Lack of cellular and humoral immunological responses to oats in adults with coeliac disease

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.

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.

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.

Assessment of Avenins from Different Oat Varieties Using R5-Based Sandwich ELISA

Gluten derived from wheat and related triticeae cereals possesses distinct amino acid sequences that provoke the immunopathogenic features of celiac disease (CD) in genetically susceptible individuals. However, the role of oat-derived gluten, or avenins, in CD pathogenesis remains a disputed matter, as evidenced by a lack in harmonized legislation regarding gluten classification in relation to gluten-free labeling. In this study, we have analyzed a panel of pure oat cultivars using a sandwich ELISA based on the R5 monoclonal antibody (mAb), which binds to canonical epitopes occurring within celiagenic peptides present in triticeae-derived gluten but reportedly not present in avenins. We have identified three varieties of oats that reproducibly bind R5 antibodies and levels indicating the presence of gluten at more than the 20 ppm gluten regulatory threshold. Nested assessment using Western blot analysis and alternative gluten detection systems corroborated these results. Collectively, these data suggest that select oat varieties may prove problematic to patients with CD and to food companies and regulatory agencies and will extend our basic understanding of current gluten detection systems.

Oats and bowel disease: a systematic literature review

Whole-grain foods such as oats may protect against colorectal cancer and have benefits on inflammatory bowel disease and coeliac disease. The present study aimed to systematically review the literature describing intervention studies that investigated the effects of oats or oat bran on risk factors for bowel disease. A literature search was conducted using Embase, Medline and the Cochrane library, which identified 654 potential articles. Thirty-eight articles describing twenty-nine studies met the inclusion criteria. Two studies carried out in participants with a history of colorectal adenomas found no effects of increased oat-bran intake on indirect risk makers for colorectal cancer. One of two interventions with oat bran in patients with ulcerative colitis showed small improvements in the patients' conditions. Most of the eleven studies carried out in adults with coeliac disease showed no negative effects of uncontaminated oat consumption. The fourteen studies carried out in volunteers with no history of bowel disease suggest that oats or oat bran can significantly increase stool weight and decrease constipation, but there is a lack of evidence to support a specific effect of oats on bowel function compared with other cereals. A long-term dietary intake of oats or oat bran could benefit inflammatory bowel disorders, but this remains to be proven. A protective effect on colorectal adenoma and cancer incidence has not yet been convincingly shown. The majority of patients with coeliac disease could consume up to 100 g/d of uncontaminated oats, which would increase the acceptability of, and adherence to, a gluten-free diet.

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.

Diagnosis and management of adult coeliac disease: guidelines from the British Society of Gastroenterology

A multidisciplinary panel of 18 physicians and 3 non-physicians from eight countries (Sweden, UK, Argentina, Australia, Italy, Finland, Norway and the USA) reviewed the literature on diagnosis and management of adult coeliac disease (CD). This paper presents the recommendations of the British Society of Gastroenterology. Areas of controversies were explored through phone meetings and web surveys. Nine working groups examined the following areas of CD diagnosis and management: classification of CD; genetics and immunology; diagnostics; serology and endoscopy; follow-up; gluten-free diet; refractory CD and malignancies; quality of life; novel treatments; patient support; and screening for CD.

Avena sativa (Oat), a potential neutraceutical and therapeutic agent: an overview

The aim of the present review article is to summarize the available information related to the availability, production, chemical composition, pharmacological activity, and traditional uses of Avena sativa to highlight its potential to contribute to human health. Oats are now cultivated worldwide and form an important dietary staple for the people in number of countries. Several varieties of oats are available. It is a rich source of protein, contains a number of important minerals, lipids, β-glucan, a mixed-linkage polysaccharide, which forms an important part of oat dietary fiber, and also contains various other phytoconstituents like avenanthramides, an indole alkaloid-gramine, flavonoids, flavonolignans, triterpenoid saponins, sterols, and tocols. Traditionally oats have been in use since long and are considered as stimulant, antispasmodic, antitumor, diuretic, and neurotonic. Oat possesses different pharmacological activities like antioxidant, anti-inflammatory, wound healing, immunomodulatory, antidiabetic, anticholesterolaemic, etc. A wide spectrum of biological activities indicates that oat is a potential therapeutic agent.

The safety of oats in the dietary treatment of coeliac disease

Coeliac disease is a permanent inflammatory disorder of the small bowel affecting approximately 1% of the population. The only effective treatment that exists is exclusion of gluten from the diet. The present paper aims to review the literature as to whether oats are safe to eat for people with coeliac disease. Much data exist on the restrictive nature that adhering to a gluten-free diet imposes on an individual. If oats could be eaten, this would help reduce the restrictive nature of the diet. This in turn could lead to an increase in the quality of life. Oats are of high-nutritional value, providing a rich source of fibre, vitamins and minerals. The fibre source contains soluble fibre which is believed to help reduce LDL-cholesterol. A systematic review of the literature was conducted. Earlier studies conducted are difficult to compare as they used different methodologies and it is not known whether samples of oats in the studies were contaminated with gluten from other cereals. Many studies reviewed do not state the strain of oat used. Recent research has suggested that it may only be in certain strains of oats which could produce a toxic response to people with coeliac disease. In conclusion, research suggests that the risk from consuming oats may be less harmful than first thought; however, may vary according to the strain of oat. Handling that risk in clinical practice remains controversial.

