Green Tea (Camellia sinensis)
Parts used and where grown: All teas (green, black, and oolong) are derived from the same plant, Camellia sinensis. The difference is in how the plucked leaves are prepared. The leaves of the tea plant are used both as a social and medicinal beverage. Green tea, unlike black and oolong tea, is not fermented, so the active constituents remain unaltered in the herb.
In what conditions might green tea be supportive?
Â¥ cancer risk reduction
Â¥ gingivitis (periodontal disease)
Â¥ high cholesterol
Â¥ high blood pressure
Â¥ high triglycerides
Â¥ immune function
Historical or traditional use: According to Chinese legend, tea was discovered accidentally by an emperor 4,000 years ago. Since then, traditional Chinese medicine has recommended green tea for headaches, body aches and pains, digestion, depression, immune enhancement, detoxification, as an energizer, and to prolong life. Modern research has confirmed many of these health benefits.
Active constituents: Green tea contains volatile oils, vitamins, minerals, and caffeine, but the active constituents are polyphenols, particularly the catechin called epigallocatechin gallate (EGCG). The polyphenols are believed to be responsible for most of green teaÃ•s roles in promoting good health.1
Research demonstrates that green tea guards against cardiovascular disease in many ways. Green tea lowers total cholesterol levels and improves the cholesterol profile (the ratio of LDL cholesterol to HDL cholesterol), reduces platelet aggregation, and lowers blood pressure.2 3 4 5 The polyphenols in green tea have also been shown to lessen the risk of cancers of several sites, stimulate the production of several immune system cells, and have anti-bacterial propertiesÃ‘even against the bacteria that cause dental plaque.6 7 8
How much should I take? Much of the research documenting the health benefits of green tea is based on the amount of green tea typically drunk in Asian countriesÃ‘about three cups per day (providing 240-320 mg of polyphenols). To brew green tea, 1 U.S. teaspoon (5 grams) of green tea leaves are combined with 250 ml (1 cup) of boiling water and steeped for three minutes. Tablets and capsules containing standardized extracts of polyphenols, particularly EGCG, are available; some are decaffeinated and provide up to 97% polyphenol contentÃ‘which is equivalent to drinking four cups of tea.
Are there any side effects or interactions? Green tea is extremely safe. The most common adverse effect reported from consuming large amounts of green tea is insomnia, anxiety, and other symptoms caused by the caffeine content in the herb.
1. Graham HN. Green tea composition, consumption, and polyphenol chemistry. Prev Med 1992;21:334-350. 2. Kono S, Shinchi K, Ikeda N, et al. Green tea consumption and serum lipid profiles: A cross-sectional study in Northern Kyushu, Japan. Prev Med 1992;21:526-531. 3. Yamaguchi Y, Hayashi M, Yamazoe H, et al. Preventive effects of green tea extract on lipid abnormalities in serum, liver and aorta of mice fed an atherogenic diet. Nip Yak Zas 1991;97(6):329-337. 4. Sagesaka-Mitane Y, Milwa M, Okada S. Platelet aggregation inhibitors in hot water extract of green tea. Chem Pharm Bull 1990;38(3):790-793. 5. Stensvold I, Tverdal A, Solvoll K, et al. Tea consumption. Relationship to cholesterol, blood pressure, and coronary and total mortality. Prev Med 1992;21:546-553. 6. Stoner GD, Mukhtar H. Polyphenols as cancer chemopreventive agents. J Cell Bioch 1995;22:169-180. 7. You SQ. Study on feasibility of Chinese green tea polyphenols (CTP) for preventing dental caries. Chin J Stom 1993;28(4):197-199. 8. Hamilton-Miller JM. Antimicrobial properties of tea (Camellia sinensis L.). Antimicro Ag Chemo 1995;39(11):2375-2377.
*These statements have not been evaluated by the Food and Drug Administration. These products are not intended to diagnose, treat, cure or prevent any disease.