The list of grains that people with celiac disease must avoid includes not only wheat but also rye and barley.
Scientists studying cereal grains are doing a lot of research to try and find more safe food for people with celiac disease to eat, because the demand for other options is so great. There are other grains that are safe. However, the question of whether or not oats are safe for people with CD to eat has been hard to answer definitively.
There are people who have reported symptoms when they eat oats. Is this because the proteins in oats are close enough in structure to the gliadins in wheat gluten, or is it because oats are frequently processed in ways that lead to cross contamination of oats with other grains? A related question is – are there species of oats that are different enough that some are dangerous to people with celiac disease while others are not?
When tested, there have been two peptides, or pieces of protein from oats called avenins that might be recognized as “T cell epitopes” in patients with celiac disease. It has been suggested that some oats may have these avenins while others do not, leading to the difference in tolerance between different oats.
One group of researchers looked at 14 different oat (also called Avena) species to see if they all contained the avenins recognized by T cells from affected people, or if these protein pieces really different from one oat type to another.
Each oat plant had as many as 10 avenin genes. The proteins themselves were found in four clusters, and two of these had the specific avenins recognized by T cells from people with CD. Every single oat species studied had these two avenins. The researchers concluded that it would be extremely doubtful that any oat variety is free of these protein pieces, which means that any difference in reaction to oats is not because some are free of related proteins while others are not.
However, further analysis showed that the suspicious avenins are not close enough to the pieces of gluten to actually trigger reactions in patients with celiac disease. Cloning all of the genes allowed them and the proteins they tell the body to make to be closely studied. None of these protein pieces are the same as those in wheat, barley and rye; they are not what are called “gluten epitopes.” Also, they are all almost certainly digested by enzymes in the gastrointestinal tract, and unlikely to arrive at the small intestine intact. Even if they did, the difference between these and the pieces of protein from wheat, barley and rye are great enough to conclude that they will not cause celiac disease reactions or symptoms.
The scientists therefore concluded, after studying all the proteins and pieces, that there are no oat species dangerous to people with CD.
This is important because oats are extremely nutritious as compared with other tolerated grains. They contain soluble fiber of high quality, which is missing in a gluten-free diet without oats.
The research was done by scientists from Wageningen UR in the Netherlands. This company as well as other companies is making products using oats that are free of gluten contamination during processing. Breads and breakfast foods are already available, with more on the way.