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<<   作成日時 : 2009/12/29 23:55   >>

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画像 中国人は4000年以上にわたり、緑茶の持つ医学的効用を知っている。フェニキア人がブドウとワインを広めたように、緑茶も貿易商や旅行者が世界中に広めた。赤ワインのresveratrolのように、緑茶の効用は信じられないほどである。緑茶の秘密はブドウの種やワインにも含まれるカテキン・ポリフェノールが非常に多いことによる。
 同じ原料から製造工程の違いで、白茶、紅茶、ウーロン茶、緑茶は作られる。
 発酵と酸化によりポリフェノールは減ってしまう。このプロセスを経ていない白茶や緑茶はカテキンが多い。緑茶のカテキンはポリフェノールフラボノイドの80%を占めるが、紅茶では20-30%である。
 抗酸化・老化防止効果:緑茶のカテキンはビタミンC・Eの25-100倍の作用がある。一杯の緑茶で、ブロッコリ、ホウレンソウ、ニンジン、イチゴより多くの抗酸化活性を持つ。フリー・ラジカルのよる損傷効果を減らす効果がある。
 抗凝固作用:血小板に作用して脳卒中や心臓発作を予防する。
 抗ウイルス作用:カテキンがインフルエンザウイルスに接着し人の粘膜に感染するのを防ぐ。C型肝炎を予防する。
 降圧作用:血管収縮させる酵素を抑制する。
 抗がん作用:ガンの発育を抑制する。
 抗コレステロール:コレステロールの吸収を阻害して、LDLを減らしHDLを増加させる。
 血糖降下作用:砂糖をグルコースに分解する酵素を抑制して高血糖を制御する。 腸内細菌叢の保持:
 体重減少効果:脂肪の燃焼を促進する。
 口臭予防:口腔内の細菌を減らす
 虫歯予防:抗菌作用
 骨関節炎予防:ECGCというカテキンが関節炎を抑制。

 3分ほどお湯につけないとカテキンが十分抽出されない。
 コーヒーの20%ほどカフェインを含む。レモンがカテキンの吸収を高める。
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緑茶成分、新型インフル予防に有効
http://www.cabrain.net/news/article/newsId/25726.html
 緑茶に含まれているカテキンの一種である「エピガロカテキンガレート(EGCg)」が新型インフルエンザの感染予防に有効であることが、伊藤園(本社=東京都渋谷区)と静岡県立大薬学部の鈴木隆教授との共同研究で明らかになった。
 研究ではまず、新型インフルエンザ(A/H1N1型)、季節性インフルエンザ(A/H3N2型)、鳥インフルエンザ(A/H5N3型)の各ウイルス液と EGCgを混合し、実験用の細胞に感染させて一定期間培養した後、感染した細胞を数えた。続いて、EGCgと混合していないウイルス液を細胞に添加した場合の感染細胞数を100%として、感染細胞数が半分に抑制されるEGCgの濃度を算出した。
 研究結果によると、新型インフルエンザ、季節性インフルエンザ、鳥インフルエンザの感染を半分に抑制するEGCgの濃度は、それぞれ0.12μM(マイクロモラー)、0.52μM、0.55μM。 3種すべてに感染抑制作用を示し、新型インフルエンザに対する作用が最も強いことが分かった。一方、インフルエンザの予防・治療に用いられる「アマンタジン」の感染抑制濃度は、それぞれ50μM以上、3.18μM、0.59μMで、EGCgがアマンタジンよりも低い濃度でウイルスの感染抑制作用を示した。
 同社によると、緑茶でうがいをすることがインフルエンザの予防に効果があることがこれまでに一部報告されており、緑茶に含まれるカテキンの中でもEGCgが最も強い活性を持つことが明らかになっていた。
 同社は研究結果から、EGCgが型に関係なくインフルエンザを予防できる可能性が示され、改めて緑茶がインフルエンザの予防に有効であることが示唆されたとしている。
更新:2009/12/25 12:00   キャリアブレイン

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From Weight Loss to Anti-Aging Effects―12 Health Benefits of Green Tea
How much, how often and what not to add to your tea.
From The Longevity Factor by Joseph Maroon, M.D.
http://health.msn.com/nutrition/articlepage.aspx?cp-documentid=100249956

The Chinese have known about the medicinal benefits of green tea for at least 4,000 years. Just as grapes and wine were spread throughout the world initially by the Phoenicians and later by other traders, tea was introduced to countries worldwide by tradesmen and travelers. The health benefits of green tea border on the unbelievable and are very similar to those described for resveratrol and red wine. The secret of green tea is that it is extremely rich in catechin polyphenols, the same catechins found coating the seeds of grapes and in wine.

The tea plant itself has the scientific name Camellia sinensis. Although it is native to China, it has spread to and is now cultivated in many countries across the world, predominantly in the tropical and subtropical zones.

