Another substance found in common plant food with low-level toxicity is oxalate — it is found in bran, beets, soy, blueberries, lime peel, orange peel, nuts, and several other things.
It does contain some whole grains but remember that wheat bran is not a whole grain because the bran is just one part of the grain even though it does offer nutrition.
When that husk removal is done, what's left is the oat's groat—which is its entire bran, endosperm and germ, the three components that constitute a whole grain.