View source for Green tea

{{For|the 2003 Chinese film|Green Tea (film)}}''

The beverage '''green tea''' ({{zh-stp|s=[[wiktionary:绿|绿]][[wiktionary:茶|茶]]|t=[[wiktionary:綠|綠]][[wiktionary:茶|茶]]|p=lǜchá}}) is a "true" [[tea]] (i.e., ''[[Camellia sinensis]]'') that has undergone minimal [[oxidation]] during processing.

Green tea is popular in [[China]], [[Korea]], [[Uzbekistan]], [[Kyrgyzstan]], [[Kazakhstan]], [[Japan]], [[Pakistan]], [[Taiwan]], [[Hong Kong]], [[Morocco]], and the [[Middle East]]. Recently, it has become more widespread in the [[West]], where traditionally [[black tea]] is consumed. 

== Chinese green teas ==
[[Image:Maojian.jpg|thumbdXi Hu Longjing.png|thumb| An example of a slightly higher grade of Chinese green tea, possibly [[Longjing tea|Longjing]].]] 
[[Image:Twinings Gunpowder tea in pile.jpg|thumb|A pile of the [[Twinings]] brand [[gunpowder tea]], a low-grade variety of Chinese green tea]]
==== Zhejiang Province ====
[[Zhejiang]] is home to the most famous of all teas, Xi Hu Longjing, as well as many other high-quality green teas. 
; ''[[Longjing tea|Longjing]]'': The most well-known of [[China Famous Tea|famous Chinese teas]] from [[Hangzhou]], its name in Chinese means ''dragon well''. It is pan-fried and has a distinctive flat appearance. Falsification of Longjing is very common, and most of the tea on the market is in fact produced in [[Sichuan]] Province{{Fact|date=August 2007}} and hence not authentic Longjing. 
; ''[[Hui Ming Tea|Hui Ming]]'': Named after a temple in [[Zhejiang]].
; ''[[Long Ding tea|Long Ding]]'': A tea from [[Kaihua County]] known as ''Dragon Mountain''.
; ''[[Hua Ding tea|Hua Ding]]'': A tea from [[Tiantai County]] and named after a peak in the Tiantai mountain range.
; ''[[Qing Ding tea|Qing Ding]]'': A tea from Tian Mu, also known as ''Green Top''.
;''[[Gunpowder tea|Gunpowder]]'': A popular tea also known as ''zhuchá''. It originated in [[Zhejiang]] but is now grown elsewhere in [[China]].

==== Jiangsu Province ====
;''[[Bi Luo Chun tea|Bi Luo Chun]]'': A [[China Famous Tea|Chinese famous tea]] also known as ''Green Snail Spring'', from [[Dong Ting]]. As with [[Longjing]], falsification is common and most of the tea marketed under this name may, in fact, be grown in [[Sichuan]].
;''[[Rain Flower tea|Rain Flower]]'': A tea from [[Nanjing]].
;''[[Shui Xi Cui Bo]]''

==== Hubei Province ====
; ''[[Yu Lu tea|Yu Lu]]'': A steamed tea known as ''Gyokuro (Jade Dew)'' made in the [[Japanese cuisine|Japanese]] style.

==== Henan Province ====
;''[[Mao Jian tea|Xin Yang Mao Jian]]'': A [[China Famous Tea|Chinese famous tea]] also known as ''Green Tip''.

====Jiangxi Province====
;''[[Chun Mee tea|Chun Mee]]'': Name means "precious [[eyebrows]]"; from [[Jiangxi]], it is now grown elsewhere.
;''[[Gou Gu Nao]]'': A well-known tea within China and recipient of numerous national awards.
;''[[Yun Wu tea|Yun Wu]]'': A tea also known as ''Cloud and Mist''.

====Anhui Province====
[[Anhui]] Province is home to three [[China Famous Tea|Chinese famous teas]].
;''[[Da Fang tea|Da Fang]]'': A tea from [[Mount Huangshan]] also known as ''Big Square''.
;''[[Mao feng tea|Huangshan Mao Feng]]'': A [[China Famous Tea|Chinese famous tea]] from [[Mount Huangshan]].
;''[[Lu An Guapian tea|Lu An Guapian]]'': A [[China Famous Tea|Chinese famous tea]] also known as ''Melon Seed''.
;''[[Hou Kui tea|Hou Kui]]'': A [[China Famous Tea|Chinese famous tea]] also known as ''Monkey tea''.
;''[[Tun Lu tea|Tun Lu]]'': A tea from [[Tunxi District]].
;''[[Huo Qing tea|Huo Qing]]'': A tea from [[Jing County, Anhui|Jing County]], also known as ''Fire Green''.
; ''[[Hyson]]'': A medium-quality tea from many [[Province (China)|provinces]], an early-harvested tea.

