"Better to be deprived of food for three days, than tea for one." (Ancient Chinese Proverb)

    Is any other food or drink reported to have as many health benefits as green tea? The Chinese have known about the medicinal benefits of green tea since ancient times, using it to treat everything from headaches to depression. In her book Green Tea: The Natural Secret for a Healthier Life, Nadine Taylor states that green tea has been used as a medicine in China for at least 4,000 years.

    Today, scientific research in both Asia and the west is providing hard evidence for the health benefits long associated with drinking green tea. For example, in 1994 the Journal of the National Cancer Institute published the results of an epidemiological study indicating that drinking green tea reduced the risk of esophageal cancer in Chinese men and women by nearly sixty percent. University of Purdue researchers recently concluded that a compound in green tea inhibits the growth of cancer cells. There is also research indicating that drinking green tea lowers total cholesterol levels, as well as improving the ratio of good (HDL) cholesterol to bad (LDL) cholesterol.

    To sum up, here are just a few medical conditions in which drinking green tea is reputed to be helpful:

    * cancer

    * rheumatoid arthritis

    * high cholesterol levels

    * cariovascular disease

    * infection

    * impaired immune function

    What makes green tea so special?

    The secret of green tea lies in the fact it is rich in catechin polyphenols, particularly epigallocatechin gallate (EGCG). EGCG is a powerful anti-oxidant: besides inhibiting the growth of cancer cells, it kills cancer cells without harming healthy tissue. It has also been effective in lowering LDL cholesterol levels, and inhibiting the abnormal formation of blood clots. The latter takes on added importance when you consider that thrombosis (the formation of abnormal blood clots) is the leading cause of heart attacks and stroke.

    Links are being made between the effects of drinking green tea and the "French Paradox." For years, researchers were puzzled by the fact that, despite consuming a diet rich in fat, the French have a lower incidence of heart disease than Americans. The answer was found to lie in red wine, which contains resveratrol, a polyphenol that limits the negative effects of smoking and a fatty diet. In a 1997 study, researchers from the University of Kansas determined that EGCG is twice as powerful as resveratrol, which may explain why the rate of heart disease among Japanese men is quite low, even though approximately seventy-five percent are smokers.

    Why don't other Chinese teas have similar health-giving properties? Green, oolong, and black teas all come from the leaves of the Camellia sinensis plant. What sets green tea apart is the way it is processed. Green tea leaves are steamed, which prevents the EGCG compound from being oxidized. By contrast, black and oolong tea leaves are made from fermented leaves, which results in the EGCG being converted into other compounds that are not nearly as effective in preventing and fighting various diseases.

    Other Benefits

    New evidence is emerging that green tea can even help dieters. In November, 1999, the American Journal of Clinical Nutrition published the results of a study at the University of Geneva in Switzerland. Researchers found that men who were given a combination of caffeine and green tea extract burned more calories than those given only caffeine or a placebo.

    Green tea can even help prevent tooth decay! Just as its bacteria-destroying abilities can help prevent food poisoning, it can also kill the bacteria that causes dental plaque. Meanwhile, skin preparations containing green tea - from deodorants to creams - are starting to appear on the market.

    Harmful Effects?

    To date, the only negative side effect reported from drinking green tea is insomnia due to the fact that it contains caffeine. However, green tea contains less caffeine than coffee: there are approximately thirty to sixty mg. of caffeine in six - eight ounces of tea, compared to over one-hundred mg. in eight ounces of coffee.

    “寧可三日無米，不可一頓無茶”（中國古諺語）

    還有其它食物或者飲料能像綠茶一樣有益于我們的健康嗎？中國人自古以來就懂得利用綠茶的醫用價值，并用于治療頭痛和意志消沉等。Nadine Taylor在她《綠茶：健康的天然奧秘》一書中說道，中國早在4000年前就已將綠茶入藥。

    長久以來，人們都將飲用綠茶與健康聯系起來，如今亞洲和西方的科學研究正為此提供了有力的證據。例如，1914年國家癌癥研究所發表了一項關于流行病學的研究，結果表明飲用綠茶使中國男性和女性中食道癌的發病率降低將近60％。最近，普渡大學的學者研究發現，綠茶中的一種化合物能夠抑制癌癥細胞的生長。同樣有研究表明，飲用綠茶能降低總膽固醇水平和提高有益膽固醇（高密度脂蛋白）與有害膽固醇（低密度脂蛋白）的比率。

    總而言之，飲用綠茶是對很多疾病都有益處，這里僅做一些列舉：

    ·癌癥

    ·風濕性關節炎

    ·高膽固醇

    ·心血管疾病

    ·傳染病

    ·免疫功能受損

    什么使綠茶如此特別？

    綠茶的秘密在于它富含兒茶素，特別是沒食子兒茶素沒食子酸酯(EGCG)。EGCG是一種強抗氧化劑：不僅能抑制癌細胞生長，殺滅癌細胞，同時也不損害健康的組織。除此之外還能有效地降低LDL膽固醇水平和抑制血塊形成異常。而血栓癥（異常血塊的形成）正是導致心臟病和中風的主要原因，考慮到這點，后者就顯得尤為重要。

    人們將飲用綠茶的功效與“法蘭西悖論”聯系起來。多年以來，研究人員都無法解釋這個事實，盡管法國人的日常飲食富含脂肪，但是心臟病的發病率卻比美國人低。發現答案原來是紅酒中含有多酚物質白藜蘆醇，它能夠限制吸煙和脂肪所帶來的副作用。在1997年的一項研究中，堪薩斯大學的研究員測定出EGCG的功效是白藜蘆醇的兩倍，這就解釋了為什么日本人中將近75％都是吸煙者，而心臟病的發病率卻十分低。

    為什么其它中國茶沒有類似的保健功能？綠茶、烏龍茶和紅茶均取自山茶花的葉子，是綠茶的加工方式使它顯得與眾不同。綠茶的茶葉通過蒸煮防止了EGCG化合物被氧化。相比之下，紅茶和烏龍茶的茶葉都是發酵而成的，這會使EGCG轉化為其它化合物，預防和治療各種疾病的效果都遠不如前者。　

    其它益處

    新的證據表明綠茶甚至能幫助節食者。1999年11月，美國臨床營養學報刊登了一項瑞士日內瓦城大學的研究結果。研究員發現，結合咖啡因和綠茶提取物使用的人比單獨使用咖啡因或安慰劑的人能燃燒更多的卡路里。

    綠茶甚至能幫助預防蛀牙！正如它的殺菌能力可以防止食物中毒，它也能殺滅引起牙菌斑的細菌。同時，從除臭劑到乳霜——各種綠茶配方的護膚品正開始在市場上出現。

    不良影響

    關于飲用綠茶的不良影響，到目前為止唯一報導的就是失眠，因為綠茶中含有咖啡因。不過，綠茶中的咖啡因含量要比咖啡低：6到8盎司茶里大約含有30到60毫克咖啡因，相比之下，8盎司咖啡里就含有超過100毫克咖啡因。