Long-term consumption of oats in adult celiac disease patients

Celiac Disease, Gluten Sensitivity, and Diet Management

PURPOSE OF REVIEW

Celiac disease is a common chronic inflammatory condition of the small bowel triggered by gluten in wheat, rye and barley in the diet. Non-celiac gluten sensitivity presents with symptoms similar to celiac disease with the ingestion of gluten or other components of wheat. In this article, we review challenges presented by a gluten free diet for the treatment of both disorders.

RECENT FINDINGS

Wheat is ubiquitous in the diet and medications/products. A registered dietitian is mandatory for patient education on the gluten free diet. Naturally gluten free foods provide a healthy diet for those with celiac disease. Whole grains labelled gluten free, including oats, are encouraged in the diet as refined grains may be deficient in fiber, protein, and micronutrients, particularly folate. Gluten contamination is the most common cause of persistent symptoms in celiac disease though shared equipment of food preparation may not be as large a problem as suspected. Most with celiac disease on a gluten free diet will fully recover and gain weight that poses a problem for those overweight to start. The gluten free diet may have a negative impact on quality of life for both celiac patients and their families. Those with hypervigilance of the gluten free diet and avoidance of dining out have the lowest quality of life. The gluten free diet is currently the only effective treatment for celiac disease. A registered dietitian is needed to educate patients on the complexity of the gluten free diet with a goal of healthy eating, maintaining a healthy weight, and avoiding disordered eating or diet hypervigilance; key to a good quality of life.

Celiac Disease: An Academy of Nutrition and Dietetics Evidence-Based Nutrition Practice Guideline

Celiac disease is an autoimmune disorder in which the immune system of genetically susceptible individuals elicits a reaction to gluten causing small intestine damage. If left undiagnosed and untreated, the resulting nutrition malabsorption can lead to anemia, bone disease, growth faltering, or other consequences. The condition is lifelong and lacks a cure; the only treatment is lifelong adherence to a gluten-free diet (GFD). This diet is challenging to follow and adversely influences quality of life; however, it is essential to ensure intestinal recovery and prevent future negative health consequences. The Academy of Nutrition and Dietetics convened an expert panel complemented by a celiac disease patient advocate to evaluate evidence for six topics, including medical nutrition therapy; the GFD; oat consumption; micronutrients; pro-/prebiotics; and the low fermentable oligosaccharides, disaccharides, monosaccharides, and polyols diet. This publication outlines the Academy of Nutrition and Dietetics Evidence Analysis Library methods used to complete the systematic review and guideline development, and summarizes the recommendations and supporting evidence. The guidelines affirm that all individuals with celiac disease should follow a GFD (1C, Imperative) that may include gluten-free oats in adults (2D, Conditional). Children should follow a nutritionally adequate GFD that supports healthy growth and development (Consensus, Imperative) and does not unnecessarily restrict gluten-free oats (Consensus, Conditional). The guidelines indicate nutritional care should include routine nutritional assessment (Consensus, Imperative) and medical nutrition therapy (Consensus, Imperative). At this time, the guidelines do not support a recommendation for the addition of the low fermentable oligosaccharides, disaccharides, monosaccharides, and polyols diet (2C, Conditional); prebiotic or probiotic supplementation (2D, Conditional); or micronutrient supplementation (in the absence of nutritional deficiency) (Consensus, Conditional). The 2021 Celiac Disease Evidence-Based Nutrition Guideline will assist registered dietitian nutritionists in providing appropriate evidence-based medical nutrition therapy to support people with celiac disease in achieving and maintaining nutritional health and avoiding adverse celiac disease consequences throughout their lives.

Fermented Oats as a Novel Functional Food

Fermented oats are gaining popularity due to their nutritional value and the increasing consumer demand for health-conscious foods. These oats are believed to offer enhanced phytochemical and nutritional profiles compared to unfermented oats. The increased nutritional content of fermented oats is associated with various health benefits, including anti-inflammatory and antioxidant activities, which could potentially reduce the risk of chronic diseases. Further investigations are warranted to elucidate the nutritional benefits of fermented oats in human nutrition. This mini review provides a comprehensive overview of fermented oat products available on the market and the various production methods employed for fermenting oats. Furthermore, this review investigates how fermentation affects the chemical composition and biological functions of oats. Additionally, this manuscript presents some future perspectives on fermented oat products by discussing potential research directions and opportunities for further development. The findings presented in this review contribute to the expanding body of knowledge on fermented oats as a promising functional food, paving the way for future studies and applications in the field of nutrition and health.