==Japanese green teas==
[[Image:Green Tea.jpg|thumb|Japanese green tea]]
[[Image:Yamamotoyama Genmaicha.jpg|thumb|''Genmaicha'' green tea]]
Green tea ({{nihongo|'''Ryokucha'''|緑茶|ryokucha}}) is so ubiquitous in [[Japan]] that it is more commonly known as "tea" ({{nihongo|''ocha''|お茶|ocha}}) and even "Japanese tea" ({{nihongo|''nihoncha''|日本茶|nihoncha}}). Types of tea are commonly graded depending on the quality and the parts of the plant used. There are large variations in both price and quality within these broad categories, and there are many specialty green teas that fall outside this spectrum. The very best Japanese green tea is said to be that from the [[Uji]] region of [[Kyoto]]<ref>http://www.city.uji.kyoto.jp/data/sfnFoWN1iBexH3K/Index.htm</ref>. [[Shizuoka Prefecture|Shizuoka Prefecture（静岡県）]]<ref>http://en.wikipedia.org/wiki/Shizuoka_Prefecture</ref> is also famous for its green tea.

; 玉露 [[Gyokuro]] (''Jade Dew'')
:Selected from a grade of green tea known as Ten-cha (天茶), Gyokuro's name refers to the pale green color of the infusion. The leaves are grown in the shade before harvest, which alters their flavor.
; 抹茶 [[Matcha]] (''rubbed tea''): A high-quality powdered green tea used primarily in the [[tea ceremony]]. Matcha is also a popular [[green tea ice cream|flavour of ice cream]] and other sweets in Japan.
; 煎茶 [[Sencha tea|Sencha]] (''broiled tea''): A common green tea in Japan made from leaves that are exposed directly to sunlight. 
; 玄米茶 [[Genmaicha]] (''Brown-Rice tea''): ''maicha'' and roasted ''genmai'' ([[brown rice]]) blend.
; 冠茶 [[Kabusecha tea|Kabusecha]] (''covered tea''): ''kabusecha'' is ''sencha'' tea, the leaves of which have grown in the shade prior to harvest, although not for as long as Gyokuro. It has a more delicate flavor than Sencha.
; 番茶 [[Bancha tea|Bancha]] (''common tea''): Sencha harvested as a second-flush tea between summer and autumn. The leaves are larger than Sencha and the flavour is less full.
; 焙じ茶 [[Hojicha|Hōjicha]] (''pan fried tea''): A roasted green tea.
; 茎茶 [[Kukicha tea|Kukicha]] (''stalk tea''): A tea made from stalks produced by harvesting one bud and three leaves.
; 玉緑茶 [[Tamaryokucha]]: A tea that has a tangy, berry-like taste, with a long almondy aftertaste and a deep aroma with tones of citrus, grass, and berries. 

; Okinawan Tea

==Other green teas==
* [[Ceylon tea (green)|Green Tea from Ceylon]]

==Brewing==
Generally, 2.25 grams of tea per 6 ounces of water, or about one teaspoon of green tea per cup, should be used. Green teas should be prepared with 180°F to 190°F (82°C to 88°C) water (not boiling) and steeped 2 to 3 minutes.

==Potential effects of green tea on health==
{{mainarticle|Potential effects of tea on health}}

===History===
There is archaeological evidence that suggests that tea has been consumed for almost 5000 years, with India and China being two of the first countries to cultivate it. Green tea has been used as traditional medicine in areas such as India, China, Japan and Thailand to help everything from controlling bleeding and helping heal wounds to regulating body temperature, blood sugar and promoting digestion.

The ''Kissa Yojoki'' (''Book of Tea''), written by [[Zen]] priest [[Eisai]] in [[1191]], describes how drinking green tea can have a positive effect on the five vital organs, especially the [[heart]]. The book discusses tea's medicinal qualities, which include easing the effects of [[alcohol]], acting as a [[stimulant]], curing blotchiness, quenching thirst, eliminating indigestion, curing [[beriberi|beriberi disease]], preventing [[fatigue (physical)|fatigue]], and improving [[urinary]] and [[brain]] function. Part One also explains the shapes of tea plants, tea flowers, and tea leaves, and covers how to grow tea plants and process tea leaves. In Part Two, the book discusses the specific dosage and method required for individual physical ailments.