Unexplained infertility as primary presentation of celiac disease, a case report and literature review

BACKGROUND

Celiac sprue (gluten sensitive enteropathy) is an autoimmune disease which is hereditary and its pathology mainly bases on immunologic intolerance to gluten. It has a vast variety of signs and symptoms and its clinical features range from a silent disease to a typical gastrointestinal disorder. In this study we reviewed and summarized some other related issues about this disease and its relation with infertility.

CASE

The case is a 26 years old lady who had referred to a gynecologist because of infertility for 2 years and later it revealed that she has celiac sprue.

CONCLUSION

Screening for its silent or subtle types especially among suspicious cases such as unexplained infertility seems to be a cost effective action. Meanwhile, in time administration of a gluten-free diet can lead to an almost complete cure.

Nutrient intakes during diets including unkilned and large amounts of oats in celiac disease

BACKGROUND/OBJECTIVES

We have shown earlier that consumption of moderate amount of oats improve intakes of vitamin B(1), fiber, magnesium and iron in celiac patients using gluten-free diet (GFD). The objective of this study was to clarify the effect of high amount of both kilned and unkilned oats on food and nutrient intakes in celiac patients in remission. Kilning as an industrial heating process is performed to preserve the main properties of oats and to lengthen its useableness. Kilning may, however, change the protein structure of oats and therefore influence on the intake of nutrients.

SUBJECTS/METHODS

The study group consisted of 13 men and 18 women with celiac disease in remission. The patients who were earlier using moderate amount of oats as part of their GFD were randomized to consume kilned or unkilned oats. After 6 months, the patients changed the treatment groups. The goal of daily intake of oats was 100 g. Food records and frequency questionnaire were used to follow nutrient intakes.

RESULTS

Type of oats did not affect the amount of oats used. In the group using kilned oats, the intake of vitamin B1 and magnesium and in the group of unkilned oats that of magnesium and zinc increased significantly during the first 6 months (P<or=0.05).

CONCLUSIONS

:Large amounts of oats, both kilned and unkilned in GFD, can increase intakes of nutrients in celiac patients in remission. Oats improve the nutritional value of GFD.

Introduction of oats in the diet of individuals with celiac disease: a systematic review

Celiac disease is an immune-mediated disease, triggered in genetically susceptible individuals by ingested gluten from wheat, rye, barley, and other closely related cereal grains. The only treatment for celiac disease is a strict gluten-free diet for life. This paper presents a systematic review of the scientific literature on the safety of pure oats for individuals with celiac disease, which historically has been subject to debate. Limitations identified within the scientific database include: limited data on long-term consumption, limited numbers of participants in challenge studies, and limited reporting about the reasons for withdrawals from study protocols. Furthermore, some evidence suggests that a small number of individuals with celiac disease may be intolerant to pure oats and some evidence from in vitro studies suggests that an immunological response to oat avenins can occur in the absence of clinical manifestations of celiac disease as well as suggesting that oat cultivars vary in toxicity. Based on the majority of the evidence provided in the scientific database, and despite the limitations, Health Canada and the Canadian Celiac Association (CCA) concluded that the majority of people with celiac disease can tolerate moderate amounts of pure oats. The incorporation of oats into a gluten-free diet provides high fiber and vitamin B content, increased palatability, and beneficial effects on cardiovascular health. However, it is recommended that individuals with celiac disease should have both initial and long-term assessments by a health professional when introducing pure oats into a gluten-free diet.

Unkilned and large amounts of oats in the coeliac disease diet: a randomized, controlled study

OBJECTIVE

There is evidence for the long-term safety of oats as part of a gluten-free diet in coeliac disease (CD). Oats is generally processed by kilning, which theoretically may change its antigenic properties and be the reason that it is tolerated by patients with CD. The aim of this study was to investigate the suitability of large amounts of unkilned oats, comparing its use with kilned oats in adult coeliac patients.

MATERIAL AND METHODS

The study group included 13 men and 19 women with CD in remission. The goal of daily intake of oats was 100 g during one year. These patients using oats as part of their gluten-free diet were randomized to two treatment groups. One group used regular oats and the other unkilned oats. After 6 months the patients changed the treatment groups. Food intake, symptoms, histology of the small intestine and the levels of endomysial antibodies were noted.

RESULTS

No marked changes were found in the duodenal biopsies, in the levels of endomysial antibodies or in the well-being of the patients. Compliance with the diet did not change during the follow-up.

CONCLUSIONS

Large amounts of both unkilned and regular kilned oats are well tolerated by adult patients with CD. Oats is therefore not harmful, even in its unkilned form, which indicates that its antigenic nature is not changed by common industrial food processing in such a way that would prevent the provoking of CD.