ESPEN guideline on hospital nutrition

In hospitals through Europe and worldwide, the practices regarding hospital diets are very heterogeneous. Hospital diets are rarely prescribed by physicians, and sometimes the choices of diets are based on arbitrary reasons. Often prescriptions are made independently from the evaluation of nutritional status, and without taking into account the nutritional status. Therapeutic diets (low salt, gluten-free, texture and consistency modified, …) are associated with decreased energy delivery (i.e. underfeeding) and increased risk of malnutrition. The European Society for Clinical Nutrition and Metabolism (ESPEN) proposes here evidence-based recommendations regarding the organization of food catering, the prescriptions and indications of diets, as well as monitoring of food intake at hospital, rehabilitation center, and nursing home, all of these by taking into account the patient perspectives. We propose a systematic approach to adapt the hospital food to the nutritional status and potential food allergy or intolerances. Particular conditions such as patients with dysphagia, older patients, gastrointestinal diseases, abdominal surgery, diabetes, and obesity, are discussed to guide the practitioner toward the best evidence based therapy. The terminology of the different useful diets is defined. The general objectives are to increase the awareness of physicians, dietitians, nurses, kitchen managers, and stakeholders towards the pivotal role of hospital food in hospital care, to contribute to patient safety within nutritional care, to improve coverage of nutritional needs by hospital food, and reduce the risk of malnutrition and its related complications.

A Review of Health-Beneficial Properties of Oats

Oat is among the food crops and ancient grains cultivated and consumed worldwide. It is gaining in popularity owing to its nutritional composition and multifunctional benefits of select bioactive compounds. Beta-glucan is an important component of dietary fiber found in oat grains. It is the major active compound in oats with proven cholesterol-lowering and antidiabetic effects. Oats also provide substantial levels of other bioactive compounds such as phenolic acids, tocols, sterols, avenacosides, and avenanthramides. The consumption of oats has been determined to be beneficial for human health by promoting immunomodulation and improving gut microbiota. In addition, oat consumption assists in preventing diseases such as atherosclerosis, dermatitis, and some forms of cancer. While much has been published in relation to oat nutrients and oat fibers and their impact on major diseases, the oat industries and consumers may benefit from greater knowledge and understanding of clinical effects, range of occurrence, distribution, therapeutic doses and food functional attributes of other oat bioactives such as avenanthramides and saponins as well as other anti-inflammatory agents found in the cereal. This review focuses on the various studies relevant to the contribution of the consumption of oats and oat-based products in preventing human diseases and promoting human health.

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.

Systematic Review of the Effects of Oat Intake on Gastrointestinal Health

BACKGROUND

Oats are a food source with multiple health benefits that could support beneficial bacterial groups and provide important bioactive compounds for the gut.

OBJECTIVES

This review explores the association between oat intake, gastrointestinal (GI) symptoms, and microbial community changes in individuals with celiac disease (CeD), irritable bowel syndrome (IBS), and inflammatory bowel disease (IBD) and without GI disease.

METHODS

Four databases and Google Scholar were systematically searched from inception until April 29, 2021. Clinical trials, observational studies, and in vitro studies with human gut-derived samples were included.

RESULTS

There were 84 articles [23 randomized controlled trials (RCTs), 21 nonrandomized trials, 8 observational studies, and 32 in vitro studies] included. Oat intake increased total bacterial count, Lactobacilli spp., and Bifidobacterium spp. in healthy individuals and those with CeD. There was an increased concentration of short-chain fatty acids and improved gut permeability with oat intake but with no significant quality-of-life difference. In some individuals with CeD, consumption of certain oat types was associated with worsening of GI symptoms. We found no studies reporting on IBS and only 3 for IBD. The quality of RCTs showed some concerns mostly in domains of randomization (73.9%), whereas the quality of evidence of non-RCTs, observational studies, and in vitro studies was satisfactory.

CONCLUSIONS

Oat intake was associated with the increase of beneficial bacterial groups in individuals without GI disease and those with CeD. Most studies showed no changes in GI symptoms with oat consumption. In vitro studies in CeD provide insight to oat-sensitive individuals and their GI mucosa, but the clinical studies remain limited, precluding our ability to draw firm conclusions. The prevalence of oat sensitivity in individuals with CeD should be further explored as this could improve clinical management and facilitate inclusion of oat in the diet for this population.