===Unproven claims===
Green tea has been credited with providing a wide variety of health benefits, many of which have not been validated by scientific evidence.  These claims and any for which academic citations are currently missing are listed here:

* Stopping certain [[neurodegenerative disease]]s such as [[Alzheimer's disease|Alzheimer's]] and [[Parkinson's syndrome|Parkinson's]]{{Fact|date=April 2007}}
* Preventing/treating cancer <ref>http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=16785249</ref>
* Treating [[multiple sclerosis]] <ref>http://www.annalsnyas.org/cgi/content/abstract/928/1/274</ref>
* Preventing the degradation of [[cell (biology)|cell]] [[cell membrane|membranes]] by neutralizing the spread of [[Radical (chemistry)|free radicals]] (which occurs during the process of oxidation). <ref>http://www.nadraszky.com/fitness/archives/green-tea-health-benefits.html</ref>
* Reducing the negative effects of [[LDL|LDL cholesterol]] (bad cholesterol) by lowering levels of triglycerides and increasing the production of [[HDL|HDL cholesterol]] good cholesterol. 
* Increasing fat [[oxidation]] (helps the body use fat as an energy source) and raising [[metabolism]]. <ref>http://www.actabit.com/diet-nutrition/how-effective-is-green-tea-for-weight-loss</ref>
* Joy Bauer, a New York City nutritionist, says [the catechins in green tea] increase levels of the metabolism speeding brain chemical norepinephrine. 
* Japanese researchers claim if you drink five cups of green tea a day, you'll burn 70 to 80 extra calories.  Dr. Nicholas Perricone, an anti-aging specialist, appeared on the Oprah Winfrey show and told Oprah's viewers they can lose 10 lbs. in 6 weeks drinking green tea instead of coffee 
* The major concern with drinking too much green tea is the high amount of [[caffeine]] it contains. Too much caffeine can cause [[nausea]], [[insomnia]] or [[frequent urination]]. <ref>http://www.cancer.org/docroot/ETO/content/ETO_5_3X_Green_Tea.asp?sitearea=ETO</ref>
* Drinking green tea mixed with honey can oftentimes have a soothing effect on a sore throat.

===United States Food and Drug Administration (FDA)===
The article ''Tea: A Story of Serendipity''<ref>http://www.fda.gov/FDAC/features/296_tea.html</ref> appeared in the March 1996 issue of [[FDA]] Consumer Magazine and looked at the potential benefits of green tea.  At that time they had not done any reviews of the potential benefits of green tea and were waiting to do it until health claims were filed. They have since denied two petitions to make qualified health claims as to the health benefits of green tea.  <ref>http://www.medterms.com/script/main/art.asp?articlekey=38989</ref>

On June 30, 2005, in response to "Green Tea and Reduced Risk of Cancer Health Claim", they stated:
"FDA concludes that there is no credible evidence to support qualified health claims for green tea consumption and a reduced risk of gastric, lung, colon/rectal, esophageal, pancreatic, ovarian, and combined cancers.  Thus, FDA is denying these claims.  However, FDA concludes that there is very limited credible evidence for qualified health claims specifically for green tea and breast cancer and for green tea and prostate cancer, provided that the qualified claims are appropriately worded so as to not mislead consumers." <ref>http://www.cfsan.fda.gov/~dms/qhc-gtea.html</ref>

On May 9, 2006, in response to "Green Tea and Reduced Risk of Cardiovascular Disease", they concluded "there is no credible evidence to support qualified health claims for green tea or green tea extract and a reduction of a number of risk factors associated with CVD." <ref>http://www.cfsan.fda.gov/~dms/qhcgtea2.html</ref>

However in October 2006, the FDA approved an ointment based on green tea.  New Drug Application (NDA) number N021902, for kunecatechins ointment 15% (proprietary name Veregen) was approved on October 31, 2006 <ref>http://www.fda.gov/cder/rdmt/InternetNME06.htm</ref>, and added to the "Prescription Drug Product List" in October 2006. <ref>http://www.fda.gov/cder/rxotcdpl/pdpl_200610.htm</ref> Kunecatechins ointment is indicated for the topical treatment of external genital and perianal warts. <ref>http://www.fda.gov/cder/foi/label/2006/021902lbl.pdf</ref>