Measurement of wheat gluten and barley hordeins in contaminated oats from Europe, the United States and Canada by Sandwich R5 ELISA

OBJECTIVES

We have investigated the extent of contamination with wheat, barley, rye or a mixture of these cereals in a large number of grains and commercial oats. We have also attempted to identify the type of cereal contaminant.

METHODS

Sandwich R5 ELISA (using either gliadins or hordeins as standards), western blot, matrix-assisted laser desorption/ionization time-of-flight mass spectrometric and quantitative real-time PCR (Q-PCR) techniques have been used to analyze a total of 134 oats, comprising grains and commercial oat products collected from Europe, the United States and Canada.

RESULTS

Twenty-five of the 134 pure, uncontaminated oat varieties were found to have undetectable levels of gluten, whereas most of the 109 grains and commercial oat products were mainly contaminated with mixtures of wheat, barley and rye, barley being the predominant contaminant. The percentages of these cereals in the oat samples have been calculated by specific wheat, barley and rye Q-PCR systems. The oat samples were grouped according to the avenin spectra determined by the mass spectrometric technique. The data confirmed that contaminated oat foods, based on the same variety, could have different levels of wheat, barley and rye contamination.

CONCLUSION

This study has verified that contamination with wheat gliadins or barley hordeins in oat samples can be measured by the Sandwich R5 ELISA, using either gliadins or hordeins as standards, and also the importance of using confirmatory techniques (such as western blot, Q-PCR and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry) to confirm that most oats are contaminated with mixtures of wheat, barley and rye.

No induction of anti-avenin IgA by oats in adult, diet-treated coeliac disease

OBJECTIVE

Coeliac disease is effectively treated with a gluten-free diet devoid of wheat, rye, barley and related cereals. Oats has until recently also been considered harmful but is now allowed in several countries. We have, however, identified three adult coeliac disease patients who developed a flare of active coeliac disease after ingestion of oats, which suggests that oats might not be entirely innocent in coeliac disease. It is known that patients with untreated coeliac disease have elevated IgA antibodies to oat prolamins. The objective of this study was to investigate whether levels of IgA against oats were increased in treated, adult coeliac disease patients.

MATERIAL AND METHODS

Serum was collected from 136 adult patients with treated coeliac disease and 139 controls. Eighty-two of the coeliac disease patients had been taking oats as part of their gluten-free diet for 6 months or more. IgA against oats avenin, wheat gliadin and tissue transglutaminase was tested with ELISA.

RESULTS

No significant differences were found in IgA against oats in oats-eating and non-oats-eating coeliac disease patients. Both groups had increased levels of IgA against wheat, oats and tissue transglutaminase compared to healthy controls. A significant positive correlation was found between anti-avenin and antigliadin IgA (p<0.0001), and between anti-avenin and anti-tissue transglutaminase IgA (p=0.0012).

CONCLUSIONS

Ingestion of oats does not cause increased levels of IgA against oats in adult coeliac disease patients on a gluten-free diet. The findings support the notion that most adult coeliac disease patients can tolerate oats.

Advances in celiac disease and gluten-free diet

Celiac disease is becoming an increasingly recognized autoimmune enteropathy caused by a permanent intolerance to gluten. Once thought to be a rare disease of childhood characterized by diarrhea, celiac disease is actually a multisystemic disorder that occurs as a result of an immune response to ingested gluten in genetically predisposed individuals. Screening studies have revealed that celiac disease is most common in asymptomatic adults in the United States. Although considerable scientific progress has been made in understanding celiac disease and in preventing or curing its manifestations, a strict gluten-free diet is the only treatment for celiac disease to date. Early diagnosis and treatment, together with regular follow-up visits with a dietitian, are necessary to ensure nutritional adequacy and to prevent malnutrition while adhering to the gluten-free diet for life. The purpose of this review is to provide clinicians with current updated information about celiac disease, its diverse clinical presentation and increased prevalence, the complex pathophysiology and strong genetic predisposition to celiac disease, and its diagnosis. This review focuses in detail on the gluten-free diet and the importance of intense expert dietary counseling for all patients with celiac disease. Recent advances in the gluten-free diet include food allergen labeling as well as the US Food and Drug Administration's proposed definition of the food-labeling term gluten-free. The gluten-free diet is complex and patients need comprehensive nutrition education from a skilled dietitian.

Tef in the diet of celiac patients in The Netherlands

OBJECTIVE

Celiac disease (CD) is a multifactorial disease with a strong genetic association. It is caused by a T-cell-mediated immune response to wheat gluten. The treatment is a strict gluten-free diet (GFD). The purpose of this study was to investigate whether the naturally gluten-free cereal Eragrostis tef (tef) is associated with health problems when used by CD patients.

MATERIAL AND METHODS

In March 2006, all 7990 members of the Dutch Celiac Disease Society were invited to complete a questionnaire on tef use and the development of symptoms after tef consumption. Respondents and their family members willing to participate were sent an extended questionnaire on the use of commercially available tef products and on the character of their subsequent symptoms.

