Gluten contamination in the Canadian commercial oat supply

Advances in diagnosis and management of celiac disease

Celiac disease is an autoimmune disorder that is induced by dietary gluten in genetically predisposed individuals. It has a prevalence of approximately 1% in many populations worldwide. New diagnoses have increased substantially, owing to increased awareness, better diagnostic tools, and probable real increases in incidence. The breadth of recognized clinical presentations continues to expand, making the disorder highly relevant to all physicians. Newer diagnostic tools, including serologic tests for antibodies against tissue transglutaminase and deamidated gliadin peptide, greatly facilitate diagnosis. Tests for celiac-permissive HLA-DQ2 and HLA-DQ8 molecules are useful in defined clinical situations. Celiac disease is diagnosed by histopathologic examination of duodenal biopsy specimens. However, according to recent controversial guidelines, a diagnosis can be made without a biopsy in certain circumstances, especially in children. Symptoms, mortality, and risk for malignancy each can be reduced by adherence to a gluten-free diet. This treatment is a challenge, however, because the diet is expensive, socially isolating, and not always effective in controlling symptoms or intestinal damage. Hence, there is increasing interest in developing nondietary therapies.

Living gluten-free: adherence, knowledge, lifestyle adaptations and feelings towards a gluten-free diet

BACKGROUND

A gluten-free diet (GFD) requires tremendous dedication, involving substantive changes to diet and lifestyle that may have a significant impact upon quality of life. The present study aimed io assess dietary adherence, knowledge of a GFD, and the emotional and lifestyle impact of a GFD.

METHODS

Community dwelling adults following a GFD completed a questionnaire with items related to reasons for avoiding gluten, diagnostic testing, GFD adherence, knowledge and sources of information about a GFD, the Work and Social Adjustment Scale, and the effect of a GFD diet on lifestyle, feelings and behaviours.

RESULTS

Strict GFD adherence among the 222 coeliac disease (CD) patients was 56%. Non-CD individuals (n = 38) were more likely to intentionally ingest gluten (odds ratio = 3.7; 95% confidence interval = 1.4-9.4). The adverse impact of a GFD was modest but most pronounced in the social domain. Eating shifted from the public to the domestic sphere and there were feelings of social isolation. Affective responses reflected resilience because acceptance and relief were experienced more commonly than anxiety or anger. Non-CD respondents were less knowledgeable and less likely to consult health professionals. They experienced less anger and depression and greater pleasure in eating than CD respondents.

CONCLUSIONS

The findings obtained in the present suggest there is good potential for positive adaptation to the demands of a GFD; nevertheless, there is a measurable degree of social impairment that merits further study. The GFD may be a viable treatment option for conditions other than CD; however, education strategies regarding the need for diagnostic testing to exclude CD are required.

The gluten-free diet and its current application in coeliac disease and dermatitis herpetiformis

BACKGROUND

A gluten-free diet (GFD) is currently the only available therapy for coeliac disease (CD).

OBJECTIVES

We aim to review the literature on the GFD, the gluten content in naturally gluten-free (GF) and commercially available GF food, standards and legislation concerning the gluten content of foods, and the vitamins and mineral content of a GFD.

METHODS

We carried out a PubMed search for the following terms: Gluten, GFD and food, education, vitamins, minerals, calcium, Codex wheat starch and oats. Relevant papers were reviewed and for each topic a consensus among the authors was obtained.

CONCLUSION

Patients with CD should avoid gluten and maintain a balanced diet to ensure an adequate intake of nutrients, vitamins, fibre and calcium. A GFD improves symptoms in most patients with CD. The practicalities of this however, are difficult, as (i) many processed foods are contaminated with gluten, (ii) staple GF foods are not widely available, and (iii) the GF substitutes are often expensive. Furthermore, (iv) the restrictions of the diet may adversely affect social interactions and quality of life. The inclusion of oats and wheat starch in the diet remains controversial.

