Oat Fiber: What It Is and Why It Is Not the Same as Oat Bran or Oat Flour
The oat fiber listed in high-fiber foods is commonly oat-hull fiber rather than oat flour or bran. FDA describes oat hull fiber as isolated from the outer hull removed from the edible oat groat and generally containing at least about 85% nondigestible carbohydrate, mostly insoluble cellulose and hemicellulose. This makes it very different from bran or flour, which still contain substantial starch, protein, and beta-glucan.