RESULTS

Thirty-six percent responded to the first questionnaire of whom 53% consumed tef and 15% reported complaints. For the second questionnaire, out of the 1828 participants willing to complete it, 1545 had biopsy-proven CD (median duration GFD: 6.5 years (range: 0-66.5 years)). Of these, 66% used tef (median duration 1.4 years (range: 0.1-5 years)) and 17% reported symptoms after consumption. The percentage for symptoms was significantly lower than that in patients without tef consumption reporting on their regular GFD (17% versus 61%; p = 0.0001).

CONCLUSIONS

Tef is frequently used by Dutch CD patients and a wide majority can consume tef without experiencing any clinical symptoms. CD patients using tef reported a significant reduction in symptoms, possibly related to a reduction in gluten intake or to an increase in fiber intake. Hence, tef can be a valuable addition to the GFD of CD patients.

Oat: unique among the cereals

This review is intended to focus on the composition of oat and its therapeutic potential in the pharmacology that supports its use to cure various maladies. Oat (Avena sativa) is distinct among the cereals due to its multifunctional characteristics and nutritional profile. Recent advancement in food and nutrition has revealed the importance of its various components. It is a good source of dietary fiber especially beta-glucan, minerals and other nutrients. Oat and oat by products have been proven to be helpful in the treatment of diabetes and cardiovascular disorders. Oat bran in particular, is good source of B complex vitamins, protein, fat, minerals besides heart healthy soluble fiber beta-glucan. The beta-glucan has outstanding functional properties and is of immense importance in human nutrition. Different physiological effects of beta-glucan are related to its viscosity, attenuation of postprandial plasma glucose and insulin responses, high transport of bile acids towards lower parts of the intestinal tract and high excretion of bile acids thereby lowering of serum cholesterol levels. Moreover, it is helpful against coeliac disease. The incorporation of oat grains and oat bran in the food products improves not only the nutrition but also a therapy against various maladies.

Consumption of pure oats by individuals with celiac disease: a position statement by the Canadian Celiac Association

The treatment of celiac disease is a strict adherence to a gluten-free diet for life. In the past, oats were considered to be toxic to individuals with celiac disease and were not allowed in a gluten-free diet. However, recent evidence suggests that oats that are pure and uncontaminated with other gluten-containing grains, if taken in limited quantities, are safe for most individuals with celiac disease. For adults, up to 70 g (1/2 to 3/4 cup) of oats per day and for children, up to 25 g (1/4 cup) per day are safe to consume. These oats and oat products must fulfill the standards for a gluten-free diet set by the Canadian Food Inspection Agency and Health Canada. The Canadian Celiac Association, in consultation with Health Canada, Agriculture & Agri-Food Canada and the Canadian Food Inspection Agency, has established requirements for growing, processing, and purity testing and labelling of pure oats. These strategies have led to the production of pure, uncontaminated oats for the first time in Canada. Oats and oat products that are safe for consumption by individuals with celiac disease and dermatitis herpetiformis are now commercially available in Canada.

Avenins from different cultivars of oats elicit response by coeliac peripheral lymphocytes

OBJECTIVE

The avoidance of oats in coeliac patients is still controversial. If oats is confirmed to be safe, it would be a valuable component and offer more variation in a gluten-free diet. The aim of this work was to evaluate whether avenins from different varieties of oats show different abilities in the activation of coeliac peripheral lymphocytes.

MATERIAL AND METHODS

In order to assess whether the immunogenic effect of oats varies according to the cultivar, peripheral lymphocytes from 10 coeliac children were exposed to avenins from four different oats varieties: Lampton, Astra, Ava and Nave. Lymphocyte proliferation and interferon-gamma (IFN-gamma) release in the culture medium were measured as indexes of immune activation.

RESULTS

All the varieties of oats tested were immunogenic, with Lampton and Ava avenins inducing lymphocyte activation similar to that activated by wheat gliadin, while Astra and Nave avenins showed less immunogenicity, but still with a measurable effect.

CONCLUSIONS

There are still concerns about the suitability of including oats in a gluten-free diet. Coeliac patients consuming oats-containing food should be carefully monitored, until there is more evidence to show the safety of oats and varieties of low-toxicity oats.

Can oats be taken in a gluten-free diet? A systematic review

OBJECTIVE

There has long been doubt about the need to exclude oats from a gluten-free diet (GFD). The objective of this study was to review the literature in order to arrive at a firm recommendation.

MATERIAL AND METHODS

Electronic databases were searched up to February 2006 using the terms "oats" and "coeliac disease".

RESULTS

Twenty relevant studies were found and presented. Early studies were small and uncontrolled and mostly indirect. In 10 studies involving 165 patients, only 1 patient was shown to have histological damage as a result of consuming oats.

CONCLUSIONS

Coeliac patients can, to some advantage, include oats in a GFD although there may be the occasional patient who is also oats sensitive. Previous conflicting results may have been partly due to contamination of oats by wheat. Lest contamination is present and exceeds the safe threshold, we recommend that coeliac patients should only add oats to their GFD when they are established on a conventional GFD, and stop eating oats if they develop any symptoms.

No observed local immunological response at cell level after five years of oats in adult coeliac disease

OBJECTIVE

Our earlier 5-year follow-up study produced the first evidence to show the long-term safety of oats as part of a coeliac diet. The objective of the present study was to clarify its applicability by analysing local cellular immunological responses after 5 years' consumption of oats by adult coeliac patients.

