Herbs & Supplements

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Uses

For medical use, whole barley seeds--along with cereals, flour, oil, and other products made from them--are being investigated for treating diabetes, high cholesterol, and obesity. Some evidence from separate studies involving laboratory animals and humans suggests that barley seed products in the diet may improve blood sugar levels in individuals with diabetes--possibly because the fiber in barley seeds delays stomach emptying and slows down the absorption of carbohydrates from foods. Barley fiber does not appear to affect blood sugar for individuals who do not have diabetes, though.

Like oatmeal, barley seeds contain two kinds of fiber--some that dissolves in water (known as beta-glucan) and some that does not dissolve. Both types of barley fiber may help to lower cholesterol. In clinical studies, many participants who ate barley or bakery made with barley showed reductions in their blood levels of total cholesterol, low-density lipoprotein (LDL, the "bad" cholesterol), or triglyceride as compared to participants who ate products made with wheat flour. Several possible effects are believed to be involved. Beta-glucan in the barley products may keep fat from being absorbed from food, it may speed up the breakdown of cholesterol by the body, and it may force the body to use larger amounts of cholesterol to make bile. The positive results from some studies were unpredictable, however, with some participants showing no difference in cholesterol levels while others on the same diet had significant reductions. Nonetheless, in 2006, the U.S. Food and Drug Administration (FDA) began allowing manufacturers of barley foods to make health claims on the labels. Foods that provide at least 3 grams of beta-glucan per day can be promoted as effective in lowering LDL and total cholesterol levels.

Oil extracted from barley seeds may help to control blood cholesterol levels, as well, but only if it replaces animal fats. Fats generally are classified as saturated or unsaturated according to their chemical structures. Saturated fats usually are solid at room temperature. Mainly derived from animal sources, saturated fats are more likely to form deposits (plaques) in blood vessels, thereby increasing the chance of having high cholesterol and heart disease. Liquid plant oils such as barley oil, are mostly unsaturated. They contain fatty acids that are thought to block the production of chemicals that lead to the formation of deposits in the blood vessels. When unsaturated (plant) fats replace saturated (animal) fats in the diet, blood cholesterol levels may be lowered and the risk of heart disease may decrease.

Both barley seed and barley oil contain calories that can contribute to weight gain. However, barley seed fiber actually may help individuals lose weight by creating a feeling of fullness that lasts because the fiber swells causing stomach contents to stay in the stomach longer. Barley seeds may also protect against colon cancer. Generally, the fiber in barley seeds has been shown to help prevent colon cancer in laboratory animals. Further studies are needed to prove all of these possible uses for barley, however.

After beer is brewed, the leftover barley (commonly known as brewer's spent grain) may be used for animal feed. It may also be allowed to sprout, producing a product called germinated barley foodstuff (GBF), which contains more protein than unsprouted barley. GBF also has high amounts of insoluble fiber. In several studies of humans, GBF has helped to relieve diarrhea, inflammation, pain, and other symptoms associated with gastrointestinal (GI) conditions such as ulcerative colitis. In laboratory animals, GBF helped to reduce chemical damage to the lining of the colon.

Usually called barley grass, the leaves and leaf juice of the barley plant also appear to lower blood cholesterol levels. A small study conducted in China showed that taking barley grass decreased LDL for patients with type 2 diabetes. In addition, chemicals in barley grass may delay or prevent the development of blood vessel damage that can be caused by diabetes. Barley grass also contains large amounts of beta carotene, folic acid, calcium, and several B vitamins--making it a good source of nutrients. Barley grass is often combined with alfalfa, spirulina, or other grain shoots, such as oat grass and wheat grass to make products that are advertised as "total nutrition" or "green" foods.