A Novel Sprouted Oat Fermented Beverage: Evaluation of Safety and Health Benefits for Celiac Individuals

The safety and health effects for celiac people of a novel beverage (SOFB) developed from sprouted oat flour by fermentation with Lactobacillus plantarum was explored. In vitro reactivity against anti-gliadin antibodies (AGA) and antioxidant/anti-inflammatory potential of SOFB in RAW 264.7 macrophages and Caco-2 cells were evaluated. Immunoreactivity against AGA and antioxidant activity were not detected in SOFB, but it exhibited significant anti-inflammatory activity. The tolerability and impact of SOFB consumption for 6 months on nutritional status and intestinal microbiota composition were investigated in 10 celiac adults (five treated and five control). SOFB consumption did not adversely affect duodenal mucosa nor the total IgA or anti-tissue transglutaminase antibody (IgA-tTG) levels in celiac participants, but it significantly decreased total cholesterol levels at all sampling times and folic acid levels at the end of the study compared to the placebo beverage. SOFB administration also shifted gut microbiota, leading to a higher relative abundance of some beneficial bacteria including the genera Subdoligranulum, Ruminococcus and Lactobacillus in the SOFB group. This study provides supporting evidence of the safety of health benefits of a novel functional beverage produced from sprouted oat.

Effect of Oat β-Glucan on Affective and Physical Feeling States in Healthy Adults: Evidence for Reduced Headache, Fatigue, Anxiety and Limb/Joint Pains

The gastrointestinal (GI) side-effects of dietary fibers are recognized, but less is known about their effects on non-GI symptoms. We assessed non-GI symptoms in a trial of the LDL-cholesterol lowering effect of oat β-glucan (OBG). Participants (n = 207) with borderline high LDL-cholesterol were randomized to an OBG (1 g OBG, n = 104, n = 96 analyzed) or Control (n = 103, n = 95 analyzed) beverage 3-times daily for 4 weeks. At screening, baseline, 2 weeks and 4 weeks participants rated the severity of 16 non-GI symptoms as none, mild, moderate or severe. The occurrence and severity (more or less severe than pre-treatment) were compared using chi-squared and Fisher's exact test, respectively. During OBG treatment, the occurrence of exhaustion and fatigue decreased versus baseline (p < 0.05). The severity of headache (2 weeks, p = 0.032), anxiety (2 weeks p = 0.059) and feeling cold (4 weeks, p = 0.040) were less on OBG than Control. The severity of fatigue and hot flashes at 4 weeks, limb/joint pain at 2 weeks and difficulty concentrating at both times decreased on OBG versus baseline. High serum c-reactive-protein and changes in c-reactive-protein, oxidized-LDL, and GI-symptom severity were associated with the occurrence and severity of several non-GI symptoms. These data provide preliminary, hypothesis-generating evidence that OBG may reduce several non-GI symptoms in healthy adults.

Ancient and Modern Cereals as Ingredients of the Gluten-Free Diet: Are They Safe Enough for Celiac Consumers?

Celiac disease is an autoimmune disorder that occurs in genetically predisposed individuals after consuming prolamins from some cereals. Although the products available for celiac subjects have increased significantly in quality and quantity over the last few decades, research still focuses on identifying new ingredients to improve the nutritional, sensorial and functional qualities of gluten-free products. In terms of toxicity for people with celiac disease, there is a wide variability between ancient and modern grains. The most contradictory results are related to the role of oats in the gluten-free diet. In order to clarify the role of minor cereals (such as oat) and ancient grains in the diets of celiac patients, this review discusses recent in vitro and in vivo studies performed on those cereals for which the toxicity for celiac subjects is still controversial. According to in vivo studies, selected oat varieties could be tolerated by celiac patients. On the other hands, although some wheat-ancient grains (Triticum monococcum, Triticum aestivum ssp. spelta and Kamut^®) showed a reduced in vitro toxicity, to date, these grains are still considered toxic for celiac patients. Contradictory results underline the importance of studying the safety of "unusual" cereals in more detail.

