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Photo © Steven Foster
Introduction
The tea plant is a small, variable, evergreen shrub with white flowers that is native to mountainous regions of China, Japan, and India.1 It is cultivated around the world in countries with tropical and subtropical climates.2 The plant can grow to 30 feet, but usually is pruned to 2 to 3 feet.3 The young leaves and the dried leaf bud are used and are considered to have a better quality than older leaves.3 History and Cultural Significance
Tea is believed to have originated with the Buddha. While meditating, Buddha fell asleep, and upon awakening, he cut off his eyelids in disgust. Tea plants grew from where his eyelids landed, so that he could give the gift of awareness to his disciples.1 Tea is used extensively in the traditional medicine systems of China, Hong Kong, Japan, and Korea.4 In China, the use of tea as a beverage dates back to 2700 BCE.4 Next to water, tea is the most widely consumed beverage in the world. The Chinese have a ritual tea drinking ceremony which started during the Sung Dynasty. Traditionally, tea was rarely used as a medicine except as a stimulant, astringent (drying agent), and in infusions (teas) to relieve headaches.5 Modern Research
Studies on black or green tea leaf have demonstrated that they may have positive effects in the areas of cardiovascular health, osteoporosis, obesity, and bowel conditions.4 Green tea contains antioxidants, which have been shown to inhibit cardiovascular disease development and inflammation.6 Tea may also have psychological and neurological effects, such as increases in alertness and information processing, that are not due to caffeine but a chemical (theanine) in the tea leaves.7 Future Outlook
International tea production is projected to increase from the 1993-95 average of 1.97 million tons to 2.7 million.4 In 1999, the U.S. imported 16,961,460 pounds of green tea, 187,765,660 pounds of black tea, and 7,777,542 pounds of instant tea. According to the United Nations Food and Agriculture Organization, there is an increasing body of scientific evidence that both green and black tea can contribute significantly to a healthy lifestyle, and their regular use should be promoted internationally.4 Organizations such as World Green Tea Association are forming to advocate tea use and knowledge and to foster economic interest in growing, producing, and consuming green tea.8 References
1 Bown D, Encyclopedia of Herbs and Their Uses. London: Dorling Kindersley Ltd; 2001. 2 Roberts JE, Tyler VE. Tyler’s Herbs of Choice, 2nd ed. New York: The Haworth Herbal Press; 2000. 3 Leung AY, Foster S. Encyclopedia of Common Natural Ingredients. 2nd ed. New York: Wiley & Sons; 1996. 4 Blumenthal M, Hall T, Goldberg A, Kunz T, Dinda K, Brinckmann J, et al, editors. The ABC Clinical Guide to Herbs. Austin, TX: American Botanical Council; 2003. 5 Grieve M. A Modern Herbal. Vol II. New York: Dover Publications; 1971. 6 Henson S. Green tea and cancer care. HerbClip. June 15, 2004 (No. 020141-258) Austin, TX: American Botanical Council. Green tea catechins and L-theanine in integrative cancer care by Huber L. Alternative and Complementary Therapies. December 2003:294-298. 7 The health benefits of tea. HerbalGram. 1996; No. 37:38. 8 Aims of World Green Tea Association. Available at: http://www.o-cha.net/english/association/index.html. Accessed March 20, 2005.
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