Whole Grains, Refined Grains, Enriched Grains: what’s the difference?

Info source: http://health.gov/dietaryguidelines/dga2010/dietaryguidelines2010.pdf

whole grains
include the entire grain seed,
usually called the kernel. The kernel consists
of three components—the bran, germ, and
endosperm. If the kernel has been cracked,
crushed, or flaked, then, to be called a “whole
grain” a food must retain the same relative
proportions of these components as they exist
in the intact grain. Whole grains are con-
sumed either as a single food (e.g., wild rice or
popcorn) or as an ingredient in foods (e.g., in
cereals, breads, and crackers). Some examples
of whole-grain ingredients include buckwheat,
bulgur, millet, oatmeal, quinoa, rolled oats,
brown or wild rice, whole-grain barley, whole
rye, and whole wheat.

refined grains
have been milled to remove the
bran and germ from the grain. This is done to
give grains a finer texture and improve their
shelf life, but it also removes dietary fiber, iron,
and many B vitamins.

enriched grains
are grain products with B
vitamins (thiamin, riboflavin, niacin, folic acid)
and iron added. Most refined-grain products
are enriched.