Diet, Perceived Intestinal Well-Being and Compositions of Fecal Microbiota and Short Chain Fatty Acids in Oat-Using Subjects with Celiac Disease or Gluten Sensitivity

A gluten-free diet may result in high fat and low fiber intake and thus lead to unbalanced microbiota. This study characterized fecal microbiota profiles by 16S MiSeq sequencing among oat-using healthy adult subjects (n = 14) or adult subjects with celiac disease (CeD) (n = 19) or non-celiac gluten sensitivity (NCGS) (n = 10). Selected microbial metabolites, self-reported 4d food diaries and perceived gut symptoms were compared. Subjects with NCGS experienced the highest amount of gut symptoms and received more energy from fat and less from carbohydrates than healthy and CeD subjects. Oat consumption resulted in reaching the lower limit of the recommended fiber intake. Frequent consumption of gluten-free pure oats did not result in microbiota dysbiosis in subjects with CeD or NCGS. Thus, the high number of gut symptoms in NCGS subjects was not linked to the microbiota. The proportion of fecal acetate was higher in healthy when compared to NCGS subjects, which may be linked to a higher abundance of Bifidobacterium in the control group compared to NCGS and CeD subjects. Propionate, butyrate and ammonia production and β-glucuronidase activity were comparable among the study groups. The results suggest that pure oats have great potential as the basis of a gluten-free diet and warrant further studies in minor microbiota disorders.

Effects of oats on gastrointestinal health as assessed by in vitro, animal, and human studies

Oats are uniquely nutritious, owing to their composition of bioactive compounds, lipids, and β-glucan. Scientific research has established that oats can improve diet quality, reduce cholesterol, regulate satiety, and protect against carcinogenesis in the colon; however, determining the effects of oats on gastrointestinal health and the gut microbiome is a newer, evolving area of research. To better understand the effects of oats on gastrointestinal health in humans, a literature review with predefined search criteria was conducted using the PubMed database and keywords for common gastrointestinal health outcomes. Moreover, to examine the gastrointestinal effects of oats across the scientific spectrum, a similar search strategy was executed to identify animal studies. In vitro studies were identified from the reference lists of human and animal studies. A total of 8 human studies, 19 animal studies, and 5 in vitro studies met the inclusion criteria for this review. The evidence in humans shows beneficial effects of oats on gastrointestinal health, with supportive evidence provided by in vitro and animal studies. The effective dose of oats varies by type, although an amount providing 2.5 to 2.9 g of β-glucan per day was shown to decrease fecal pH and alter fecal bacteria. For oat bran, 40 to 100 g/d was shown to increase fecal bacterial mass and short-chain fatty acids in humans. Differences in study design, methodology, and type of oats tested make valid comparisons difficult. The identification of best practices for the design of oat studies should be a priority in future research, as the findings will be useful for determining how oats influence specific indices of gastrointestinal health, including the composition of the human gut microbiome.

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.

The Long-Term Safety and Quality of Life Effects of Oats in Dermatitis Herpetiformis

The treatment of choice for dermatitis herpetiformis (DH), a cutaneous manifestation of coeliac disease, is a life-long gluten-free diet (GFD). In a GFD, wheat, rye and barley should be strictly avoided, but the role of oats is more controversial. This study aimed to investigate the safety and long-term quality of life and health effects of oat consumption in 312 long-term treated DH patients. Baseline data were gathered from patient records and follow-up data from questionnaires or interviews, and validated questionnaires were used to assess quality of life. We found that altogether 256 patients (82%) were consuming oats as part of their GFD at the follow-up. Long-term follow-up data showed that there were no differences in the presence of long-term illnesses, coeliac disease complications or the usage of medication between those consuming and not consuming oats. However, oat consumers had a better quality of life and reported ongoing gastrointestinal symptoms less frequently (4% vs 19%, p = 0.004) at the follow-up than those not consuming oats. The study established that oats are safe for DH patients and in the long-term seem to improve the quality of life of DH patients.

Nutrition Assessment, Interventions, and Monitoring for Patients with Celiac Disease: An Evidence Analysis Center Scoping Review

The objectives of this scoping review were to identify and characterize studies examining nutrition assessment, interventions, and measures to monitor gluten-free diet (GFD) adherence/compliance in patients with celiac disease (CD). An electronic literature search of four databases (Cochrane Database for systematic reviews, CINAHL, Embase, and Ovid MEDLINE) was conducted to identify articles examining nutrition care in CD individuals. Except for narrative review, grey literature, and case study/report, all types of peer-reviewed articles published between January 2007 and August 2018 were eligible. There were a total of 10,823 records; 10,368 were excluded during the first round of screening due to irrelevancy and/or duplication. Of the 455 full-text articles that were assessed, 292 met the criteria and were included. Most of the studies were observational studies (n=212), followed by experimental trials (n=50), evidence-based practice guideline (EBPG)/report/statement (n=16), and systematic review (SR) (n=14). Nine original studies examined assessment, focusing mainly on different tools/ways to assess GFD adherence. The majority of the included original articles (n=235) were in the nutrition intervention category with GFD, oats, and prebiotics/probiotics as the top-three most studied interventions. There were eight SRs on GFD and five on oats. One SR and 21 original studies investigated the effectiveness of different measures to monitor GFD adherence/compliance. Although recent CD EBPGs were identified, different methods with varying levels of rigor, in terms of literature search and assessment of evidence strength, were used. Based on this scoping review, interventions focused on gluten-free diet and oats have been significantly covered by either SRs or EBPGs. Studies related to prebiotics/probiotics and education program/counseling focused interventions, as well as assessment, in CD patients have increased in recent years. Thus, it might be beneficial to conduct SRs/EBPGs focused on these topics to guide practitioners.