Practical approach to implementing dietary therapy in adults with eosinophilic esophagitis: the Chicago experience

Eosinophilic esophagitis (EoE) is a chronic immune/antigen-mediated esophageal disease characterized by esophageal dysfunction and esophageal mucosal eosinophilia. Diet therapy is effective in the treatment of EoE in both children and adults. The role of food allergens is well established in the pathogenesis and treatment of eosinophilic esophagitis. Empiric elimination with a six-food elimination diet (avoiding milk, wheat, egg, soy, peanuts/tree nuts, and fish/shellfish) demonstrates remission in over 70% of adults with this disease. Dietary therapy in adult EoE is becoming more accepted by both patients and clinicians. Dietary therapy can be effectively implemented in clinical practice with appropriate dietary education, patient resources, and close communication with physician and clinical staff. The ability to identify specific food triggers to help tailor dietary therapy for long-term management allows for a return to consumption of most table foods. Furthermore, the diet approach avoids the need for chronic topical corticosteroid use and possible long-term side effects of these medications. The decision to proceed with dietary therapy should be decided by patient preference and available resources. A collaborative and multidisciplinary approach including gastroenterologists, allergists, nurses, and dietitians is essential in the success of this approach.

Gluten contamination in foods labeled as "gluten free" in the United States

Gluten is the main storage protein in grains and consists of gliadin and glutenin occurring in the same ratio. Persons suffering from intolerances, including celiac disease, must avoid foods containing gluten or products containing wheat, barley, and rye. Accordingly, gluten detection is of high interest for the food safety of celiac patients. This study was designed to determine the concentrations of gluten in foods labeled "gluten free" available in the United States. Seventy-eight samples labeled gluten free were collected and analyzed using a gliadin competitive enzyme-linked immunosorbent assay. The gluten content was calculated based on the assumption of the same ratio between gliadin and glutenin. Forty-eight (61.5%) of the 78 samples contained less than the limit of quantification of 10 mg/kg for gluten. In addition, 14 (17.9%) of the 78 samples labeled gluten free contained less gluten than the guidelines established by the Codex Alimentarius for gluten-free labeling (20 mg/kg). However, 16 samples (20.5%) did contain gluten levels of ≥20 mg/kg, ranging from 20.3 to 60.3 mg/kg. In particular, five of eight breakfast cereal samples showed gluten contents higher than 20 mg/kg. These results may be of concern, as gluten sensitivity is known to vary among celiac disease patients.

Characterization of grain-specific peptide markers for the detection of gluten by mass spectrometry

Global and targeted mass spectrometry-based proteomic approaches were developed to discover, evaluate, and apply gluten peptide markers to detect low parts per million (ppm) wheat contamination of oats. Prolamins were extracted from wheat, barley, rye, and oat flours and then reduced, alkylated, and digested with chymotrypsin. The resulting peptides were subjected to LC-MS/MS analysis and database matching. No peptide markers common to wheat, barley, and rye were identified that could be used for global gluten detection. However, many grain-specific peptide markers were identified, and a set of these markers was selected for gluten detection and grain differentiation. Wheat flour was spiked into gluten-free oat flour at concentrations of 1-100,000 ppm and analyzed to determine the lowest concentration at which the wheat "contaminant" could be confidently detected in the mixture. The same 2D ion trap instrument that was used for the global proteomics approach was used for the targeted proteomics approach, providing a seamless transition from target discovery to application. A powerful, targeted MS/MS method enabled detection of two wheat peptide markers at the 10 ppm wheat flour-in-oat flour concentration. Because gluten comprises approximately 10% of wheat flour protein, the reported wheat gluten-specific peptides can enable detection of approximately 1 ppm of wheat gluten in oats.

