Adding oats to increase the nutritional value of a gluten-free diet does not appear to affect symptoms, histology, immunity or serologic features of patients with celiac disease, according to new research published in Gastroenterology.
These results are “reassuring, and suggest that non-contaminated oats are tolerated by the great majority of patients,” Peter H. R. Green, MD, professor of medicine at Columbia University Medical Center, and director of the Celiac Disease Center at Columbia University, and colleagues wrote. However, they noted that their “confidence is limited by the low quality and limited geographic distribution of the data.”
Peter H. R. Green
“We found no evidence that addition of oats to a [gluten-free diet] affects symptoms or activates celiac disease,” María Inés Pinto-Sánchez, MD, MSc, and Elena F. Verdú, MD, PhD, both of the Farncombe Family Digestive Research Institute at McMaster University, Ontario, Canada, told Healio Gastroenterology via email. “However, we should take into consideration that there were few studies in some of the analyses, most of them were conducted in Europe, and the quality of the evidence was graded as low. The study highlights the need of more rigorous trials from different regions of the world, as the purity of oats will depend on the country of origin and local regulations. Until then, we endorse the recommendations by the North American Society for the Study of Celiac Disease (NASSCD) to support the use of pure oats in [celiac disease], but to monitor levels of tTGA before and after their introduction into the diet.”
Pure oats avoid gluten contamination in their production and are generally considered safe for patients with celiac disease, whereas traditional commercial oats are often contaminated, according to the researchers.
However, some studies have suggested oats themselves may be harmful, while later studies have concluded otherwise, they noted.
“The protein fractions considered to be the constituents of most concern in celiac patients include the alcohol-soluble fractions (prolamins) of wheat (gliadins), rye (secalins) and barley (hordeins),” the researchers wrote. “The prolamine fraction in oats (avenins) is structurally different from other prolamin fractions, and represents only a small proportion of total oats protein.”
María Inés Pinto-Sánchez
Elena F. Verdú
To better address the controversies surrounding the safety of adding oats to a gluten-free diet, Green and colleagues reviewed studies evaluating the safety of oats as part of a gluten-free diet in patients diagnosed with celiac disease or the related skin condition dermatitis herpetiformis. They ultimately included 28 studies published up to January 2017 in their analysis, six of which were randomized controlled trials that used pure uncontaminated oats, and two of which were non-randomized controlled trials (RCTs, n = 661), while the rest were observational studies. Only RCT data were included in a meta-analysis.
One year of eating oats showed no significant effects on symptoms, histologic findings, intraepithelial lymphocyte counts, or serologic test results. These findings were comparable in both adults and children.
Further, the results of three non-RCTs suggested that dermatitis herpetiformis lesions did not worsen after consumption of oats. No studies compared regular vs. pure oats.
The investigators noted that all available RCTs were conducted in Europe, and because the purity of oats depends on the country of origin and its regulations, there is an “urgent need for studies in North America and other regions of the world where [celiac disease] is prevalent. Results from studies in Europe using locally sourced oats cannot be extrapolated to North America.”
They concluded that available data suggest celiac patients can safely consume non-contaminated oats, but more rigorous data are needed. – by Adam Leitenberger
Disclosures: The researchers report no relevant financial disclosures.
Editor's Note: This article was updated on April 25 with additional comments from the study investigators.