MATERIAL AND METHODS

Forty-two coeliac patients took part in an earlier oats intervention study for 6-12 months. Twenty-two of these patients originally consumed oats as part of their gluten-free diet. During the 5-year follow-up 10 patients had felt uncertain about the safety of long-term consumption of oats and gave up this part of their diet. Finally, 12 of the 22 patients consumed oats for the whole 5-year period. The control group consisted of the remaining 20 coeliac patients using a strict, conventional, gluten-free diet without oats. Intraepithelial CD3, alphabetaTCR (alphabetaIEL) and gammadeltaTCR (gammadeltaIEL) T cells were counted after specific staining of small intestinal biopsy specimens.

RESULTS

There were no differences in the densities of CD3, alphabetaIEL and gammadeltaIEL T cells between the oat and the control groups.

CONCLUSIONS

Long-term use of oats included in the gluten-free diets of patients with coeliac disease does not stimulate an immunological response locally in the mucosa of the small intestine.

Complications of coeliac disease: are all patients at risk?

Coeliac disease is a common condition that is increasingly being recognised as a result of the development of sensitive and specific serology. The diagnosis of coeliac disease and its subsequent treatment with a gluten-free diet have implications for the patient, not just for symptom control but also for the possible effect on quality of life and risk of complications. Whether the mode of presentation of coeliac disease has an effect on survival or risk of complication is yet unclear. This article reviews the available evidence regarding these issues.

Coeliac disease and oats: a systematic review

A systematic review of the literature related to the inclusion of oats in the gluten-free diet for patients with coeliac disease to assess whether oats can be recommended. A computerised literature review of multiple databases was carried out, identifying 17 primary studies, 6 of which met the criteria for inclusion in this review. None of the six studies found any significant difference in the serology between the oats and control groups. Two studies, however, identified a significant difference (p<0.001; p = 0.039) in intraepithelial lymphocyte counts between the oats and control groups. Oats can be symptomatically tolerated by most patients with coeliac disease; however, the long-term effects of a diet containing oats remain unknown. Patients with coeliac disease wishing to consume a diet containing oats should therefore receive regular follow-up, including small bowel biopsy at a specialist clinic for life.

Urinary nitric oxide during one year of gluten-free diet with or without oats in children with coeliac disease

OBJECTIVE

Although in both adults and children with coeliac disease (CD) it is now recommended that oats be added to their gluten-free diet, there is still some controversy concerning the possible harmful effects of oats in some individuals. In this study concentrations of nitric oxide metabolites were repeatedly measured in the urine of children under investigation for CD, when on a gluten-free diet with or without oats.

MATERIAL AND METHODS

The study included 116 children, randomized to a standard gluten-free diet (GFD-std) or a gluten-free diet supplemented with wheat-free oat products (GFD-oats), over a one-year period. Small-bowel biopsy was performed at the beginning and end of the study. Morning urine samples were collected from 87 children and urinary nitrite/nitrate concentrations were monitored at 0, 3, 6, 9 and 12 months.

RESULTS

All patients were in clinical remission after the study period. There was a rapid decline in urinary nitrite/nitrate concentrations in both groups as early as after 3 months. No differences were seen between the study groups at any of the checkpoints. However, at the end of the study, the nitrite/nitrate values of 9 children in the GFD-oats group and 8 children in the GFD-std group had not normalized.

CONCLUSIONS

Children with CD on a gluten-free diet with oats display a similar reduction in urinary nitrite/nitrate as those on a traditional gluten-free diet. Some children, however, still demonstrate high nitrite/nitrate excretion after one year on either diet, indicating that long-term follow-up studies of children on an oats-containing diet are needed.

Oats in the treatment of childhood coeliac disease: a 2-year controlled trial and a long-term clinical follow-up study

BACKGROUND

The exclusion of oats from the diet in coeliac disease is controversial.

AIM

To study the long-term safety of oats in the treatment of children with coeliac disease.

METHODS

Altogether 32 children with coeliac disease were enrolled in a 2-year controlled trial. Twenty-three children in remission were randomized either to oats or gluten challenge; when small bowel histological relapse was evident after gluten challenge, a gluten-free diet including oats was started. Furthermore, nine newly detected coeliac patients adopted an oat-containing gluten-free diet. Small bowel mucosal morphology, CD3+, alphabeta+ and gammadelta+ intraepithelial lymphocytes, human leucocyte antigen (HLA) DR expression and coeliac serology were determined. After the trial, the children were allowed to eat oats freely; follow-up was extended up to 7 years.

RESULTS

In coeliac children in remission, oats had no detrimental effect on intestinal histology or serology during the 2-year trial. In contrast, the gluten-challenge group relapsed after 3-12 months. Complete recovery from the disease was accomplished in all relapsed and newly detected patients on an oat-containing gluten-free diet. After the trial, 86% of the children preferred to consume oats and they all remained in remission.

CONCLUSION

In most children with coeliac disease, long-term consumption of oats is well tolerated, and it does not result in small bowel mucosal deterioration or immune activation.

