The design of these trials are terrible. The wash-out periods are too short, the symptoms they are recording too limited (not all food allergies/intolerances/celiac manifest with gut symptoms, for me it's mostly cognitive for example), and not least are the food they provide in order for it to be blinded for the participants often full of other ingredients that may be difficult to digest and that could give symptoms as well.
With oats in particular, there is a protein similar to gluten that some may react to. I get similar symptoms to eating gluten if I eat (certified gluten free) oats for an extended period of time, I don't know what I'm reacting to. The food could also have some protective factor, using oats again they have beneficial fibers which could be protective by changing the microbiome in a beneficial way.
For gluten free pasta I can recommend red lentil pasta
With oats in particular, there is a protein similar to gluten that some may react to. I get similar symptoms to eating gluten if I eat (certified gluten free) oats for an extended period of time, I don't know what I'm reacting to. The food could also have some protective factor, using oats again they have beneficial fibers which could be protective by changing the microbiome in a beneficial way.
For gluten free pasta I can recommend red lentil pasta