Green Tea Extract Benefits: Kills Cancer Cells, Improves Blood Sugar Control, Slows Alzheimer's Disease, Improves Cardiovascular Disease, Reduces LDL Cholesterol, Blocks Formation Of Plaques In Atherosclerosis, Improves Peripheral Neuropathy, Lowers Inflammation, With EGCG (Epigallocatechin-3-Gallate) Catechin Polyphenols
This page summarizes dozens of scientific studies from medical journals
describing the health benefits of green tea. Read why it is the
most important herbal supplement you can add to your daily diet.
We believe that green tea (or the concentrated extracts, taken as a daily supplement in capsule or tablet form) is one of the most healthful aids for people suffering from Level 2's inflammatory conditions, or Level 3's overt diseases. The active ingredient in green tea has been discovered to be a polyphenol, also called a catechin, with the hard to pronounce name epigallocatechin-3-gallate or EGCG.
Thousands of recent scientific studies have shown the effectiveness of green tea and its EGCG active ingredient in helping to improve diabetic blood sugar metabolism, reduce insulin resistance, reduce bad cholesterol levels, improvehypertension, and significantly to help kill cancer cells. Some research appears to support taking green tea to help other conditions such as peripheral neuropathy and Alzheimer's.
The benefits of green tea or its EGCG active ingredient appear to fall into several important areas, each of which seems to mimick or imitate the basic functionality of powerful (and expensive) patented drugs:
1. Heart Disease ― EGCG reduces the incidence of cardiovascular diseases. This is apparently due to the ability of the active ingredient of green tea to slow or inhibit the rate of proliferation of vascular smooth muscle cells, which would result in the accumulation of arterial plaques, thus eventually creating atherosclerosis.
Catechins inhibit angiotensin II-induced vascular smooth muscle cell proliferation via mitogen-activated protein kinase pathway. Catechins, components of green tea, reduce the incidence of cardiovascular diseases such as atherosclerosis. Angiotensin II (Ang II) is highly implicated in the proliferation of vascular smooth muscle cells (VSMC), resulting in atherosclerosis. The acting mechanisms of the catechins remain to be defined in the proliferation of VSMC induced by Ang II. Here we report that catechin, epicatechin (EC), epicatechingallate (ECG) or epigallocatechingallate (EGCG) significantly inhibits the Ang II-induced [3H]thymidine incorporation into the primary cultured rat aortic VSMC. Ang II increases the phosphorylation of the extracellular signal-regulated protein kinase 1/2 (ERK 1/2), c-jun-N-terminal kinase 1/2 (JNK 1/2), or p38 mitogen-activated protein kinases (MAPKs) and mRNA expression of c-jun and c-fos. The EGCG pretreatment inhibits the Ang II-induced phosphorylation of ERK 1/2, JNK 1/2, or p38 MAPK, and the expression of c-jun or c-fos mRNA. U0126, a MEK inhibitor, SP600125, a JNK inhibitor, or SB203580, a p38 inhibitor, attenuates the Ang II-induced [3H]thymidine incorporation into the VSMC. In conclusion, catechins inhibit the Ang II-stimulated VSMC proliferation via the inhibition of the Ang II-stimulated activation of MAPK and activator protein-1 signaling pathways. The antiproliferative effect of catechins may be associated with the reduced risk of cardiovascular diseases by the intake of green tea. Catechins [i.e. green or black teas] may be useful in the development of prevention and therapeutics of vascular diseases.Department of Physiology, School of Medicine, Kyungpook National University, Daegu 700-422, Korea. Exp Mol Med. 2006 Oct 31;38(5):525-34.
2. Diabetes ― EGCG mimicks some anti-diabetic drugs like metformin or pioglitazide, in its simulation of many of the roles of insulin in stimulating glucose removal or uptake, without the problems due to insulin's stimulation of lipid (cholesterol) production, triglycerides, and higher cell growth rates. These processes improve or reduce insulin resistance, and reduce excessive production of lipids or cholesterol that would have resulted from high levels of insulin. This activity seems to be accompanied by few if any undesirable side effects.