===Scientific studies===
A [[2006]] study published in the September 13 issue of the [[Journal of the American Medical Association]] concluded "Green tea consumption is associated with reduced shrut, and trimroots induced mortality due to all causes and due to cardiovascular disease but not with reduced mortality due to cancer." The study, conducted by the [[Tohoku University]] School of Public Policy in Japan, led by Dr. Daniel Rupieh-Haghani, followed 40,530 Japanese adults, ages 40-79, with no history of [[stroke]], coronary heart disease, or cancer at baseline beginning in [[1994]]. The study followed all participants for up to 11 years for death from all causes and for up to 7 years for death from a specific cause. Participants who consumed 5 or more cups of tea per day had a 16 percent lower risk of all-cause mortality and a 26 percent lower risk of cardiovascular disease than participants who consumed less than one cup of tea per day. The study also states, "If green tea does protect humans against CVD or cancer, it is expected that consumption of this beverage would substantially contribute to the prolonging of life expectancy, given that CVD and cancer are the two leading causes of death worldwide."<ref>http://jama.ama-assn.org/cgi/content/abstract/296/10/1255</ref>
<ref>http://www.denverpost.com/nationworld/ci_4326770 Article in the Denver Post</ref>

A study published in the February 2006 edition of the American Journal of Clinical Nutrition concluded "A higher consumption of green tea is associated with a lower prevalence of cognitive impairment in humans."<ref>http://www.ajcn.org/cgi/content/abstract/83/2/355</ref> <ref>http://www.foodnavigator.com/news/ng.asp?id=66142</ref>

In May 2006, researchers at [[Yale School of Medicine|Yale University School of Medicine]] weighed in on the issue with a review article that looked at more than 100 studies on the health benefits of green tea. They pointed to what they called an "Asian paradox," which refers to lower rates of heart disease and cancer in Asia despite high rates of [[cigarette]] smoking. They theorized that the 1.2 liters of green tea that is consumed by many Asians each day provides high levels of [[polyphenol]]s and other [[antioxidant]]s. These compounds may work in several ways to improve cardiovascular health, including preventing blood platelets from sticking together (This [[anticoagulant]] effect is the reason doctors warn surgical patients to avoid green tea prior to procedures that rely on a patient's clotting ability) and improving cholesterol levels, said the researchers, whose study appeared in the May issue of the ''Journal of the American College of Surgeons''. Specifically, green tea may prevent the oxidation of [[LDL cholesterol]] (the "bad" type), which, in turn, can reduce the buildup of plaque in arteries, the researchers wrote.<ref>http://www.yale.edu/opa/newsr/06-06-01-01.all.html</ref>

A study published in the August 22, 2006 edition of Biological Psychology looked at the modification of the stress response via [[L-Theanine]], a chemical found in green tea.  It "suggested that the oral intake of L-Theanine could cause anti-stress effects via the inhibition of cortical neuron excitation."<ref>http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Retrieve&dopt=AbstractPlus&list_uids=16930802&query_hl=3&itool=pubmed_docsum</ref>

In a double-blind, randomized, placebo-controlled trial done by Division of Cardiovascular Medicine, [[Vanderbilt University Medical Center]], Nashville, Tennessee, 240 adults were given either theaflavin-enriched green tea extract in form of 375mg capsule daily or a placebo. After 12 weeks, patients in the tea extract group had significantly less low-density lipoprotein cholesterol (LDL-C) and total cholesterol (16.4% and 11.3% lower than baseline, p<0.01) than the placebo group. The author concluded that theaflavin-enriched green tea extract can be used together with other dietary approaches to reduce LDL-C. 

A study published in the January, 2005 edition of the American Journal of Clinical Nutrition concluded "Daily consumption of tea containing 690 mg catechins for 12 wk reduced body fat, which suggests that the ingestion of catechins might be useful in the prevention and improvement of lifestyle-related diseases, mainly obesity." <ref>http://www.ajcn.org/cgi/content/abstract/81/1/122</ref>

Antioxidants in green tea may prevent and reduce the severity of rheumatoid arthritis, according to a [[Case Western Reserve University]] School of Medicine study published in the April 13 2005 issue of the [[Proceedings of the National Academy of Sciences]]. The study examined the effects of green tea polyphenols on collagen-induced arthritis in mice, which is similar to rheumatoid arthritis in humans. In each of three different study groups, the mice given the green tea polyphenols were significantly less likely to develop arthritis. Of the 18 mice that received the green tea, only eight (44 percent) developed arthritis. Among the 18 mice that did not receive the green tea, all but one (94 percent) developed arthritis. In addition, researchers noted that the eight arthritic mice that received the green tea polyphenols developed less severe forms of arthritis. 

