Barley, a member of the grass family, is a major cereal grain grown in temperate climates globally. It was one of the first cultivated grains, particularly in Eurasia as early as 10,000 years ago. Barley has been used as animal fodder, as a source of fermentable material for beer and certain distilled beverages, and as a component of various health foods. It is used in soups and stews, and in barley bread of various cultures. Barley grains are commonly made into malt in a traditional and ancient method of preparation.

In 2016, barley was ranked fourth among grains in quantity produced (141 million tonnes) behind maize, rice and wheat.

Nutrition. In a 100-g serving, raw barley provides 352 Calories and is a rich source (20% or more of the Daily Value, DV) of essential nutrients, including protein, dietary fiber, the B vitamins, niacin (31% DV) and vitamin B6 (20% DV), and several dietary minerals (table). Highest nutrient contents are for manganese (63% DV) and phosphorus (32% DV) (table). Raw barley is 78% carbohydrates, 1% fat, 10% protein, and 10% water (table).

Health implications. According to Health Canada and the US Food and Drug Administration, consuming at least 3 grams per day of barley beta-glucan or 0.75 grams per serving of soluble fiber can lower levels of blood cholesterol, a risk factor for cardiovascular diseases.

Eating whole-grain barley, as well as other grains with lots of fiber, improves regulation of blood sugar (i.e., reduces blood glucose response to a meal). Consuming breakfast cereals containing barley over weeks to months also improved cholesterol levels and glucose regulation.

Like wheat, rye, and their hybrids and derivatives, barley contains gluten, which makes it an unsuitable grain for consumption by people with gluten-related disorders, such as celiac disease, non-celiac gluten sensitivity and wheat allergy sufferers, among others. Nevertheless, some wheat allergy patients can tolerate barley or rye.