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.

Analysis of avenanthramides in oat products and estimation of avenanthramide intake in humans

Avenanthramides are phenolic compounds found only in oats, and are of interest due to suggested bioactivities, including anti-inflammatory effects and induction of apoptosis. The objective of this work was to optimise a high performance liquid chromatography (HPLC) method for analysis of avenanthramides in food, and analyse the avenanthramide content in 45 oat fractions and products. The optimised HPLC method was based on triplicate extraction of 100 mg sample with 1 ml 80% ethanol in phosphate buffer (pH 2.8) and used gallacetophenone as an internal standard. Avenalumic acid-derived avenanthramide homologues 2f_d and 2p_d were also present, making up to 20% of the total avenanthramides detected in oats. The amounts of avenanthramides detected in oat products was 2-82 µg/g. It was estimated that mean avenanthramide intake among oat consumers ranges from 0.3 to 2.1 mg/day, considerably lower than the amount used in studies that have investigated biological effects of avenanthramides in humans.

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.

The Gluten-Free Diet: Can Oats and Wheat Starch Be Part of It?

Objective and Conclusion: Uncertainty still exists about the use of oats and wheat starch as part of a gluten-free diet in patients with celiac disease (CD). This review should help to clarify the issues at hand. Whereas uncontaminated (from gluten/gliadin) oats and oats from cultivars not containing celiac-activating sequences of proline and glutamine can be used without risk of intestinal damage, wheat starch should not be used, unless it is free of gluten-that is, deglutinized-because even small amounts of gluten over time are able to induce small intestinal mucosal damage.

Safety of Adding Oats to a Gluten-Free Diet for Patients With Celiac Disease: Systematic Review and Meta-analysis of Clinical and Observational Studies

BACKGROUND & AIMS

Patients with celiac disease should maintain a gluten-free diet (GFD), excluding wheat, rye, and barley. Oats might increase the nutritional value of a GFD, but their inclusion is controversial. We performed a systematic review and meta-analysis to evaluate the safety of oats as part of a GFD in patients with celiac disease.

METHODS

We searched the Cochrane Central Register of Controlled Trials, MEDLINE, and EMBASE databases for clinical trials and observational studies of the effects of including oats in GFD of patients with celiac disease. The studies reported patients' symptoms, results from serology tests, and findings from histologic analyses. We used the GRADE approach to assess the quality of evidence.

RESULTS

We identified 433 studies; 28 were eligible for analysis. Of these, 6 were randomized and 2 were not randomized controlled trials comprising a total of 661 patients-the remaining studies were observational. All randomized controlled trials used pure/uncontaminated oats. Oat consumption for 12 months did not affect symptoms (standardized mean difference: reduction in symptom scores in patients who did and did not consume oats, -0.22; 95% CI, -0.56 to 0.13; P = .22), histologic scores (relative risk for histologic findings in patients who consumed oats, 0.24; 95% CI, 0.01-4.8; P = .35), intraepithelial lymphocyte counts (standardized mean difference, 0.21; 95% CI, reduction of 1.44 to increase in 1.86), or results from serologic tests. Subgroup analyses of adults vs children did not reveal differences. The overall quality of evidence was low.

CONCLUSIONS

In a systematic review and meta-analysis, we found no evidence that addition of oats to a GFD affects symptoms, histology, immunity, or serologic features of patients with celiac disease. However, there were few studies for many endpoints, as well as limited geographic distribution and low quality of evidence. Rigorous double-blind, placebo-controlled, randomized controlled trials, using commonly available oats sourced from different regions, are needed.

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.

