of consumers with special nutritional needs.

The Pros and Cons of Using Oat in a Gluten-Free Diet for Celiac Patients

A therapeutic gluten-free diet often has nutritional limitations. Nutritional qualities such as high protein content, the presence of biologically active and beneficial substances (fiber, beta-glucans, polyunsaturated fatty acids, essential amino acids, antioxidants, vitamins, and minerals), and tolerance by the majority of celiac patients make oat popular for use in gluten-free diet. The health risk of long-time consumption of oat by celiac patients is a matter of debate. The introduction of oat into the diet is only recommended for celiac patients in remission. Furthermore, not every variety of oat is also appropriate for a gluten-free diet. The risk of sensitization and an adverse immunologically mediated reaction is a real threat in some celiac patients. Several unsolved issues still exist which include the following: (1) determination of the susceptibility markers for the subgroup of celiac patients who are at risk because they do not tolerate dietary oat, (2) identification of suitable varieties of oat and estimating the safe dose of oat for the diet, and (3) optimization of methods for detecting the gliadin contamination in raw oat used in a gluten-free diet.

To Be Oats or Not to Be? An Update on the Ongoing Debate on Oats for Patients With Celiac Disease

To date, the only known effective treatment for celiac disease (CD) is a strict gluten-free diet (GFD) for life. Patients with CD often find it difficult to adhere to strict GFD. Oats, compared with wheat, barley, and rye, contain less amounts of prolamins. Inclusion of oats in a GFD might be valuable due to their nutritional and health benefits and increase of food variety. Therefore, they may potentially improve feeding diversity for these children and improve taste and satiety. We reviewed the literature to evaluate the safety of oats in CD patients. We have searched PUBMED, societal guidelines and national health authorities' recommendations. The following aspects were reviewed: gastrointestinal symptoms, malabsorption, serology including specific avenin antibodies, mucosal changes, avenin toxicity, immunogenicity of oats, and quality of life. We also referred to wheat contamination of oat products, the safe amount of oats for CD patients and the type of oats recommended. Data support that pure oats are well-tolerated by most CD patients, at moderate amounts (20-25 g/day dry rolled oats for children; 50-70 g/day for adults). Nevertheless, since the potential for sensitivity/toxicity exists, oats should be added with caution to a GFD, only after all CD symptoms including weight loss and growth disturbances have resolved, after at least 6 months of conventional GFD and probably also after normalization of serology. The need for pre exposure biopsy is unclear and should be considered on an individual basis.

Oat safety for celiac disease patients: theoretical analysis correlates adverse symptoms in clinical studies to contaminated study oats

Inclusion of oats in a gluten-free (GF) diet can provide whole grain nutritional benefits to celiac disease (CD) patients, but there has been debate regarding oat safety for these individuals. This is because of conflicting research findings, with inconsistencies attributed to varying CD subject's sensitivities to "pure" oats. Clinical trials to date have assumed oats provided to subjects to be lightly contaminated, if at all. This assumption is challenged here since oat's propensity to be "kernel" contaminated with gluten sources like wheat and barley has recently been shown to significantly complicate confirmation of a GF state. We therefore hypothesize that clinical studies may have inadvertently provided pill-like gluten kernels intermittently to study subjects, leading to adverse outcomes that could potentially explain inconsistencies between study conclusions. To test this theory, potential gluten contamination of oats used in a cross-section of 12 important oat feeding studies has been estimated, done according to descriptions of oats used, published contamination rates for various oat types, and study oat dosages. Expected gluten exposures were found to be at levels to elicit clinical effects in a large portion of CD patients, correlating with observed clinical reaction rates in those studies (P value = .0006). Estimated gluten doses were found insufficient, however, to affect morphological outcomes, whereas only 1 study had 1 case. Our analysis provides a new perspective with which to view oat safety study conclusions and justifies new clinical trials using today's higher-purity GF oats to settle the oat safety for CD patient debate.

Safety of Oats in Children with Celiac Disease: A Double-Blind, Randomized, Placebo-Controlled Trial

OBJECTIVE

To evaluate the long-term validity and safety of pure oats in the treatment of children with celiac disease.