Epigallocatechin gallate, a constituent of green tea, represses hepatic glucose production. Herbs have been used for medicinal purposes, including the treatment of diabetes, for centuries. Plants containing flavonoids are used to treat diabetes in Indian medicine and the green tea flavonoid, epigallocatechin gallate (EGCG), is reported to have glucose-lowering effects in animals. We show here that the regulation of hepatic glucose production is decreased by EGCG. Furthermore, like insulin, EGCG increases tyrosine phosphorylation of the insulin receptor and insulin receptor substrate-1 (IRS-1), and it reduces phosphoenolpyruvate carboxykinase gene expression in a phosphoinositide 3-kinase-dependent manner. EGCG also mimics insulin by increasing phosphoinositide 3-kinase, mitogen-activated protein kinase, and p70(s6k) activity. EGCG differs from insulin, however, in that it affects several insulin-activated kinases with slower kinetics. Furthermore, EGCG regulates genes that encode gluconeogenic enzymes and protein-tyrosine phosphorylation by modulating the redox state of the cell. These results demonstrate that changes in the redox state may have beneficial effects for the treatment of diabetes and suggest a potential role for EGCG, or derivatives, as an antidiabetic agent. Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-0615, USA. J Biol Chem. 2002 Sep 20;277(38):34933-40. Epub 2002 Jul 12.
Epigallocatechin gallate supplementation alleviates diabetes in rodents. As the prevalence of type 2 diabetes mellitus is increasing at an alarming rate, effective nutritional and exercise strategies for the prevention of this disease are required. Specific dietary components with antidiabetic efficacy could be one aspect of these strategies. This study investigated the antidiabetic effects of the most abundant green tea catechin, epigallocatechin gallate (EGCG, TEAVIGO), in rodent models of type 2 diabetes mellitus and H4IIE rat hepatoma cells. We assessed glucose and insulin tolerance in db/db mice and ZDF rats after they ingested EGCG. Using gene microarray and real-time quantitative RT-PCR we investigated the effect of EGCG on gene expression in H4IIE rat hepatoma cells as well as in liver and adipose tissue of db/db mice. EGCG improved oral glucose tolerance and blood glucose in food-deprived rats in a dose-dependent manner. Plasma concentrations of triacylglycerol were reduced and glucose-stimulated insulin secretion was enhanced. In H4IIE cells, EGCG downregulated genes involved in gluconeogenesis and the synthesis of fatty acids, triacylgycerol, and cholesterol. EGCG decreased the mRNA expression of phosphoenolpyruvate carboxykinase in H4IIE cells as well as in liver and adipose tissue of db/db mice. Glucokinase mRNA expression was upregulated in the liver of db/db mice in a dose-dependent manner. This study shows that EGCG beneficially modifies glucose and lipid metabolism in H4IIE cells and markedly enhances glucose tolerance in diabetic rodents.Dietary supplementation with EGCG could potentially contribute to nutritional strategies for the prevention and treatment of type 2 diabetes mellitus. DSM Nutritional Products Ltd, Department of Human Nutrition and Health, CH-4002 Basel, Switzerland. J Nutr. 2006 Oct;136(10):2512-8.
3. Cancer Drug Comparisons ― EGCG mimicks or actually improves the ability of some anti-cancer drugs to work, by increasing the rate at which tumor cells die without affecting normal cells, and by slowing the growth of tumor blood supplying capillaries and viens, therefore starving the tumor of needed nutrients.