Soy in wheat--contamination levels and food allergy risk assessment

In the United States, packaged food ingredients derived from allergenic sources must be clearly labeled. However, no requirement exists to declare the presence of residues of raw agricultural commodities due to agricultural commodity comingling. Clinical reports of allergic reactions to undeclared soy in wheat-based products do not exist suggesting that a rather low degree of risk is posed by wheat-based products that are comingled with soy. Detectable soybean residues (>2.5 ppm soy flour) were found in 62.8% of commercially available wheat flours at concentrations of 3-443 ppm soy flour (1.6-236 ppm soy protein). Conservative probabilistic risk assessments predict a risk of allergic reaction among the most sensitive soy-allergic individuals of 2.8±2.0 per 1000 soy-allergic user eating occasions of foods containing wheat flour. However, the predicted reactions occur at exposure levels below the lowest eliciting dose observed to provoke objective reactions in clinical oral soy challenges. Given this low level of predicted risk and the lack of evidence for allergic reactions among soy-allergic consumers to wheat-based products, the avoidance of wheat-based products by soy-allergic consumers does not appear to be necessary.

Long-term consumption of oats in adult celiac disease patients

Many celiac disease patients tolerate oats, but limited data are available on its long-term consumption. This was evaluated in the present study, focusing on small-bowel mucosal histology and gastrointestinal symptoms in celiac adults maintaining a strict gluten-free diet with or without oats. Altogether 106 long-term treated celiac adults were enrolled for this cross-sectional follow-up study. Daily consumption of oats and fiber was assessed, and small-bowel mucosal morphology and densities of CD3+, αβ+ and γσ+ intraepithelial lymphocytes determined. Gastrointestinal symptoms were assessed by a validated Gastrointestinal Symptom Rating Scale questionnaire. Seventy (66%) out of the 106 treated celiac disease patients had consumed a median of 20 g of oats (range 1–100 g) per day for up to eight years; all consumed oat products bought from general stores. Daily intake and long-term consumption of oats did not result in small-bowel mucosal villous damage, inflammation, or gastrointestinal symptoms. Oat-consumers had a significantly higher daily intake of fiber than those who did not use oats. Two thirds of celiac disease patients preferred to use oats in their daily diet. Even long-term ingestion of oats had no harmful effects.

Accuracy of ELISA detection methods for gluten and reference materials: a realistic assessment

The determination of prolamins by ELISA and subsequent conversion of the resulting concentration to gluten content in food appears to be a comparatively simple and straightforward process with which many laboratories have years-long experience. At the end of the process, a value of gluten, expressed in mg/kg or ppm, is obtained. This value often is the basis for the decision if a product can be labeled gluten-free or not. On the basis of currently available scientific information, the accuracy of the obtained values with commonly used commercial ELISA kits has to be questioned. Although recently several multilaboratory studies have been conducted in an attempt to emphasize and ensure the accuracy of the results, data suggest that it was the precision of these assays, not the accuracy, that was confirmed because some of the underlying assumptions for calculating the gluten content lack scientific data support as well as appropriate reference materials for comparison. This paper discusses the issues of gluten determination and quantification with respect to antibody specificity, extraction procedures, reference materials, and their commutability.

ACG clinical guidelines: diagnosis and management of celiac disease

This guideline presents recommendations for the diagnosis and management of patients with celiac disease. Celiac disease is an immune-based reaction to dietary gluten (storage protein for wheat, barley, and rye) that primarily affects the small intestine in those with a genetic predisposition and resolves with exclusion of gluten from the diet. There has been a substantial increase in the prevalence of celiac disease over the last 50 years and an increase in the rate of diagnosis in the last 10 years. Celiac disease can present with many symptoms, including typical gastrointestinal symptoms (e.g., diarrhea, steatorrhea, weight loss, bloating, flatulence, abdominal pain) and also non-gastrointestinal abnormalities (e.g., abnormal liver function tests, iron deficiency anemia, bone disease, skin disorders, and many other protean manifestations). Indeed, many individuals with celiac disease may have no symptoms at all. Celiac disease is usually detected by serologic testing of celiac-specific antibodies. The diagnosis is confirmed by duodenal mucosal biopsies. Both serology and biopsy should be performed on a gluten-containing diet. The treatment for celiac disease is primarily a gluten-free diet (GFD), which requires significant patient education, motivation, and follow-up. Non-responsive celiac disease occurs frequently, particularly in those diagnosed in adulthood. Persistent or recurring symptoms should lead to a review of the patient's original diagnosis to exclude alternative diagnoses, a review of the GFD to ensure there is no obvious gluten contamination, and serologic testing to confirm adherence with the GFD. In addition, evaluation for disorders associated with celiac disease that could cause persistent symptoms, such as microscopic colitis, pancreatic exocrine dysfunction, and complications of celiac disease, such as enteropathy-associated lymphoma or refractory celiac disease, should be entertained. Newer therapeutic modalities are being studied in clinical trials, but are not yet approved for use in practice. Given the incomplete response of many patients to a GFD-free diet as well as the difficulty of adherence to the GFD over the long term, development of new effective therapies for symptom control and reversal of inflammation and organ damage are needed. The prevalence of celiac disease is increasing worldwide and many patients with celiac disease remain undiagnosed, highlighting the need for improved strategies in the future for the optimal detection of patients.

