Barley also known as Hordeum vulgare, green grass, mai ya in Chinese markets. The term mai ya could refer to either barley or wheat grass, but barley is preferred to wheat in traditional Chinese medicine. Gu ya, or rice shoots, are eaten as a food rather than taken as a medicine. Barley grass has been used in traditional Chinese medicine for at least 1800 years. Barley grass is grown by soaking the seeds in clean water until they sprout and grow shoots approximately 2 inches (5 cm) long. Barley grass is an extraordinarily rich source of many vitamins, minerals, and amino acids, although it does not, as sometimes claimed, contain absolutely all the nutrients needed for human health. The dried shoot is approximately 4% glutamic acid (needed for recharging antioxidants), 4% methionine (needed for the production of natural SAM-e), 3% vitamin C, 1% valine, and 1% calcium. A single tablespoon contains a day's supply of beta-carotene, betaine, biotin, boron, copper, iron, lutein, magnesium, niacin, riboflavin, and thiamine. It also contains nutritionally significant amounts of alpha-linoleic acid, oryzanol, potassium, selenium, zinc, and the tocopherols that make up vitamin E.