Comparison of potential chemotherapeutic agents, 5-fluoruracil, green tea, and thymoquinone on colon cancer cells. Antioxidants have been found to be quite successful in deterring certain disease processes for years, especially cancer. Antioxidants protect the body by neutralizing the free radicals and donating one of their own electrons, thus ending the scavenger reaction. Epigallocatechin-3-gallate (EGCG), the most abundant catechin found in green tea, is a valuable scavenger of reactive oxygen species in vitro as well as in vivo. Thymoquinone (TQ), a major active component of black seed (Nigella sativa), is also known for its powerful scavenger abilities as an inhibitor of oxidative stress and has been utilized in the Middle East for centuries for healing properties. These two potent antioxidants when compared to the chemotherapeutic drug of choice, 5-fluorouracil (5-FU), have demonstrated incredible chemotherapeutic responses to the SW-626 cell line. The objective of this study was to evaluate and compare the effects of SW-626 colon cancer cells after a 24, 48, and 72 hour incubation periods with low, medium, and high doses of EGCG, TQ, and 5-FU. Cell viability, cell number, cellular morphology, and cellular metabolism were compared for the control and treatment groups. The results of this study evidenced a similar significant decrease in cell number as early as 24 hours in the groups treated with TQ and EGCG compared to 5-FU. Increases in cellular damage were evident after 24, 48, and 72 hours and in all treated groups compared with the control. Reduced cell numbers in the treated groups suggests the possibility that TQ and EGCG may have similar chemotherapeutic effects on cancer cells as 5-FU. School of Health Related Professions, University of Mississippi Medical Center Jackson, Mississippi 39216, USA. Biomed Sci Instrum. 2006;42:350-6.
Green tea extract and (-)-epigallocatechin-3-gallate inhibit hypoxia- and serum-induced HIF-1alpha protein accumulation and VEGF expression in human cervical carcinoma and hepatoma cells. Green tea extract and its major component (-)-epigallocatechin-3-gallate (EGCG) exhibit antiangiogenic activities in various experimental tumor models. A growing body of evidence has established that hypoxia-inducible factor-1alpha (HIF-1alpha) and its downstream target, vascular endothelial growth factor (VEGF), play a critical role in tumor angiogenesis. In this study, we investigated the effect of green tea extract and EGCG on HIF-1alpha and VEGF expression in human cervical carcinoma (HeLa) and hepatoma (HepG2) cells. Our results showed that green tea extract and EGCG significantly inhibited hypoxia- and serum-induced HIF-1alpha protein accumulation in these cancer cells but had no effects on HIF-1alpha mRNA expression. Suppression of HIF-1alpha protein by green tea extract and EGCG also resulted in a drastic decrease in VEGF expression at both mRNA and protein levels. The mechanisms of green tea extract and EGCG inhibition of hypoxia-induced HIF-1alpha protein accumulation seem to involve the blocking of both phosphatidylinositol 3-kinase/Akt and extracellular signal-regulated kinase 1/2 signaling pathways and the enhancing of HIF-1alpha protein degradation through the proteasome system. In addition, green tea extract and EGCG inhibited serum-induced HIF-1alpha protein and VEGF expression by interfering with the phosphatidylinositol 3-kinase/Akt/mammalian target of rapamycin signaling pathways, which play a crucial role in the protein translational machinery cascade. Functionally, green tea extract and EGCG abolished both chemoattractant- and hypoxia-stimulated HeLa cell migration. Our data suggested that HIF-1alpha/VEGF function as therapeutic target for green tea extract and EGCG in the context of cancer chemoprevention and anticancer therapy. Division of Surgical, Therapeutic and Bioengineering Sciences, Center for Craniofacial Molecular Biology, University of Southern California School of Dentistry, Health Sciences Campus, 2250 Alcazar Street, CSA103, Los Angeles, CA 90033, USA. Mol Cancer Ther. 2006 May;5(5):1227-38.
4. Alzheimer's Disease ― EGCG is being tested for major applications in the treatment of Alzheimer's disease. Evidently the flavinols and phenolic compounds in teas inhibit the formation of the fibroid beta-amyloids in the development of Alzheimer's, thus lowering the severity or slowing the onset of the disease.
