Grains are staple foods in most societies. In traditional diets, grain were typically consumed either in whole intact form or as coarse flours produced from stone grinding.
Grinding or milling using modern technology produces fine flours with very small particle size. Milling also removes most of the bran and much of the germ. The resulting refined grain products contain more starch but lose substantial amount of dietary fiber, vitamins, minerals, essential fatty acids, and phytochemicals. Because of loss of the outer bran layer and pulverization of the endosperm, refined grains are digested and absorbed more rapidly than whole grain products and tend to cause more rapid and larger increases in levels of blood glucose and insulin. Thus, whole grain products such as whole wheat breads, brown rice, oats, and barley usually have lower glycemic index
(GI) values than refined grains. Whole grains are also rich in fiber, antioxidant vitamins, magnesium, and phytochemicals.
Grinding or milling using modern technology produces fine flours with very small particle size. Milling also removes most of the bran and much of the germ. The resulting refined grain products contain more starch but lose substantial amount of dietary fiber, vitamins, minerals, essential fatty acids, and phytochemicals. Because of loss of the outer bran layer and pulverization of the endosperm, refined grains are digested and absorbed more rapidly than whole grain products and tend to cause more rapid and larger increases in levels of blood glucose and insulin. Thus, whole grain products such as whole wheat breads, brown rice, oats, and barley usually have lower glycemic index
(GI) values than refined grains. Whole grains are also rich in fiber, antioxidant vitamins, magnesium, and phytochemicals.
