Are oats OK on a gluten-free diet?

Apart from issues of contamination during transport, storage and processing, the safety of oats with a gluten-free diet (GFD) has been a topic of debate. A study recently published in GUT, An International Journal of Gastroenterology and Hepatology shows that the immunotoxicity of oats depends on the cultivar (the race or variety selected and maintained intentionally through cultivation). The authors state:

"Coeliac disease (CD) is triggered by an abnormal reaction to gluten. Peptides resulting from partially digested gluten of wheat, barley or rye cause inflammation of the small intestinal mucosa. Previous contradictory studies suggest that oats may trigger the abnormal immunological response in patients with CD. Monoclonal antibodies (moAbs) against the main immunotoxic 33-mer peptide (A1 and G12) react strongly against wheat, barley and rye but have less reactivity against oats. The stated aim of this study is to test whether this observed reactivity could be related to the potential toxicity of oats for patients with CD."

For this study different varieties of oats were selected according to their protein patterns and controlled for purity. They examined differences in moAb (monoclonal antibody) G12 recognition and further determined immunogenicity by 33-mer concentration, T cell proliferation and interferon gamma production. Their findings are fascinating and of great importance to those who are sensitive to gluten:

"Three groups of oat cultivars reacting differently against moAb G12 could be distinguished: a group with considerable affinity, a group showing slight reactivity and a third with no detectable reactivity. The immunogenicity of the three types of oats as well as that of a positive and negative control was determined with isolated peripheral blood mononuclear T cells from patients with CD by measurement of cell proliferation and interferon γ release. A direct correlation of the reactivity with G12 and the immunogenicity of the different prolamins was observed."

In other words, the authors were able to reliably pick out, according to the moAb reaction, an uncontaminated cultivar of oats with a distinct immunotoxic effect that expressed a proliferation of inflammatory white blood cells and cytokines. They also showed that another cultivar had only slight reactivity while the third had none at all. They have demonstrated that (1) oats, depending on the cultivar, can elicit an inflammatory reaction in those with gluten sensitivity, and (2) monoclonal antibodies can be used to distinguish which cultivars are safe.

"The results showed that the reactivity of the moAb G12 is proportional to the potential immunotoxicity of the cereal cultivar. These differences may explain the different clinical responses observed in patients suffering from CD and open up a means to identify immunologically safe oat cultivars, which could be used to enrich a gluten-free diet...This work should also be taken into consideration in food safety regulations, in particular labeling of gluten-free products that may contain oats."

Until labeling for immunologic safety becomes standard practice, unless you know your oats, the only way to be sure of not having a reaction is to not eat them.