Neuroprotective effects of green and black teas and their catechin gallate esters against beta-amyloid-induced toxicity. Teas represent a large family of plants containing high amounts of polyphenols that may confer health benefits in various diseases. Recently, it has been hypothesized that tea consumption may also reduce the risk of age-related neurodegenerative pathologies. Considering the deleterious role of beta-amyloid (Abeta) in the aetiology of Alzheimer's disease (AD), we investigated green and black tea extracts and flavan-3-ols (present as monomers and dimers in green and black forms, respectively) against toxicity induced by Abeta-derived peptides using primary cultures of rat hippocampal cells as model. Both green and black tea extracts (5-25 microg/mL) displayed neuroprotective action against Abeta toxicity. These effects were shared by gallic acid (1-20 microm), epicatechin gallate (ECG; 1-20 microM) and epigallocatechin gallate (EGCG; 1-10 microM), the former being the most potent flavan-3-ol. In contrast, epicatechin and epigallocatechin were ineffective in the same range of concentrations. Moreover, only tea flavan-3-ol gallate esters (i.e. ECG, EGCG) and gallic acid inhibited apoptotic events induced by Abeta(25-35). Interestingly, EGCG and gallic acid inhibited Abeta aggregation and/or the formation of Abeta-derived diffusible neurotoxin ligands. Taken together, these results indicate that the catechin gallates (through the galloyl moiety) contribute to the neuroprotective effects of both green and black teas. Moreover, the protective effect of EGCG is likely to be associated, at least in part, with its inhibitory action on Abeta fibrils/oligomers formation. These data also support the hypothesis that not only green but also black teas may reduce age-related neurodegenerative diseases, such as AD.Douglas Hospital Research Centre, Department of Psychiatry, McGill University, 6875 Blvd LaSalle, Verdun, Quebec, Canada H4H 1R3. Eur J Neurosci. 2006 Jan;23(1):55-64.
5. Cancer COX-2 Treatment ― Green Tea's EGCG mimicks the effect of some NSAIDs (non-steroidal anti-inflammatory drugs) in the inhibition of COX-2 (cyclooxygenase 2), which is one of the major factors implicated in the growth of many cancerous tumors.
Green tea polyphenol (-)-epigallocatechin-3-gallate inhibits cyclooxygenase-2 expression in colon carcinogenesis. Tea, one of the most widely consumed beverages worldwide, has been shown to have anti-cancer activity in various cancers including colon cancer. It has been demonstrated that overexpression of the inducible isoform of cyclooxygenase (COX-2) occurs during colon tumorigenesis and inhibition of COX-2 by non-steroidal anti-inflammatory drugs (NSAIDs) is chemopreventive. To determine whether the anti-cancer effect associated with green tea impacted COX-2 expression levels, human colorectal cancer cell lines HT-29 and HCA-7, were treated with (-)-epigallocatechin-3-gallate (EGCG), the most abundant and effective polyphenol of green tea. EGCG significantly inhibited constitutive COX-2 mRNA and protein overexpression. The inhibitory effects of EGCG on signaling pathways controlling COX-2 expression were examined. We observed that EGCG down regulated the ERK1/2 and Akt pathways in colon cancer cells. The effect of EGCG on COX-2 expression resulted in decreased COX-2 promoter activity via inhibition of nuclear factor kappaB (NF-kappaB) activation. EGCG also promoted rapid mRNA decay mediated through the COX-2 3'untranslated region (3'UTR). In conclusion, these data suggest that inhibition of COX-2 is a mechanism for the anti-proliferative effect of green tea and emphasizes the role that dietary factors have as anti-cancer agents.Department of Pathology and Microbiology, School of Medicine, The University of South Carolina, and South Carolina Cancer Center, Columbia, South Carolina 29203, USA. Mol Carcinog. 2006 May;45(5):309-19.
6. Deaths Due to Strokes ― One of the strongest benefits to consuming green tea appears to be the prevention of strokes. A recent 11 year study of 40,000 Japanese men and women aged 40-79 showed high correlations of stroke and cardiovascular disease prevention, with drinking from 1 to 5 cups of green tea per day. Supplementation with stronger dose of the extracted concentrates of EGCG was not studied in this report.