Immunohistochemical analysis of coeliac mucosa following ingestion of oats

There is now considerable clinical evidence that oats do not activate coeliac disease. Nonetheless, a reluctance to include oats in the gluten-free diet remains. Because gluten-induced damage is accompanied by activation of the gastrointestinal immune system, the purpose of this study was to investigate if similar changes were induced by oats ingestion. Small intestinal histological sections from 10 patients who ingested 50 g of oats daily for 3 months were investigated for possible evidence of immune activation. Tissue obtained before and after oats challenge was stained with a series of antibodies directed against the following molecules: human leucocyte antigen D-related (HLA-DR), Ki-67, CD25, CD54 [intercellular adhesion molecule 1 (ICAM-1)] and mast cell tryptase. None of the patients developed clinical or laboratory evidence of adverse effects. The distribution of intestinal HLA-DR expression was not affected by oats ingestion and the crypt epithelium remained unstained. In the pre-oats biopsies, the percentage of Ki-67 positive enterocytes, 29.5 +/- 6.9 [95% confidence interval (CI) 13.9-45.0] did not differ significantly from that found in post-oats biopsies, 41.2 +/- 3.7 (95% CI, 32.8-49.6), P = 0.19, not significant. Furthermore, oats ingestion did not alter the number of CD25 positive and tryptase positive cells. Finally, the distribution and intensity of ICAM-1 staining was unchanged by dietary oats. In summary, detailed immunohistological studies of biopsies from patients ingesting oats for 3 months did not reveal evidence of immune activation. Together with other reported findings, this study strengthens the view that oats can be included safely in the diet of gluten sensitive patients.

Celiac disease

Celiac disease is a chronic intestinal disease caused by intolerance to gluten. It is characterized by immune-mediated enteropathy, associated with maldigestion and malabsorption of most nutrients and vitamins. In predisposed individuals, the ingestion of gluten-containing food such as wheat and rye induces a flat jejunal mucosa with infiltration of lymphocytes. The main symptoms are: stomach pain, gas, and bloating, diarrhea, weight loss, anemia, edema, bone or joint pain. Prevalence for clinically overt celiac disease varies from 1:270 in Finland to 1:5000 in North America. Since celiac disease can be asymptomatic, most subjects are not diagnosed or they can present with atypical symptoms. Furthermore, severe inflammation of the small bowel can be present without any gastrointestinal symptoms. The diagnosis should be made early since celiac disease causes growth retardation in untreated children and atypical symptoms like infertility or neurological symptoms. Diagnosis requires endoscopy with jejunal biopsy. In addition, tissue-transglutaminase antibodies are important to confirm the diagnosis since there are other diseases which can mimic celiac disease. The exact cause of celiac disease is unknown but is thought to be primarily immune mediated (tissue-transglutaminase autoantigen); often the disease is inherited. Management consists in life long withdrawal of dietary gluten, which leads to significant clinical and histological improvement. However, complete normalization of histology can take years.

Coeliac children on a gluten-free diet with or without oats display equal anti-avenin antibody titres

OBJECTIVE

Recent studies report negligible toxicity of oats in the majority of coeliac disease (CD) patients. It has previously been shown that children with untreated CD have circulating antibodies to oats avenin. In this study we performed serial assessments of anti-avenin antibodies in children under investigation for CD on a gluten-free diet with or without oats.

MATERIAL AND METHODS

The study involved 116 children, randomized to a standard gluten-free diet or a gluten-free diet supplemented with oats. Sera were obtained from 86 children, 48 in the standard gluten-free group and 38 in the gluten-free oats group, of which 33 consumed at least 10 g of oats daily. IgA and IgG anti-avenin antibodies were monitored at 0, 3, 6 and 12 months. Nitric oxide metabolites were measured in 7 patients, with deviating antibody results.

RESULTS

There was a significant decrease in anti-avenin antibodies in both groups at the end as compared to the beginning of the study, (p<0.001), but no difference was found between the two groups. IgA titres already declined after 3 months. IgG titres, although significantly decreased, remained high in the majority of patients in both groups. Nitric oxide levels were high in four of the analysed samples.

CONCLUSIONS

Oats per se, do not seem to produce a humoral immune reaction in children with CD when given in an otherwise gluten-free diet, indicating that the reaction requires gluten challenge. Anti-avenin antibodies were equal in the two study groups, and these findings strengthen the clinical impression that oats can be tolerated by the majority of patients with CD.

Elevated expression of hyaluronan and its CD44 receptor in the duodenal mucosa of coeliac patients

AIMS

Since hyaluronan (HA) metabolism is disturbed in some malignant tumours and in inflammatory diseases, we analysed HA and its receptor CD44 as well as the expression of the Ki67 nuclear protein, a marker of cell proliferation, in histological sections of duodenal biopsies of coeliac disease patients and controls.