Performing routine follow-up biopsy 1 year after diagnosis does not affect long-term outcomes in coeliac disease

BACKGROUND

A repeat biopsy is recommended, but often omitted in coeliac disease patients on a gluten-free diet. The effect of performing or not performing repeat biopsies is currently unknown.

AIM

To identify factors associated with and the significance of lacking biopsy for long-term outcome. Predictors and the importance of incomplete histological recovery after 1 year was investigated in re-biopsied patients.

METHODS

A total of 760 patients participated in a nationwide follow-up study. Medical data were gathered via interviews and patient records, and blood samples were drawn for serology. Current symptoms and well-being were assessed by validated PGWB, SF-36 and GSRS questionnaires.

RESULTS

Malabsorption was more common among those with a repeat biopsy (46%) than those without repeat biopsy (33%), P < 0.001, as were severe symptoms at diagnosis (24% vs. 16%, P = 0.05) and concomitant gastrointestinal (40% vs. 32%, P = 0.049) or musculoskeletal (35% vs. 27%, P = 0.023) diseases such as arthritis, osteoporosis and back pain. Repeat biopsy was more rare in subjects diagnosed in private care (11% vs. 23%, P < 0.001) or by screening (10% vs. 16%, P = 0.010). The groups were comparable as to current symptoms and dietary adherence, but those without re-biopsy were less confident of their diet (89% vs. 94%, P = 0.002) and more often seropositive on diet (14% vs. 9%, P = 0.012). They reported better SF-36 physical functioning (P = 0.043) and less pain and indigestion (P = 0.013 and P = 0.046 respectively) and total GSRS (P = 0.052) score. Incomplete mucosal recovery was predicted by more advanced histological (P < 0.001) and serological (P = 0.001) disease at diagnosis, whereas the groups did not differ in long-term adherence, symptoms, seropositivity, questionnaire scores, frequency of fractures or malignancies.

CONCLUSIONS

Severe disease at diagnosis predicted the record of a repeat biopsy and incomplete mucosal recovery. Neither lacking biopsy nor incomplete recovery in a relative short time span of 1 year was associated with poorer long-term outcome, although survival bias cannot be excluded.

Food processing and breeding strategies for coeliac-safe and healthy wheat products

A strict gluten-free diet is currently the only treatment for the 1-2% of the world population who suffer from coeliac disease (CD). However, due to the presence of wheat and wheat derivatives in many food products, avoiding gluten consumption is difficult. Gluten-free products, made without wheat, barley or rye, typically require the inclusion of numerous additives, resulting in products that are often less healthy than gluten-based equivalents. Here, we present and discuss two broad approaches to decrease wheat gluten immunogenicity for CD patients. The first approach is based on food processing strategies, which aim to remove gliadins or all gluten from edible products. We find that several of the candidate food processing techniques to produce low gluten-immunogenic products from wheat already exist. The second approach focuses on wheat breeding strategies to remove immunogenic epitopes from the gluten proteins, while maintaining their food-processing properties. A combination of breeding strategies, including mutation breeding and possibly genome editing, will be necessary to produce coeliac-safe wheat. Individuals suffering from CD and people genetically susceptible who may develop CD after prolonged gluten consumption would benefit from reduced CD-immunogenic wheat. Although the production of healthy and less CD-toxic wheat varieties and food products will be challenging, increasing global demand may require these issues to be addressed in the near future by food processing and cereal breeding companies.

Diagnostic and Research Aspects of Small Intestinal Disaccharidases in Coeliac Disease

Disaccharidases (DS) are brush border enzymes embedded in the microvillous membrane of small intestinal enterocytes. In untreated coeliac disease (CD), a general decrease of DS activities is seen. This manuscript reviews different aspects of DS activities in CD: their utility in the diagnosis and their application to in vitro toxicity testing. The latter has never been established in CD research. However, with the recent advances in small intestinal organoid techniques, DS might be employed as a biomarker for in vitro studies. This includes establishment of self-renewing epithelial cells raised from tissue, which express differentiation markers, including the brush border enzymes. Determining duodenal DS activities may provide additional information during the diagnostic workup of CD: (i) quantify the severity of the observed histological lesions, (ii) provide predictive values for the grade of mucosal villous atrophy, and (iii) aid diagnosing CD where minor histological changes are seen. DS can also provide additional information to assess the response to a gluten-free diet as marked increase of their activities occurs four weeks after commencing it. Various endogenous and exogenous factors affecting DS might also be relevant when considering investigating the role of DS in other conditions including noncoeliac gluten sensitivity and DS deficiencies.