Green tea consumption and mortality due to cardiovascular disease, cancer, and all causes in Japan: the Ohsaki study. CONTEXT: Green tea polyphenols have been extensively studied as cardiovascular disease and cancer chemopreventive agents in vitro and in animal studies. However, the effects of green tea consumption in humans remain unclear. OBJECTIVE: To investigate the associations between green tea consumption and all-cause and cause-specific mortality. DESIGN, SETTING, AND PARTICIPANTS: The Ohsaki National Health Insurance Cohort Study, a population-based, prospective cohort study initiated in 1994 among 40,530 Japanese adults aged 40 to 79 years without history of stroke, coronary heart disease, or cancer at baseline. Participants were followed up for up to 11 years (1995-2005) for all-cause mortality and for up to 7 years (1995-2001) for cause-specific mortality. MAIN OUTCOME MEASURES: Mortality due to cardiovascular disease, cancer, and all causes. RESULTS: Over 11 years of follow-up (follow-up rate, 86.1%), 4209 participants died, and over 7 years of follow-up (follow-up rate, 89.6%), 892 participants died of cardiovascular disease and 1134 participants died of cancer. Green tea consumption was inversely associated with mortality due to all causes and due to cardiovascular disease. The inverse association with all-cause mortality was stronger in women (P = .03 for interaction with sex). In men, the multivariate hazard ratios of mortality due to all causes associated with different green tea consumption frequencies were 1.00 (reference) for less than 1 cup/d, 0.93 (95% confidence interval [CI], 0.83-1.05) for 1 to 2 cups/d, 0.95 (95% CI, 0.85-1.06) for 3 to 4 cups/d, and 0.88 (95% CI, 0.79-0.98) for 5 or more cups/d, respectively (P = .03 for trend). The corresponding data for women were 1.00, 0.98 (95% CI, 0.84-1.15), 0.82 (95% CI, 0.70-0.95), and 0.77 (95% CI, 0.67-0.89), respectively (P<.001 for trend). The inverse association with cardiovascular disease mortality was stronger than that with all-cause mortality. This inverse association was also stronger in women (P = .08 for interaction with sex). In women, the multivariate hazard ratios of cardiovascular disease mortality across increasing green tea consumption categories were 1.00, 0.84 (95% CI, 0.63-1.12), 0.69 (95% CI, 0.52-0.93), and 0.69 (95% CI, 0.53-0.90), respectively (P = .004 for trend). Among the types of cardiovascular disease mortality, the strongest inverse association was observed for stroke mortality. In contrast, the hazard ratios of cancer mortality were not significantly different from 1.00 in all green tea categories compared with the lowest-consumption category. CONCLUSION: Green tea consumption is associated with reduced mortality due to all causes and due to cardiovascular disease but not with reduced mortality due to cancer. [Editorial Note: This study only looked at drinking up to 5 cups/day of the beverage, not at supplementation with concentrated extracts of the active ingredient EGCG which could equal 30 or more cups of the drink. Supplementation of the purified EGCG extract has in fact proven to reduce cancer risks in many studies.] Division of Epidemiology, Department of Public Health and Forensic Medicine, Tohoku University Graduate School of Medicine, Sendai, Japan. firstname.lastname@example.org. Mol Carcinog. 2006 May;45(5):309-19. JAMA. 2006 Sep 13;296(10):1255-65.
A study on the association between tea consumption and stroke OBJECTIVE: The aim of the study was to investigate the association between tea consumption and stroke. METHODS: A cross sectional study was conducted in autumn, 1998. The subjects were from 12 provinces in China. 15 groups of populations were selected by cluster randomized sampling and each group had about 1000 persons, aged from 35 to 60 years old. 14 212 subjects had complete data for analysis. Data regarding tea drinking would include drinking status, dose and type of teas. Logistic regression was used to analyze the association between tea consumption and stroke. RESULTS: There was a strong inverse correlation between tea drinking and stroke after adjusting other risk factors of stroke (P < 0.05). The odds ratio (OR) of stroke was 0.60 [95% confidence interval (CI): 0.42 - 0.85] for subjects who drank tea compared to those who did not. Increased amount of tea consumption per month was associated with decreased stroke prevalence. The association for tea consumption over 150 gram per month and stroke was statistically significant (P < 0.05) with an OR value of 0.56 (95% CI: 0.36 - 0.89). Analytical results indicated that the OR value was 0.24 (95% CI: 0.06 - 1.01) for black tea and other tea (P = 0.05). The OR value was 0.35 (95% CI: 0.18 - 0.72) for green tea (P < 0.01), and 0.75 (95% CI: 0.51 - 1.11) for jasmine tea (P > 0.05). CONCLUSION: Tea drinking was independently associated with prevalence of stroke which might play a role in the prevention of the disease.Department of Epidemiology, Cardiovascular Institute and Fu Wai Hospital, Chinese Academy of Medical Sciences, Beijing 100037, China. Zhonghua Liu Xing Bing Xue Za Zhi. 2004 Aug;25(8):666-70.