A German study found that an extract of green tea and hot water (filtered), applied externally to the skin for 10 minutes, three times a day could help people with skin damaged from radiation therapy (after 16-22 days). <ref>http://www.cbsnews.com/stories/2006/12/04/earlyshow/contributors/emilysenay/main2224186.shtml</ref>

A study published in the December 1999 American Journal of Clinical Nutrition found that "Green tea has thermogenic properties and promotes fat oxidation beyond that explained by its caffeine content per se. The green tea extract may play a role in the control of body composition via sympathetic activation of thermogenesis, fat oxidation, or both."<ref>http://www.ajcn.org/cgi/content/abstract/70/6/1040</ref>

In lab tests, [[EGCG]], found in green tea, was found to prevent [[HIV]] from attacking T-Cells. However, it is not known if this has any effect on humans yet. <ref>http://www.webmd.com/content/article/122/114877.htm</ref>

A study in the August, 2003 issue of a new potential application of Cellular and Molecular Life Sciences found that "a new potential application of (–)-epigallocatechin-3-gallate [a component of green tea] in prevention or treatment of inflammatory processes is suggested" <ref>http://www.springerlink.com/content/xqa0w01wd87q1nca/</ref>

==See also==
{{Commonscat|Green tea}}
* [[Chinese tea culture]]
* [[Japanese tea ceremony]]
* [[Potential effects of tea on health]]
* [[Reactive oxygen species]]
* [[Yellow tea]]

==References==
<!-- ----------------------------------------------------------
 See http://en.wikipedia.org/wiki/Wikipedia:Footnotes for a
 discussion of different citation methods and how to generate
 footnotes using the <ref>, </ref> and <reference /> tags
----------------------------------------------------------- -->
<div class="references-small">
<references />
</div>
* {{cite book
| author=Master Lam Kam Cheun et al
| year = 2002
| title = The way of tea
| publisher = Gaia Books
| ISBN 1-85675-143-0
}}

==External links==
* [http://www.cancer.org/docroot/ETO/content/ETO_5_3X_Green_Tea.asp?sitearea=ETO American Cancer Society] - Information about green tea
* [http://www.jin.ne.jp/ogasawara/english/intro.htm An Introduction to Tea Ceremony]
* [http://infohost.nmt.edu/~armiller/japanese/tea.htm Types of Japanese Tea]

===Press coverage===
* [http://www.cancer.gov/cancertopics/factsheet/tea-and-cancer-prevention ''Tea and Cancer Prevention'' from The National Cancer Institute]
* [http://www.webmd.com/content/chat_transcripts/2/110457 An interview with Thomas Gasiewicz on green tea and cancer]
* [http://www.urmc.rochester.edu/pr/news/story.cfm?id=788 Scientists on Trail of Dioxin Pinpoint How Green Tea Protects Against Cancer]
* [http://www.webmd.com/content/article/18/1678_50885 Green Tea May Aid Liver Disease Patients]
* [http://www.physorg.com/news62928428.html  Tea: the New Anti-Aging Beverage?]
* [http://www.medicalnewstoday.com/medicalnews.php?newsid=23018 Tea may help prevent diabetes and cataracts]
* [http://news.bbc.co.uk/2/hi/health/3125469.stm Green tea 'can block cancer']
* [http://www.nlm.nih.gov/hmd/teapot/medical.html Green Tea's Medical Resurgence]
* [http://www.pdrhealth.com/drug_info/nmdrugprofiles/nutsupdrugs/gre_0319.shtml Green Tea Catechins]
* [http://www.umm.edu/altmed/ConsHerbs/GreenTeach.html Green Tea (an overview from the University of Maryland Medical Center)]
* [http://www.worldhealth.net/p/257,6484.html Green Tea a Performance-enhancing Drug]
* [http://aidsmeds.com/articles/1667_11621.shtml ''Green Tea for HIV?'' from AIDSmeds.com]

[[Category:Japanese tea]]
[[Category:Chinese tea]]
[[Category:Green tea|*]]
[[Category:Antioxidants|G]]
[[Category:Tea culture]]