METHODS AND RESULTS

The study group consisted of 52 patients with coeliac disease in remission, 40 patients with newly diagnosed disease and 10 healthy control subjects. HA was detected with a specific biotinylated probe prepared from cartilage aggrecan and link protein, and CD44 with an antibody recognizing all forms of CD44 and another specific for its v6 variant. For the expression of the nuclear protein, monoclonal antibody MIB-1 was used. The percentage of HA-positive cells in surface epithelium was higher in newly diagnosed patients (13%) compared with patients in remission (11%) and controls (2%). In addition, HA intensity in the lamina propria was decreased in the newly diagnosed patients. In patients with active disease, 22-26% of the surface epithelium was CD44+, whereas the corresponding figure in patients in remission was 5%, and that of controls 1%. The more intensive MIB-1 labelling in the duodenal epithelium of coeliac patients without treatment was normalized after gluten-free diet.

CONCLUSIONS

The HA-positive coat on surface epithelium seen even in patients in remission suggests persistent or even permanent changes in the epithelial permeability barrier in coeliac disease.

A novel and sensitive method for the detection of T cell stimulatory epitopes of alpha/beta- and gamma-gliadin

BACKGROUND

It is now generally accepted that coeliac disease (CD) is caused by inflammatory T cell responses to gluten peptides bound to HLA-DQ2 or -DQ8 molecules. There is overwhelming evidence that CD patients can mount T cell responses to peptides found in both alpha-gliadin and gamma-gliadin molecules. Assays that would detect the presence or absence of such peptides in food would thus be accurate indicators of safety for consumption by CD patients.

AIMS

The development of a sensitive method to detect T cell stimulatory epitopes of alpha-gliadin and gamma-gliadin molecules in food products.

METHODS

Monoclonal antibodies (mAb) were raised against peptides encoding the T cell stimulatory epitopes of alpha-gliadin (amino acids (aa) 59-71) and aa gamma-gliadin (aa 142-153 and aa 147-159). These mAb competition assays were developed that quantitatively detect T cell stimulatory epitopes present on both intact proteins and peptides of sizes recognisable by CD4(+) T cells.

RESULTS

With the mAb based competition assays, T cell epitopes were detected in pepsin/trypsin digests of wheat proteins and ethanol extracts of various food products, with detection levels lower than those reached with gluten specific T cells. Moreover, the presence of T cell stimulatory epitopes was also detected in preparations of barley, rye, and triticale, other cereals known to be toxic for CD patients.

CONCLUSIONS

A new antibody based method has been developed, detecting the presence of T cell stimulatory gluten peptides. This can be used to further ensure the safety of food consumed by CD patients.

Oats to children with newly diagnosed coeliac disease: a randomised double blind study

BACKGROUND

Treatment of coeliac disease (CD) requires lifelong adherence to a strict gluten free diet (GFD) which hitherto has consisted of a diet free of wheat, rye, barley, and oats. Recent studies, mainly in adults, have shown that oats are non-toxic to CD patients. In children, only open studies comprising a small number of patients have been performed.

AIM

To determine if children with CD tolerate oats in their GFD.

PATIENTS AND METHODS

In this double blind multicentre study involving eight paediatric clinics, 116 children with newly diagnosed CD were randomised to one of two groups: one group was given a standard GFD (GFD-std) and one group was given a GFD with additional wheat free oat products (GFD-oats). The study period was one year. Small bowel biopsy was performed at the beginning and end of the study. Serum IgA antigliadin, antiendomysium, and antitissue transglutaminase antibodies were monitored at 0, 3, 6, and 12 months.

RESULTS

Ninety three patients completed the study. Median (range) daily oat intake in the GFD-oats group (n = 42) was 15 (5-40) g at the six month control and 15 (0-43) g at the end of the study. All patients were in clinical remission after the study period. The GFD-oats and GFD-std groups did not differ significantly at the end of the study regarding coeliac serology markers or small bowel mucosal architecture, including numbers of intraepithelial lymphocytes. Significantly more children in the youngest age group withdrew.

CONCLUSIONS

This is the first randomised double blind study showing that the addition of moderate amounts of oats to a GFD does not prevent clinical or small bowel mucosal healing, or humoral immunological downregulation in coeliac children. This is in accordance with the findings of studies in adult coeliacs and indicates that oats, added to the otherwise GFD, can be accepted and tolerated by the majority of children with CD.

Oats induced villous atrophy in coeliac disease

The current trend is to allow coeliac disease (CD) patients to introduce oats to their gluten free diet. We sought further data from the clinical setting with regards to oats consumption by coeliac patients. Several oat products were tested for wheat contamination using a commercial enzyme linked immunoassay (ELISA) kit, and six samples were examined by an ELISA using a cocktail of monoclonal antibodies, mass spectrometry, and western blot analysis. Nineteen adult CD patients on a gluten free diet were challenged with 50 g of oats per day for 12 weeks. Serological testing and gastroduodenoscopy was performed before and after the challenge. Biopsies were scored histologically and levels of mRNA specific for interferon gamma were determined by reverse transcription-polymerase chain reaction analysis. Oats were well tolerated by most patients but several reported initial abdominal discomfort and bloating. One of the patients developed partial villous atrophy and a rash during the first oats challenge. She subsequently improved on an oats free diet but developed subtotal villous atrophy and dramatic dermatitis during a second challenge. Five of the patients showed positive levels of interferon gamma mRNA after challenge. Some concerns therefore remain with respect to the safety of oats for coeliacs.