STUDY DESIGN

This noninferiority clinical trial used a double-blind, placebo-controlled, crossover design extended over 15 months. Three hundred six children with a biopsy-proven diagnosis of celiac disease on a gluten-free diet for ≥2 years were randomly assigned to eat specifically prepared gluten-free food containing an age-dependent amount (15-40 g) of either placebo or purified nonreactive varieties of oats for 2 consecutive 6-month periods separated by washout standard gluten-free diet for 3 months. Clinical (body mass index, Gastrointestinal Symptoms Rating Scale score), serologic (IgA antitransglutaminase antibodies, and IgA anti-avenin antibodies), and intestinal permeability data were measured at baseline, and after 6, 9, and 15 months. Direct treatment effect was evaluated by a nonparametric approach using medians (95% CI) as summary statistic.

RESULTS

After the exclusion of 129 patients who dropped out, the cohort included 177 children (79 in the oats-placebo and 98 in the placebo-oats group; median, 0.004; 95% CI, -0.0002 to 0.0089). Direct treatment effect was not statistically significant for clinical, serologic, and intestinal permeability variables (body mass index: median, -0.5; 95% CI, -0.12 to 0.00; Gastrointestinal Symptoms Rating Scale score: median, 0; 95% CI, -2.5 to 0.00; IgA antitransglutaminase antibodies: median, -0.02; 95% CI, -0.25 to 0.23; IgA anti-avenin antibodies: median, -0.0002; 95% CI, -0.0007 to 0.0003; intestinal permeability test: median, 0.004; 95% CI, -0.0002 to 0.0089).

CONCLUSIONS

Pure nonreactive oat products are a safe dietary choice in the treatment of children with celiac disease.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT00808301.

Oats in healthy gluten-free and regular diets: A perspective

During the 20th century, the economic position of oats (Avena sativa L.) decreased strongly in favour of higher yielding crops including winter wheat and maize. Presently, oat represents only ~1.3% of the total world grain production, and its production system is fragmented. Nonetheless, current interest is growing because of recent knowledge on its potential benefits in food, feed and agriculture. This perspective will serve as a further impetus, with special focus on the recently valued advantages of oats in human food and health. Five approved European Food Safety Authority (EFSA) health claims apply to oats. Four relate to the oat-specific soluble fibres, the beta-glucans, and concern the maintenance and reduction of blood cholesterol, better blood glucose balance and increased faecal bulk. The fifth claim concerns the high content of unsaturated fatty acids, especially present in the endosperm, which reduces the risks of heart and vascular diseases. Furthermore, oat starch has a low glycemic index, which is favourable for weight control. Oat-specific polyphenols and avenanthramides have antioxidant and anti-inflammatory properties. Thus, oats can contribute significantly to the presently recommended whole-grain diet. Next to globulins, oats contain a small fraction of prolamin storage proteins, called 'avenins', but at a much lower quantity than gluten proteins in wheat, barley and rye. Oat avenins do not contain any of the known coeliac disease epitopes from gluten of wheat, barley and rye. Long-term food studies confirm the safety of oats for coeliac disease patients and the positive health effects of oat products in a gluten-free diet. These effects are general and independent of oat varieties. In the EU (since 2009), the USA (since 2013) and Canada (since 2015) oat products may be sold as gluten-free provided that any gluten contamination level is below 20ppm. Oats are, however, generally not gluten-free when produced in a conventional production chain, because of regular contamination with wheat, barley or rye. Therefore, establishing a separate gluten-free oat production chain requires controlling all steps in the chain; the strict conditions will be discussed. Genomic tools, including a single nucleotide polymorphism (SNP) marker array and a dense genetic map, have recently been developed and will support marker-assisted breeding. In 2015, the Oat Global initiative emerged enabling a world-wide cooperation starting with a data sharing facility on genotypic, metabolic and phenotypic characteristics. Further, the EU project TRAFOON (Traditional Food Networks) facilitated the transfer of knowledge to small- and medium-sized enterprises (SMEs) to stimulate innovations in oat production, processing, products and marketing, among others with regard to gluten-free. Finally, with focus on counteracting market fragmentation of the global oat market and production chains, interactive innovation strategies between customers (consumers) and companies through co-creation are discussed.