Black, green, oolong and white tea are all prepared from the same leaves. The difference is in the harvesting, drying, fermentation and roasting. Black tea roasting takes place after the harvested leaves are crushed and undergo browning (also called fermentation or oxidation). Oolong tea is allowed to undergo moderate drying and fermentation. Green tea is created when the tea leaves are steamed or heated immediately after harvesting.

White tea is made from young tea buds and does not undergo fermentation. The fermentation and oxidation process naturally reduces the polyphenol content of black tea. Green tea and white tea have the highest concentrations of the active catechins because they do not go through this process. Therefore they are the best dietary source of this compound. Catechins represent 80 percent of polyphenol flavonoids in green tea, whereas in black tea they represent approximately 20 percent to 30 percent.

There are now thousands of scientific articles detailing the wealth of health benefits provided by catechins found in green tea:

* Antioxidative and anti-aging effects: The catechins found in tea are twenty-five to one hundred times as potent as vitamins C and E. One cup of green tea provides more antioxidant activity than a serving of broccoli, spinach, carrots or strawberries. This activity reduces the damaging effects of free radicals.
* Anticlotting effect: Green tea catechins act on blood platelets to prevent stickiness and clotting, reducing the number of strokes and heart attacks.
* Antiviral and cold prevention effects: Green tea catechins attach themselves firmly to the surface of the flu virus and prevent it from infecting the human oral and nasal mucous membranes. Red wine and tea also protect against hepatitis C.
* Control of high blood pressure: Green tea catechins suppress the enzyme that contracts blood vessels, easing high blood pressure.
* Cancer prevention: Catechins in green tea interfere with cancer development in all three stages.
* Green tea catechins control cholesterol by blocking enzymes in the intestine that contribute to the absorption of cholesterol. They suppress LDL and elevate HDL.
* They control high blood sugar levels by suppressing the enzymes that break down sugar into glucose.
* They maintain healthy intestinal flora by decreasing the number of harmful bacteria and fostering the growth of “good” bacteria such as bifidobacteria.
* They contribute to weight loss: Together with the caffeine in tea, catechins accelerate the burning of fat. Men given a combination of caffeine and green tea extract burned more calories and lost more weight than those given only caffeine or a placebo.
* They prevent bad breath: Catechins neutralize unpleasant oral odors by reducing oral bacteria.
* They prevent tooth decay: Catechins have a strong antibacterial effect and prevent the buildup of dental plaque.
* They inhibit osteoarthritis: Studies using human cartilage cells demonstrated that a catechin known as ECGC protects against inflammatory degeneration and arthritis.

There are several additional points to keep in mind. To obtain these dramatic health benefits from green tea, relatively large amounts must be consumed. A minimum of three to ten cups a day is recommended. Larger amounts, up to ten cups a day, have been used for cancer prevention, and in Japan these are supplemented with additional green tea tablets for the treatment of cancer.

Also, not all green tea is equal in its content of catechins. Premium green teas contain at least 100 milligrams of the catechin EGCG, whereas some green tea bags from commercial food giants can contain one-third or even less. Brewing is a major factor, too. Unless you are drinking a fusion, in which the green tea is already dissolved in water, the tea bag should be placed into boiling water for approximately three minutes to get the maximal diffusion of polyphenols.

Caffeine content also is a factor. Green tea usually contains about 20 percent of the caffeine found in a cup of regular coffee. High consumption may cause agitation, anxiety and irritability in those susceptible to caffeine.

Lemon and milk are frequent additives to various teas. The citric acid in lemons appears to enhance the absorbability of the catechins in green tea. Milk, on the other hand, may negate some of the health benefits, particularly in black tea. (The casein proteins in milk are thought to adhere to the catechins and offset some of their health benefits.) One researcher suggested that the reason that the British, who are passionate about tea, have failed to make as much headway against cardiovascular disease as the French with their red wine and the Asians with their green tea is their penchant for adding milk to their tea.

Despite extremely high consumption in some countries, the only negative effect reported from drinking green tea is insomnia secondary to the caffeine content. These observations parallel the absence of side effects seen in similar studies using resveratrol.

Discover more health benefits in Dr. Joseph Maroon’s The Longevity Factor.

About the Author

Dr. Joseph Maroon, the author of The Longevity Factor (Copyright (c) 2009 by Maroon Enterprises), studied medicine at Indiana University, Georgetown and Oxford University. He began his practice in 1982 at the University of Pittsburgh, where in 1999 he was named the Heindl Scholar and Vice Chairman of the department of Neuroscience. In 1986, he was named President of the Congress of Neurological Surgeons, the largest society of its kind in North America. He has been the team neurosurgeon for the Pittsburgh Steelers for the past 20 years, and has developed a computerized scanning system to evaluate concussions that has been adopted throughout the NFL, NHL, NBA, NASCAR, as well as more than 1,000 high schools and colleges. Maroon has remained an active athlete since college, having competed in more than 50 triathlons, including five Ironman competitions.

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緑茶の医学的効用・・・・医師の一分さん
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龍涙
2009/12/30 18:47

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