Grains are grasses that are farmed for the edible part of the plant which is composed of three parts. They are the endosperm, the germ and the bran. They are staple crops in North America and are a rich source of vitamins, minerals, carbohydrates, fats and oils.
Refining processes, however, often remove the more nutritious and beneficial bran and germ. Despite the relatively innutritious form grains, in the form of rice and maize are not only staples but frequently the majority of daily sustenance available.
Maize is the most widely produced grain with over 792 million tonnes harvested worldwide in 2007 with rice running a close second at 659 million tons.