Do oats belong in a gluten-free diet?

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.

Application of the rat liver lysosome assay to determining the reduction of toxic gliadin content during breadmaking

Enriched caricain was able to detoxify a major proportion of the gliadin in wholemeal wheat dough by allowing it to react for 5h at 37 °C during the fermentation stage. A reduction of 82% in toxicity, as determined by the rat-liver lysosome assay, was achieved using 0.03% enzyme on weight of dough. Without enzyme, only 26% reduction occurred. The difference in reduction of toxicity achieved is statistically significant (p < 0.01). The results are very similar to those obtained in our previous work using an immuno assay and the same enzyme preparation. They confirm the value of caricain as a means of reducing the toxicity of gliadin and open the way for enzyme therapy as an adjunct to the gluten free diet. This approach should lead to better control over the elimination of dietary gluten intake in conditions such as coeliac disease and dermatitis herpetiformis.

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.

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.

A dietary survey to determine if patients with coeliac disease are meeting current healthy eating guidelines and how their diet compares to that of the British general population

OBJECTIVES

To assess the dietary intake of people with coeliac disease (CD) and to determine if they are meeting the current dietary reference values (DRVs). To compare dietary intakes of people with CD to the dietary intake of the general population. The nutritional contribution of gluten-free products (GFPs) and current purchasing trends was also evaluated.

SUBJECTS/METHODS

106 patients were invited to participate via post. Three-day food diary to assess intake and a short simple questionnaire that looked at purchasing trends of GFP.

RESULTS

Forty-nine patients returned the food diary and 48 returned the questionnaire. Patients were found to have a low intake of energy, non-starch polysaccharides (NSPs), vitamin D and calcium. They were obtaining a significantly lower proportion of energy from fat and a significantly higher proportion of energy from protein than the DRVs (P<0.05). Intake was comparable to the general population for most nutrients, except they had a significantly greater intake of protein, a lower intake of fat and a significantly lower intake of vitamin D (P<0.05). Specialist GFP, especially those obtained on prescription, were an important source of energy, carbohydrate, NSP, calcium and iron.

CONCLUSIONS

Patients with CD are at risk of having an inadequate intake of calcium, NSP and vitamin D. Specialist GFP, which were obtained on prescription, helped patients get a balanced diet and without these patients would be at an increased risk of many deficiencies.

In vitro tests indicate that certain varieties of oats may be harmful to patients with coeliac disease

BACKGROUND

The presence of oats in gluten-free diet is controversial. The aim of this work is to evaluate if different varieties of oats exert different toxicity in coeliac disease.

METHODS

Three varieties of oats were tested by two in vitro assay based on the known ability of peptic-tryptic digests of coeliac-active proteins to agglutinate K562 cells and to disrupt lysosomes, respectively.

RESULTS

Avenins from the Italian variety Astra and the Australian variety Mortlook were much more active than the Australian variety Lampton. Gliadin, digested in the same way, certainly displayed more activity than all three avenins, but rice (var. Roma) did not have measurable activity.

CONCLUSIONS

The results indicate that some varieties of oats may be potentially harmful to individuals with coeliac disease and therefore should be excluded from the gluten-free diet required to maintain good health in coeliac disease. It is important to realize that constant, small amounts of active proteins in the diet, such as certain avenins, may prevent complete recovery of the intestinal mucosa in this disease.

Consumption of gluten-free products: should the threshold value for trace amounts of gluten be at 20, 100 or 200 p.p.m.?

OBJECTIVE

The threshold of gluten contamination in gluten-free products of both dietary and normal consumption is under debate. The objective of this study was to gather information on consumption of gluten-free products intended for dietary use of people under a gluten-free diet. This information is essential to ascertain the exposure of coeliac patients to gluten through their diet and deduce the maximum gluten content that these products should contain to guarantee a safe diet.

METHODS

A diet diary of consumption of gluten-free products intended for dietary use was distributed to the coeliac societies of two typical Mediterranean countries (Italy and Spain) and two Northern countries (Norway and Germany). The diet diary included a self-weigh table of the selected food items and a 10-day consumption table. Results were reported in percentiles as distributions were clearly right skewed.

RESULTS

The respondents included in the study accounted for 1359 in Italy, 273 in Spain, 226 in Norway and 56 in Germany. Gluten-free products intended for dietary use contributed significantly to the diet of coeliac patients in Italy, Germany and Norway and to a lesser degree in Spain. The most consumed gluten-free product in all countries was bread, and it was double consumed in the Northern countries (P<0.001). Mediterranean countries showed consumption of a wider variety of gluten-free foods and pasta was eaten to a large degree in Italy.

CONCLUSIONS

The differences between Northern and Mediterranean countries were not in the total amount of gluten-free products but in the type of products consumed. The observed daily consumption of gluten-free products results in the exposure to rather large amounts of gluten, thus the limit of 200 p.p.m. should be revised. A limit of 20 p.p.m. for products naturally gluten-free and of 100 p.p.m. for products rendered gluten-free is proposed to guarantee a safe diet and to enable coeliac patients to make an informed choice. These limits should be revised as new data become available.

Celiac diet: Its impact on quality of life

The objective of this study was to determine the effects of a gluten-free diet, examining food consumption and limitations on quality of life for those with celiac disease. Twenty-nine items on self-administered questionnaires queried demographics, lifestyle, and food use. Some items were from the Rand Survey (Rand Corporation, Santa Monica, CA). Most responses used three- or five-point Likert scales. They were mailed to members of the Westchester Celiac Sprue Support Group. Of the 274 responses, 253 were usable and were the basis of the compiled results. Seventy-four percent of the respondents were female; 42% were between the ages of 36 and 55 years of age, and 46% were more than 55 years of age. Frequencies and cross-tabulations indicated several areas of negative impact in maintaining a gluten-free diet. They included the difficulties of dining out (86%), travel (82%), and impact on family (67%) and less of a negative impact on career or work (41%). The gluten-free diet impacted various lifestyle aspects of the quality of life for individuals with celiac disease.

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.

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.