Characterization of celiac disease related oat proteins: bases for the development of high quality oat varieties suitable for celiac patients

Some studies have suggested that the immunogenicity of oats depends on the cultivar. RP-HPLC has been proposed as a useful technique to select varieties of oats with reduced immunogenicity. The aim of this study was to identify both the avenin protein patterns associated with low gluten content and the available variability for the development of new non-toxic oat cultivars. The peaks of alcohol-soluble avenins of a collection of landraces and cultivars of oats have been characterized based on the RP-HPLC elution times. The immunotoxicity of oat varieties for patients with celiac disease (CD) has been tested using a competitive ELISA based on G12 monoclonal antibody. The oat lines show, on average, seven avenin peaks giving profiles with certain similarities. Based on this similarity, most of the accessions have been grouped into avenin patterns. The variability of RP-HPLC profiles of the collection is great, but not sufficient to uniquely identify the different varieties of the set. Overall, the immunogenicity of the collection is less than 20 ppm. However, there is a different distribution of toxicity ranges between the different peak patterns. We conclude that the RP-HPLC technique is useful to establish groups of varieties differing in degree of toxicity for CD patients.

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.

Pure Oats as Part of the Canadian Gluten-Free Diet in Celiac Disease: The Need to Revisit the Issue

The question about recommending pure, noncontaminated oats as part of the gluten-free diet of patients with celiac disease remains controversial. This might be due to gluten cross contamination and to the possible immunogenicity of some oat cultivars. In view of this controversy, a review of the scientific literature was conducted to highlight the latest findings published between 2008 and 2014 to examine the current knowledge on oats safety and celiac disease in Europe and North America. Results showed that regular oats consumed in Canada are largely contaminated. Overall, the consumption of pure oats has been generally considered to be safe for adults and children. However, it appears that some oat cultivars may trigger an immune response in sensitive individuals. Therefore, further long-term studies on the impact of consumption of oats identifying the cultivar(s) constitute an important step forward for drawing final recommendations. Furthermore, a closer and more accurate monitoring of the dietary intake of noncontaminated oats would be paramount to better determine what its actual contribution in the gluten-free diet of adults and children with celiac disease are in order to draw sound recommendations on the safety of pure oats as part of the gluten-free diet.

Identification and molecular characterization of oat peptides implicated on coeliac immune response

BACKGROUND

Oats provide important nutritional and pharmacological properties, although their safety in coeliac patients remains controversial. Previous studies have confirmed that the reactivity of the anti-33-mer monoclonal antibody with different oat varieties is proportional to the immune responses in terms of T-cell proliferation. Although the impact of these varieties on the adaptive response has been studied, the role of the dendritic cells (DC) is still poorly understood. The aim of this study is to characterize different oat fractions and to study their effect on DC from coeliac patients.

METHODS AND RESULTS

Protein fractions were isolated from oat grains and analyzed by SDS-PAGE. Several proteins were characterized in the prolamin fraction using immunological and proteomic tools, and by Nano-LC-MS/MS. These proteins, analogous to α- and γ-gliadin-like, showed reactive sequences to anti-33-mer antibody suggesting their immunogenic potential. That was further confirmed as some of the newly identified oat peptides had a differential stimulatory capacity on circulating DC from coeliac patients compared with healthy controls.

CONCLUSIONS

This is the first time, to our knowledge, where newly identified oat peptides have been shown to elicit a differential stimulatory capacity on circulating DC obtained from coeliac patients, potentially identifying immunogenic properties of these oat peptides.

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

This paper provides an overview of the latest scientific data related to the safety of uncontaminated oats (<20 ppm of gluten) in the diet of individuals with celiac disease (CD). It updates the previous Health Canada position posted on the Health Canada website in 2007 and a related paper published in 2009. It considers a number of recent studies published between January 2008 and January 2015. While recognizing that a few people with celiac disease seem to be clinically intolerant to oats, this review concludes that oats uncontaminated by gluten-containing cereals (wheat, rye, and barley) can be safely ingested by most patients with celiac disease and that there is no conclusive evidence that the consumption of uncontaminated or specially produced oats containing no greater than 20 ppm gluten by patients with celiac disease should be limited to a specific daily amount. However, individuals with CD should observe a stabilization phase before introducing uncontaminated oats to the gluten-free diet (GFD). Oats uncontaminated with gluten should only be introduced after all symptoms of celiac disease have resolved and the individual has been on a GFD for a minimum of 6 months. Long-term regular medical follow-up of these patients is recommended but this is no different recommendation to celiac individuals on a GFD without oats.

