I’ve often wondered: are oats gluten free? But a better question is: are oats suitable for people with a gluten intolerance such as Celiac Disease?
Some companies, such as Bob’s Red Mill, now sell “certified gluten free oats”, which implies that they are OK for people with gluten intolerance or sensitivity. And by definition, if oats are certified gluten free, they are gluten free as long as the testing methods are sound.
But there may be another problem for some people. As of now, the definition of gluten only includes the prolamins and glutelins in wheat, rye and barley. So many people believe the only reason oats could contain gluten is if they are contaminated by other grains in the harvesting or milling process. But since many gluten intolerant people, up to 10%, have inflammatory reactions to oats, I wanted to find out more.
I did some research to see if I could find some clues, enlisting the knowledge of Dr. Peter Ray, Stanford Botany Professor Emeritus, whom I’ve had the privilege of knowing for many years. I found out that all of the grains, including rice and corn, which are considered to be gluten free, contain prolamins and glutelins–the categories of proteins that form gluten.
I learned from Peter that oats are Botanically more closely related to the gluten containing grains–wheat, rye, and barley–than they are to the other grains, and actually belong to the same sub-family of the grass family. Rice, corn, millet, and many others belong to other subfamilies, and some belong to a different class of plants altogether (amaranth, buckwheat, and quinoa for example).
This means that oats have inherited more of the same genes as wheat, rye and barley, than the other grains have inherited. (Genes are the body’s instructions for making proteins by linking amino acids together, while proteins are the body’s tools for making things happen inside the body.) So it is possible that oats have proteins that act similarly to gluten in the case of gluten intolerance. Read on for more evidence...
On further research I found information on the website of the Celiac Sprue Association.
They report that the prolamin in oats, called avenin, in fact does contain some of the specific amino acid sequences contained in gluten that trigger the autoimmune response, but in much lower amounts.
“...(especially the amino acid sequences which are in the following orders: Pro-Ser-Gln-Gln and Gln-Gln-Gln-Pro)...
It is important to note that these sequences are NOT found in the proteins of corn and rice.”
These are amino acid sequences of the proteins that cause the immune system to attack the intestinal walls. (see What Is Celiac Disease?)
The CSA has also posted summaries of relevant studies on oats. One of these studies reports that “These peptides have sequences rich in proline and glutamine residues closely resembling wheat gluten epitopes.” (Arentz-Hansen et al, University of Oslo, Norway, 2004)
Another article reports: “Some clear evidence has, however, emerged in the past few years that a small number of gluten-sensitive patients display a specific small intestinal T cell response to oat peptides that cannot be explained by contamination with other cereals.” (Ellis and Ciclitira, European Journal of Gastroenterology & Hepatolagy, 2008.)
Technically, if oats are certified gluten free, they are gluten free. But that is by a definition of gluten that may be misleading.
Since oats have prolamins and glutelins with amino acid sequences that may trigger an autoimmune response in some people, it seems there should perhaps be a new term that alerts people to the fact that oats may be a problem if you are gluten intolerant.
So do your research, and talk to your doctor before including oats in your gluten free diet. You may be fine with them, but it’s best to be sure.