Nutrition assessment in celiac disease

The gluten-free diet is currently the only treatment for celiac disease, and patients should be monitored closely by a dietitian who is knowledgeable regarding this diet. Evaluation by a dietitian includes a comprehensive assessment of dietary history, with an emphasis on caloric and micronutrient intake. Patient knowledge of the gluten-free diet is assessed and interpretation of food labels is taught. Identification of micronutrient deficiencies or comorbid gastrointestinal conditions may occur during a comprehensive dietary assessment. In patients with evidence of gluten exposure, a thorough evaluation for cross-contamination is performed.

Patients with celiac disease are not followed up adequately

BACKGROUND & AIMS

Adherence to a gluten-free diet is the only effective treatment for celiac disease. It has been recommended that patients be followed up, make regular visits to the clinic, and undergo serologic analysis for markers of celiac disease, although a follow-up procedure has not been standardized. We determined how many patients with celiac disease are actually followed up.

METHODS

We collected data on 122 patients with biopsy-proven celiac disease, diagnosed between 1996 and 2006 in Olmsted County, Minnesota (70% women; median age, 42 y), for whom complete medical records and verification of residency were available. We determined the frequency at which patients received follow-up examinations, from 6 months to 5 years after diagnosis. The Kaplan-Meier method was used to estimate event rates at 1 and 5 years. Patients were classified according to categories of follow-up procedures recommended by the American Gastroenterological Association (AGA).

RESULTS

We estimated that by 1 and 5 years after diagnosis with celiac disease, 41.0% and 88.7% of the patients had follow-up visits, 33.6% and 79.8% were assessed for compliance with a gluten-free diet, 3.3% and 15.8% met with a registered dietitian, 2.5% and 18.1% had an additional intestinal biopsy, and 22.1% and 65.6% received serologic testing for markers of celiac disease, respectively. Among 113 patients (93%) who were followed up for more than 4 years, only 35% received follow-up analyses that were consistent with AGA recommendations.

CONCLUSIONS

Patients with celiac disease are not followed up consistently. Follow-up examinations often are inadequate and do not follow AGA recommendations. Improving follow-up strategies for patients with celiac disease could improve management of this disease.

Food production and processing considerations of allergenic food ingredients: a review

Although most consumers show no adverse symptoms to food allergens, health consequences for sensitized individuals can be very serious. As a result, the Codex General Standard for the Labelling of Prepackaged Foods has specified a series of allergenic ingredients/substances requiring mandatory declaration when present in processed prepackaged food products. Countries adhering to international standards are required to observe this minimum of eight substances, but additional priority allergens are included in the list in some countries. Enforcement agencies have traditionally focused their effort on surveillance of prepackaged goods, but there is a growing need to apply a bottom-up approach to allergen risk management in food manufacturing starting from primary food processing operations in order to minimize the possibility of allergen contamination in finished products. The present paper aims to review food production considerations that impact allergen risk management, and it is directed mainly to food manufacturers and policy makers. Furthermore, a series of food ingredients and the allergenic fractions identified from them, as well as the current methodology used for detection of these allergenic foods, is provided.