IGF-I activity may be a key determinant of stroke risk--a cautionary lesson for vegans.IGF-I acts on vascular endothelium to activate nitric oxide synthase, thereby promoting vascular health; there is reason to believe that this protection is especially crucial to the cerebral vasculature, helping to ward off thrombotic strokes. IGF-I may also promote the structural integrity of cerebral arteries, thereby offering protection from hemorrhagic stroke. These considerations may help to explain why tallness is associated with low stroke risk, whereas growth hormone deficiency increases stroke risk--and why age-adjusted stroke mortality has been exceptionally high in rural Asians eating quasi-vegan diets, but has been declining steadily in Asia as diets have become progressively higher in animal products. There is good reason to suspect that low-fat vegan diets tend to down-regulate systemic IGF-I activity; this effect would be expected to increase stroke risk in vegans. Furthermore, epidemiology suggests that low serum cholesterol, and possibly also a low dietary intake of saturated fat--both characteristic of those adopting low-fat vegan diets--may also increase stroke risk. Vegans are thus well advised to adopt practical countermeasures to minimize stroke risk--the most definitive of which may be salt restriction. A high potassium intake, aerobic exercise training, whole grains, moderate alcohol consumption, low-dose aspirin, statin or policosanol therapy, green tea, and supplementation with fish oil, taurine, arginine, and B vitamins--as well as pharmacotherapy of hypertension if warranted--are other practical measures for lowering stroke risk. Although low-fat vegan diets may markedly reduce risk for coronary disease, diabetes, and many common types of cancer, an increased risk for stroke may represent an 'Achilles heel'. Nonetheless, vegans have the potential to achieve a truly exceptional 'healthspan' if they face this problem forthrightly by restricting salt intake and taking other practical measures that promote cerebrovascular health. Pantox Laboratories, San Diego, California 92109, USA. Med Hypotheses. 2003 Sep;61(3):323-34.
The list of diseases that may be improved by drinking Green Tea or taking concentrated green tea extract tablets keeps growing. Every month, more and more studies are published in scientific journals around the world. To read the latest at the U.S. National Library of Medicine (part of the enormous National Institutes of Health online health abstract database), go to this page for 2,300+ studies about Green Tea and this page for 1,180+ studies about Epigallocatechin-3-Gallate or 1,120+ studies about EGCG.
Here is a brief look at just a few of the hundreds of health improvement issues reported to be associated with taking Green Tea in over 2,000 recent scientific studies:
While research continues, we believe that taking several daily capsules of green tea concentrates and extracts would be wise for many of us who suffer from the degenerative conditions common to modern man. (See the links above, in this paragraph to read a few of the many scientific studies on green tea and common diseases.)
General Information On Green Teas Around The World
Green Tea - Green tea is a "true" tea (i.e. Camellia sinensis) that has undergone minimal oxidation during processing. Green tea is popular in mainland China, Taiwan, Hong Kong, Japan, Middle East and has recently become more popular in the West, which traditionally drinks black tea (a "true" tea made from leaves more heavily oxidized than the white, green, and oolong varieties).
Proponents of green tea note that its medicinal benefits have been described for over 1000 years. The Kissa Yojoki, or 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 disease, preventing 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.
