Super quick grain anatomy lesson: u003ca href=u0022https://wholegrainscouncil.org/what-whole-grainu0022 target=u0022_blanku0022 rel=u0022noreferrer noopeneru0022u003eall whole grains have three partsu003c/au003e, the bran, the germ, and the endosperm. If you took a whole grain and ground it up you'd have whole grain flour. If you stripped away the bran and the germ and ground up only the endosperm you'd have white flour.u003cbr/u003eu003cbr/u003eWheat bran or oat bran is simply the bran part of the grain. It's the toughest part of the grain, the outer layer which protects the germ and the endosperm. It's hella high in dietary fiber, which makes your colon a happy camper.