If you do a search on how much gluten can make you sick, you will be floored at how sensitive we all really are. From what I've read, before your gut has healed even "gluten free" grains will make you sick. Why? Because wheat is everywhere. Crops are rotated on the same field, transported in the same bins, stored and proceesed and packaged in the same facility. Some studies have found that soy is cross contaminated with wheat up to 3,000 PPM (Anderson 2012). Gluten free products must come in under 20 PPM to have the "gluten free" label.
[The FDA] found that for the most sensitive people, intestinal damage begins at 0.4 milligrams of gluten per day (1/200th of a teaspoon of flour or 1/8,750th of that slice of bread), while symptoms begin at 0.015 milligrams of gluten per day (less than 1/500th of a teaspoon of flour or 1/233,333th of that slice of bread). The agency based those conclusions on various studies, including two case studies involving recurrent symptoms in people who consumed communion wafers once each week. (Anderson, 2013)
After your gut has healed, you could probably handle "gluten free" grains...maybe. I'm not an expert (but I do have a Bachelors in Nutritional Science) and I'm just figuring all this out in the past couple of months on my own...the hard way, but I've also spent a lot of time reading online. As of right now, I have non celiac gluten sensitivity, I'm just a couple of months into the gluten-free diet, and I cannot eat "gluten free" grains.