Indications and Use of the Gluten Contamination Elimination Diet for Patients with Non-Responsive Celiac Disease

For the majority of patients diagnosed with celiac disease, once a gluten-free diet is initiated, symptoms improve within weeks and may completely resolve in months. However, up to 30% of patients may show signs, symptoms or persistent small intestinal damage after one year on a gluten-free diet. These patients require evaluation for other common GI etiologies and assessment of their celiac disease status in order to make a diagnosis and suggest treatment. Here, we propose an approach to evaluating patients with celiac disease with persistent symptoms, persistently elevated serology, and or persistent villous atrophy despite a gluten-free diet. We detail how to diagnose and distinguish between non-responsive and refractory celiac disease. Finally, we introduce the indications for use of the gluten contamination elimination diet and provide information for practitioners to implement the diet when necessary in their practice.

Coeliac disease: review of diagnosis and management

Coeliac disease is an immune-mediated systemic disease triggered by exposure to gluten, and manifested by small intestinal enteropathy and gastrointestinal and extra-intestinal symptoms. Recent guidelines recommend a concerted use of clear definitions of the disease. In Australia, the most recent estimated prevalence is 1.2% in adult men (1:86) and 1.9% in adult women (1:52). Active case finding is appropriate to diagnose coeliac disease in high risk groups. Diagnosis of coeliac disease is important to prevent nutritional deficiency and long term risk of gastrointestinal malignancy. The diagnosis of coeliac disease depends on clinico-pathological correlation: history, presence of antitransglutaminase antibodies, and characteristic histological features on duodenal biopsy (when the patient is on a gluten-containing diet). Human leucocyte antigen class II haplotypes DQ2 or DQ8 are found in nearly all patients with coeliac disease, but are highly prevalent in the general population at large (56% in Australia) and testing can only exclude coeliac disease for individuals with non-permissive haplotypes. Adhering to a gluten free diet allows duodenal mucosal healing and alleviates symptoms. Patients should be followed up with a yearly review of dietary adherence and a health check. Non-coeliac gluten or wheat protein sensitivity is a syndrome characterised by both gastrointestinal and extra-intestinal symptoms related to the ingestion of gluten and possibly other wheat proteins in people who do not have coeliac disease or wheat allergy recognised by diagnostic tests.

The Long-Term Consumption of Oats in Celiac Disease Patients Is Safe: A Large Cross-Sectional Study

A strict gluten-free diet (GFD) can be diversified by non-contaminated oats, but there is a shortage of long-term studies concerning its safety. We compared long-term treatment outcomes and factors associated with the introduction of oats between celiac patients on a GFD with or without oats. Eight hundred sixty-nine previously diagnosed celiac patients were interviewed. The validated Gastrointestinal Symptom Rating Scale (GSRS), Psychological General Well-Being (PGWB), and Short-Form 36 Health Survey (SF-36) questionnaires were used to assess symptoms and quality of life, serological tests were performed, and results of histology were confirmed from patient records. We found the median duration of GFD to be 10 years and 82% using oats. Factors predicting the consumption of oats were diagnosis after the year 2000, advice from a dietitian, detection by screening, and mild clinical presentation. Oat consumers and non-consumers did not differ in dietary adherence (96.5% vs. 97.4%, p = 0.746), the prevalence of symptoms (22.9% vs. 22.5%, p = 0.931), positivity for endomysial antibodies (8.8% vs. 6.0%, p = 0.237), histological recovery after one year (63.1% vs. 60.0%, p = 0.773), malignancy (4.8% vs. 3.3%, p = 0.420), osteoporosis/osteopenia (9.2% vs. 11.0%, p = 0.489), or fractures (26.9% vs. 27.9%, p = 0.791). The oat consumers had better SF-36 physical role limitations and general health scores. Based on our results, the long-term consumption of oats in celiac disease patients is safe and may improve quality of life.