Role of oats in celiac disease

A gluten-free diet is currently the only effective means of treating individuals with celiac disease. Such a diet enables celiac patients to control their symptoms and avoid various complications associated with this condition. However, while the quality of gluten-free foods has significantly improved during recent decades, maintenance of a gluten-free diet does not necessarily ensure adequate nutritional intake. Because oats are an important source of proteins, lipids, vitamins, minerals, and fibre, their inclusion in a gluten-free diet might improve the nutritional status of a celiac patient. Although oats are included in the list of gluten-free ingredients specified in European regulations, their safety when consumed by celiac patients remains debatable. Some studies claim that pure oats are safe for most celiac people, and contamination with other cereal sources is the main problem facing people with this disease. However, it is necessary to consider that oats include many varieties, containing various amino acid sequences and showing different immunoreactivities associated with toxic prolamins. As a result, several studies have shown that the immunogenicity of oats varies depending on the cultivar consumed. Thus, it is essential to thoroughly study the variety of oats used in a food ingredient before including it in a gluten-free diet.

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.

Selenium in Gluten-free Products

The nutritional value of gluten-free products is the subject of interest for food technologists and nutritionists, as the only effective treatment for celiac disease is a lifelong gluten-free diet. As selenium deficiencies in celiac disease are observed, the aim of the study was to determine the selenium content in 27 grain gluten-free products available on the European Union (EU) market. Moreover, selenium content in products based on popular gluten-free cereals like corn, rice, and buckwheat and in relatively new or less popular products based on oat, amaranth, teff, and quinoa was compared. Selenium content in the tested products ranged from 0.9 to 24.5 μg/100 g. The average content of selenium in products based on popular gluten-free cereals was 2.8 μg/100 g and in products based on oat, amaranth, teff, and quinoa was 10.8 μg/100 g. It indicates that products based on less popular grains, especially on oat, should be more frequently chosen as a source of selenium by people on gluten-free diet than traditionally consumed gluten-free grains.

Ingestion of oats and barley in patients with celiac disease mobilizes cross-reactive T cells activated by avenin peptides and immuno-dominant hordein peptides

Celiac disease (CD) is a common CD4(+) T cell mediated enteropathy driven by gluten in wheat, rye, and barley. Whilst clinical feeding studies generally support the safety of oats ingestion in CD, the avenin protein from oats can stimulate intestinal gluten-reactive T cells isolated from some CD patients in vitro. Our objective was to establish whether ingestion of oats or other grains toxic in CD stimulate an avenin-specific T cell response in vivo. We fed participants a meal of oats (100 g/day over 3 days) to measure the in vivo polyclonal avenin-specific T cell responses to peptides contained within comprehensive avenin peptide libraries in 73 HLA-DQ2.5(+) CD patients. Grain cross-reactivity was investigated using oral challenge with wheat, barley, and rye. Avenin-specific responses were observed in 6/73 HLA-DQ2.5(+) CD patients (8%), against four closely related peptides. Oral barley challenge efficiently induced cross-reactive avenin/hordein-specific T cells in most CD patients, whereas wheat or rye challenge did not. In vitro, immunogenic avenin peptides were susceptible to digestive endopeptidases and showed weak HLA-DQ2.5 binding stability. Our findings indicate that CD patients possess T cells capable of responding to immuno-dominant hordein epitopes and homologous avenin peptides ex vivo, but the frequency and consistency of these T cells in blood is substantially higher after oral challenge with barley compared to oats. The low rates of T cell activation after a substantial oats challenge (100 g/d) suggests that doses of oats commonly consumed are insufficient to cause clinical relapse, and supports the safety of oats demonstrated in long-term feeding studies.

Celiac disease: the search for adjunctive or alternative therapies

Celiac disease is a widespread disorder caused by intolerance to gluten, a common protein in food. Currently, a life-long gluten-free diet is the only available treatment for patients with celiac disease. However, adherence to gluten-free diet is difficult due to the widespread use of wheat-derived gluten in the food industry. Therefore, there is a pressing need for the development of novel non-dietary therapies. In this article, we will review several promising strategies focusing on reducing gluten immunogenicity or sequestering to gluten prevent its uptake by the intestinal epithelium. Other possible treatment strategies that will be reviewed include the suppression of the adaptive immune response, permeability modulation and the use of systemic T-cell or cytokine blockers.