In more recent times, many studies have investigated a link between the consumption of green tea and a lower incidence of a range of cancers in populations, with mixed results. Green tea has been claimed to be useful for:
Green Tea contains high levels of a natural chemical known as EGCG (epigallocatechin-3-gallate). This unique substance works in many ways to reduce the ability of cancer cells to proliferate or survive in the human body. An exciting scientific study by the Mayo Clinic in 2003 (published online on March 2, 2004) demonstrated the power of EGCG to kill at least some types leukemia cancer cells:
History of Tea in Asia
The Chinese are said to be the first ones to discover tea, and in China the most varieties of tea are found. Chinese legend says that one day, an Emperor was boiling some water on a fire, and a sudden wind swept by several small trees nearby. During this great gust of wind, a handful of leaves from the trees were blown off their branches, and landed in the emperor's kettle. He tasted the strange liquid that formed and was delighted at what he found. Have your say. The result was tea. Currently there are many different varieties of tea in the world from the Camellia Sinensis plant.
The first of the less processed teas were white teas, whilst further processing created green teas that could be stored for longer periods of time. During the Tang Dynasty, wild tea was gathered and then processed. Processing involved steaming the tea on a bamboo tray, grinding the tea into a fine pulp called tea mud and then placing this mud into moulds. The tea was then pressed and left to harden. It was then transferred out of the mould, dried in the sun, and baked to prevent rotting. This is very different to how green tea is processed today; whilst this practice of grinding tea continued into the Sung Dynasty by the Yuan Dynasty, it had all but vanished in favour of leaf teas. Compressed raw teas are still made in Yunnan and a few other provinces, they are very popular and are discussed in the Pu-erh tea article, however these teas are classified differently because they undergo a period of aging.
Tea has played a significant role in the culture of East Asia for centuries as a staple beverage, a curative and a symbol of status. It is not surprising its discovery is ascribed to religious or royal origins. Even the earliest texts discuss the health benefits of tea. One of the earliest known references in Japan is a 9th century text. It was the Heian Period (A.D. 794-1185) of peace, prosperity, and openness to ideas and cultures particularly from China. Many aspects of Chinese culture, Chinese writing system, and religion were introduced during this period including parts of the modern Japanese writing systems.
Zhejiang is home to the most famous of all teas, Xi Hu Longjing, as well as many other high quality green teas.
Longjing - A Chinese famous tea from Hangzhou, in fact the most famous tea. 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 and hence not authentic Longjing. It is also known as Dragon Well.
Hui Ming - Named after a temple in Zhejiang.
Long Ding - A tea from Kaihua County known as Dragon Mountain.
Hua Ding - A tea from Tiantai County and named after a peak in the Tiantai mountain range.
Qing Ding - A tea from Tian Mu, also known as Green Top.
Gunpowder - A popular tea also known as zhuch�. It originated in Zhejiang but is now grown elsewhere in China.
Yu Lu - A steamed tea known as Jade Dew made in the Japanese style
Xin Yang Mao Jian - A Chinese famous tea also known as Green Tip.
Bi Luo Chun - A 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 - A tea from Nanjing.
Yun Wu - A tea also known as Cloud and Mist. Chun Mee - Originally a tea in the shape of eyebrows from Jiangxi, it is now grown elsewhere.
Anhui Province is home to three Chinese famous teas, and some not so hot teas, too.
Da Fang - A tea from Mount Huangshan also known as Big Square
Huangshan Mao Feng - A Chinese famous tea tea from Mount Huangshan.
Lu An Guapian - A Chinese famous tea also known as Melon Seed.
Hou Kui - A Chinese famous tea also known as Monkey tea.
Tun Lu - A tea from Tunxi District.
Huo Qing - A tea from Jing County, also known as Fire Green.
Hyson - A mediocre quality tea from many provinces, an early harvested tea.
Green tea (ryokucha) is so ubiquitous in Japan that it is more commonly known as "tea" (ocha) and even "Japanese tea" (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.
Gyokuro Green Teas
Gyokuro ("jewel dew") - Gyokuro tea is generally sweet and delicate in flavor. Selected from a grade of green tea known as tencha, Gyokuro is regarded as the highest grade of tea made in Japan. Gyokuro's name refers to the pale green color of the infusion.
Matcha ("rubbed tea") - Used primarily in the tea ceremony. Matcha comes from gyokuro leaves that have been steamed and dried. The tea bushes are shaded from sunlight for 3 weeks before harvesting, producing amino acids that sweeten the taste. All stems and veins are removed from the leaves. The pure dried leaves (tencha) are then stone ground into a super fine powder that is the consistency of talc. Most high quality matcha comes from the Uji Tawara area, the premier matcha producing region in Japan. Matcha is also a popular flavour of ice cream and other sweets in Japan.