Gluten Contamination in Naturally or Labeled Gluten-Free Products Marketed in Italy

Background: A strict and lifelong gluten-free diet is the only treatment of celiac disease. Gluten contamination has been frequently reported in nominally gluten-free products. The aim of this study was to test the level of gluten contamination in gluten-free products currently available in the Italian market. Method: A total of 200 commercially available gluten-free products (including both naturally and certified gluten-free products) were randomly collected from different Italian supermarkets. The gluten content was determined by the R5 ELISA Kit approved by EU regulations. Results: Gluten level was lower than 10 part per million (ppm) in 173 products (86.5%), between 10 and 20 ppm in 9 (4.5%), and higher than 20 ppm in 18 (9%), respectively. In contaminated foodstuff (gluten > 20 ppm) the amount of gluten was almost exclusively in the range of a very low gluten content. Contaminated products most commonly belonged to oats-, buckwheat-, and lentils-based items. Certified and higher cost gluten-free products were less commonly contaminated by gluten. Conclusion: Gluten contamination in either naturally or labeled gluten-free products marketed in Italy is nowadays uncommon and usually mild on a quantitative basis. A program of systematic sampling of gluten-free food is needed to promptly disclose at-risk products.

Why Oats Are Safe and Healthy for Celiac Disease Patients

The water-insoluble storage proteins of cereals (prolamins) are called “gluten” in wheat, barley, and rye, and “avenins” in oat. Gluten can provoke celiac disease (CD) in genetically susceptible individuals (those with human leukocyte antigen (HLA)-DQ2 or HLA-DQ8 serotypes). Avenins are present at a lower concentration (10%–15% of total protein content) in oat as compared to gluten in wheat (80%–85%). The avenins in the genus Avena (cultivated oat as well as various wild species of which gene bank accessions were analyzed) are free of the known CD immunogenic epitopes from wheat, barley, and rye. T cells that recognize avenin-specific epitopes have been found very rarely in CD patients. CD patients that consume oats daily do not show significantly increased levels of intraepithelial lymphocyte (EIL) cells. The safety and the positive health effects of the long-term inclusion of oats in the gluten-free diet have been confirmed in long-term studies. Since 2009 (EC 41/2009) and 2013 (FDA) oat products may be sold as gluten-free in several countries provided a gluten contamination level below 20 ppm. Introduction of oats in the gluten-free diet of celiac patients is advised after the recovery of the intestine. Health effects of oat consumption are reflected in European Food Safety Authority (EFSA)- and Food and Drug Administration (FDA)-approved health claims. Oats can form a healthy, nutritious, fiber-rich, and safe complement to the gluten-free diet.

The starch-bound alpha-amylase/trypsin-inhibitors in Avena

Oat kernels exhibit an extra-soft texture, a trait recently demonstrated to be largely modulated by starch-bound tryptophan-rich 2S proteins, the vromindolines. In this study, fractionation by two-dimensional electrophoresis of starch-bound proteins in 25 oat (Avena sativa) cultivars and 11 diploid or tetraploid Avena species revealed novel 2S proteins called Avena α-amylase/trypsin-inhibitors (AATI) because of their sequence similarity with wheat α-amylase/trypsin inhibitors. Thirty-seven AATI polypeptides, about 14 kDa in size, were split into three families named AATI-1, AATI-2, and AATI-3 with different primary structures and isoelectric points. AATI-1 and AATI-2 proteins showed 55.5-60.0 % sequence similarity with wheat α-amylase inhibitors CM1, CM2, and CM16, which have been found to cause innate immunity responses in celiac disease and non-celiac gluten sensitivity. Diploid A-genome and tetraploid AC-genome oat species possess three and five genes encoding for the AATI proteins, respectively, whereas hexaploid A. sativa exhibits 12 genes dispersed over the A-, C-, and D-genomes. Some AATI proteins expressed in hexaploid oats were assigned to the A-genome based on similarity to their counterparts in diploid species, contributing to further clarify the genetic origin of hexaploid oats. Moreover, AATI may interact with starch-bound vromindolines in determining the extra-soft texture of oat kernels and, due to their balanced amino acid compositions, may contribute to the biological value of oat proteins in a positive manner.