Beneficial effects of oats in the gluten-free diet of adults with special reference to nutrient status, symptoms and subjective experiences

In several studies oats have been reported to be tolerated by coeliac patients. The aim of the present study was to investigate the nutritional and symptomatic effects of including oats in the gluten-free diet, as well as the patients' subjective experiences. Twenty adult coeliac patients included large amounts of oats in their diet. Food intake, gastrointestinal symptoms, blood samples and body weight were examined and compared with examination at baseline. Diet compliance was checked monthly. The results are based on fifteen patients eating oats for 2 years plus three with only 6-months consumption. The median daily intake of oats was 93 (range 27-137) g/d, and the compliance was good. The mean intakes of Fe and dietary fibre increased (P<0.001) with the oat diet, as well as the intakes of thiamin and Zn (P<0.02). The bioavailability of Fe tended to decrease; this seems not to have influenced the Fe status. Temporary increased flatulence was experienced the first few weeks, as well as improved bowel function with oats in the diet. All patients who carried out the whole study period wanted to continue eating oats after the study, as they found that addition of oats in the gluten-free diet gave more variation, better taste and satiety. Oats improved the nutritional value of the gluten-free diet, had no negative effects on nutritional status and were appreciated by the subjects. Including oats can help coeliac patients following a strict gluten-free diet.

Oats and the gluten-free diet

Whether oats should be included in a gluten-free diet has been debated for half a century. In 1995, the largest and most scientifically rigorous study on the safety of oats was published. Investigators concluded that the consumption of oats was safe for adults with celiac disease. Since 1995, several additional studies have been published. Without exception, these investigations found no adverse effects associated with the regular consumption of moderate amounts of oats. However, there are concerns among some authorities on celiac disease that even if oats themselves are safe, they nonetheless may be contaminated with wheat, rye, or barley. Unfortunately, the extent to which contamination of commercial oat products occurs is not known. Ideally, if a patient appears likely to use oats, they should be advised to consume only those products tested and found to be free of contamination.

Avenin fails to induce a Th1 response in coeliac tissue following in vitro culture

BACKGROUND

It is well established that the wheat protein gliadin triggers inflammation in coeliac patients. However, the potential toxicity of avenin, the equivalent protein in oats, is debated.

AIM

To investigate the immunogenicity of avenin using the cytokines interferon gamma (IFN-gamma) and interleukin (IL)-2 as markers of immunological activity.

METHODS

Duodenal biopsies from coeliac patients were cultured with 5 mg/ml of peptic tryptic (PT) gliadin (n=9) or 5 mg/ml of PT avenin (n=8) for four hours. Biopsies cultured with RPMI 1640 alone served as controls. Non-coeliac biopsies were also cultured with PT gliadin (n=8) and PT avenin (n=8). Total RNA was extracted from the tissue after culture. Cytokine mRNA was quantified by TaqMan polymerase chain reaction. Secreted cytokine protein was measured in the culture supernatant by enzyme linked immunosorbent assay.

RESULTS

After culture with PT gliadin, an increase in IFN-gamma mRNA was observed in all nine patients with coeliac disease. Increased IFN-gamma protein was also found in four of these patients. Smaller increases in IL-2 mRNA were detected in six subjects with increased IL-2 protein found in two patients. In contrast with PT gliadin, there was no significant IFN-gamma or IL-2 response when coeliac biopsies were cultured with PT avenin. Similarly, biopsies from normal controls did not respond to PT gliadin or PT avenin stimulation.

CONCLUSIONS

The findings of this study suggest that the immunogenic sequences in gliadin are not present in avenin. Moreover, they are in keeping with in vivo studies which report that oats are safe for consumption by coeliac patients.

Adult coeliac patients do tolerate large amounts of oats

OBJECTIVE

The aim of the present study was to investigate whether adult patients with coeliac disease in remission could include large amounts of oats in their daily gluten-free diet for an extended period of time without adverse effects.

DESIGN, SUBJECTS AND METHODS

Twenty adult coeliac patients in remission included large amounts of uncontaminated rolled oats in their daily diet for a prolonged period. The examinations, performed four times during the study period, included small bowel endoscopy with biopsies, blood samples (nutritional status, serological analysis), height and body weight, gastrointestinal symptoms and dietary records. Gastrointestinal symptoms and diet were also investigated through unannounced telephone interviews once a month during the study period.

RESULTS

No adverse effects of a large intake of oats were seen in small bowel histology, serology nor in nutritional status in the 15 subjects who completed the whole study period. Two of the subjects dropped out because of gastrointestinal symptoms and three for non-medical reasons. The median intake of oats was 93 g/day and the compliance to the oat diet was found to be good. Examinations of the patients after drop-out did not show any deterioration in small bowel histology or nutritional status nor raised levels of antibodies.

CONCLUSION

Results from this study indicate that adult patients with coeliac disease in remission can include large amounts of controlled wheat-free rolled oats for an extended period of time without adverse effects.