Mecha Green Teas
Mecha ("bud tea") - The name of this tea derives from the early leaf buds needed to make this special green tea. Mecha is harvested in spring and made as rolled leaf teas that are graded somewhere between Gyokuro and Sencha in quality. Mecha are made from a collection of leaf buds and tips of the early crops.
Sencha Green Teas
Sencha ("roasted tea") - The most common type of green tea in Japan. It is made from the young leaves of uncovered plants. Over three quarters of all tea produced in Japanese tea gardens is sencha. The earliest season (first month's sencha harvest) is called shincha. Later harvests of sencha have more astringent qualities, a more robust flavor and generally less aroma.
Shincha ("new tea") - A newly harvested, lightly steamed sencha. It is aromatic but highly perishable, lasting for only about 3 months. Shincha is available in April in the south of Japan, and prized for its high vitamin content, sweetness, and superior flavor.
Genmaicha ("roasted rice tea") - A blend of bancha green tea and genmai (roasted rice grain). The flavor is a m�lange of these two ingredients. The roasted aroma of genmai teas has the effect of lightening the bitterness of the lower grade sencha. The proportioning of tea to rice is important, the more aromatic genmai teas have a higher amount of rice.
Kabusecha ("covered tea") - Unlike most sencha cultivated in unshaded gardens exposed to direct sunlight, kabusecha sencha requires shading tea prior to harvest. Kabusecha sencha has a mellower flavor and more subtle color than sencha grown in direct sunlight.
Kamairicha ("pan fired tea") - Kamairi teas do not undergo the usual steam treatments. After a short withering, they are fired in hot iron pans of up to 300�C with repeated agitation to prevent charring. The different rolling techniques used produce teas of different leaf form. Kamairicha is processed as a pelleted or flat leaf.
Bancha Green Teas
Bancha ("number or common tea") - A class of sencha harvested as a second flush tea between summer and autumn. While lacking the delicate sweetness of quality sencha it is respected for its well-defined character, vivid yellow colors and refreshing and deep flavors. Bancha's meaning references the coarser grades and heavier, late season crop from which this full-flavoured tea is made. It is milder, cheaper and contains less caffeine than other varieties.
Hojicha ("roasted tea") - A pan-fried or oven roasted green tea commonly found in teashops throughout Japan. Both bancha and kukicha are used to make hojicha grades. Hojicha tends to be a more aromatic tea. It holds very little astringency, has a distinctively clear red appearance and is lower in caffeine.
Kukicha Green Teas
Kukicha ("stalk tea") - A tea made from stalks produced by harvesting one bud and three leaves. The combined stalk fractions and emerald leaf of gyokuro and sencha blends are then processed. Kukicha is known for its light flavor and fresh green aroma with a very light yellow-green color. The best kukicha has a flavor considered to be as good as highest quality sencha. It contains only a tenth of the caffeine of leaf tea and its flavor is commonly compared to oolong teas.
Other Green Teas
Mediocre quality tea is often produced to resemble the lower grades of Chinese or Japanese tea in appearance outside those countries, however there are some notable teas grown outside China and Japan.
The U.S. Food and Drug Administration (FDA) has rejected claims of health benefits for green tea.
In a 2006 study published in The American Journal of Clinical Nutrition (Vol. 83, pp 355-361) showed that elderly Japanese people who drank more than 2 cups of green tea a day had a 50 percent lower chance of having cognitive impairment than those who drank less or who consumed other tested beverages. The high amount of catechins found in green tea is thought to be the reason.
In May 2006 researchers at 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 polyphenols and other antioxidants. These compounds may work in several ways to improve cardiovascular health, including preventing blood platelets from sticking together 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 kind), which, in turn, can reduce the buildup of plaque in arteries, the researchers wrote.
When green tea should be avoided
Avoid drinking green tea or at least talk to your doctor before taking green tea if you have:
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