Barley is a major cereal grain used for both food (bread) and drink (beer); it contains eight essential amino acids. According to a recent study, eating whole grain barley can regulate blood sugar (i.e. reduce blood glucose response to a meal) for up to 10 hours after consumption compared to white or even whole-grain wheat, which has a similar glycemic index. The effect was attributed to colonic fermentation of indigestible carbohydrates. Barley can also be used as a coffee substitute.
Hulled barley (or covered barley) is eaten after removing the inedible, fibrous outer hull. Once removed, it is called dehulled barley (or pot barley or scotch barley). Considered a whole grain, dehulled barley still has its bran and germ making it a nutritious and popular health food. Pearl barley (or pearled barley) is dehulled barley which has been steam processed further to remove the bran. It may be polished, a process known as "pearling". Dehulled or pearl barley may be processed into a variety of barley products, including flour, flakes similar to oatmeal, and grits.