All true teas-as distinct from herbal and flower infusions, which afficiandos call tisanes-are made from the leaves of a magnolia-related evergreen tree with the botanical name of Camellia sinensis. Although reaching a height of 30 feet in the wild, on tea plantations (called gardens or estates), the plant is kept as a shrub, constantly pruned to a height of about 3 feet to encourage new growth and for convenient picking.

Tea plants grow only in warm climates but can flourish at altitudes ranging from sea level to 7,000 feet. The best teas, however, are produced by plants grown at higher altitudes where the leaves mature more slowly and yield a richer flavor. Depending upon the altitude, a new tea plant may take from 2 ½ to 5 years to be ready for commercial picking, but once productive, it can provide tea leaves for close to a century.

Tea plants produce abundant foliage, a camellia-like flower, and a berry, but only the smallest and youngest leaves are picked for tea-the two leaves and bud at the top of each young shoot. The growth of new shoots, called a flush, can occur every week at lower altitudes but takes several weeks at higher ones. The new leaves are picked by hand by "tea pluckers," the best of whom can harvest 40 pounds per day, enough to make 10 pounds of tea.

All tea plants belong to the same species-Camellia sinensis-, but local growing conditions (altitude, climate, soils, etc.) vary, resulting in a multitude of distinctive leaves. The way the leaves are processed, however, is even more important in developing the individual characteristics of the three predominant types of tea: green, black and oolong.

Green tea is the least processed and thus provides the most antioxidant polyphenols, notably a catechin called epigallocatechin-3-gallate (EGCG), which is believed to be responsible for most of the health benefits linked to green tea. Green tea is made by briefly steaming the just harvested leaves, rendering them soft and pliable and preventing them from fermenting or changing color. After steaming, the leaves are rolled, then spread out and "fired" (dried with hot air or pan-fried in a wok) until they are crisp. The resulting greenish-yellow tea has a green, slightly astringent flavor close to the taste of the fresh leaf.

In black tea production, the leaves are first spread on withering racks and air-blown, which removes about one-third of their moisture and renders them soft and pliable. Next, they are rolled to break their cell walls, releasing the juices essential to fermentation. Once again, they are spread out and kept under high humidity to promote fermentation, which turns the leaves a dark coppery color and develops black tea's authoritative flavor. Finally, the leaves are "fired," producing a brownish black tea whose immersion in hot water gives a reddish-brown brew with a stronger flavor than green or oolong teas.

Oolong tea, which is made from leaves that are partially fermented before being fired, falls midway between green and black teas. Oolong is a greenish-brown tea whose flavor, color and aroma are richer than that of green tea, but more delicate than that of black.

Green tea has always been, and remains today, the most popular type of tea from China where most historians and botanists believe the tea plant originated throughout all of Asia. Why is this so? Perhaps because green tea not only captures the taste, aroma and color of spring, but delivers this delightful bouquet along with the highest concentration of beneficial phytonutrients and the least caffeine of all the teas.

Health Benefits

Green tea is particularly rich in health-promoting flavonoids (which account for 30% of the dry weight of a leaf), including catechins and their derivatives. The most abundant catechin in green tea is epigallocatechin-3-gallate (EGCG), which is thought to play a pivotal role in the green tea's anticancer and antioxidant effects. Catechins should be considered right alongside of the better-known antioxidants like vitamins E and C as potent free radical scavengers and health-supportive for this reason.

Most of the research showing the health benefits of green tea is based on the amount of green tea typically consumed in Asian countries-about 3 cups per day (which would provide 240-320 mg of polyphenols). Just one cup of green tea supplies 20-35 mg of EGCG, which has the highest antioxidant activity of all the green tea catechins.

The health benefits of green tea have been extensively researched and, as the scientific community's awareness of its potential benefits has increased, so have the number of new studies. As of November 2004, the PubMed database contained more than 1,000 studies on green tea, with more than 400 published in 2004! Following is a brief summary of some of the high points of this most current research.

Green tea drinkers appear to have lower risk for a wide range of diseases, from simple bacterial or viral infections to chronic degenerative conditions including cardiovascular disease, cancer, stroke, periodontal disease, and osteoporosis. The latest studies provide a deeper understanding of the ways in which green tea:

Protects against Death from All Causes, Especially Cardiovascular Disease

In August 2006, a European study, published in the European Journal of Clinical Nutrition, found that tea is a healthier choice than almost any beverage, including pure water, because tea not only rehydrates as well as water, but provides a rich supply of polyhenols protective against heart disease.

Now, a Japanese study published in the September 2006 issue of JAMA, suggests that drinking green tea lowers risk of death due to all causes, including cardiovascular disease.

Shinichi Kuriyama, M.D., Ph.D., of the Tohoku University School of Public Policy, Sendai, Japan, and colleagues examined the association between green tea consumption and death due to all causes, cardiovascular disease (CVD), and cancer.

The study, which began in 1994, followed 40,530 adults, ranging in age from 40 to 79, in northeastern Japan for up to 11 years. Within this region, 80% of the population drinks green tea with more than half consuming at least 3 cups a day.

Compared with participants who consumed less than 1 cup of green tea per day, those drinking 5 or more cups a day had a significantly lower risk of death from all causes and, specifically, risk of death from CVD, with women receiving even stronger protection than men:

Green Tea Benefits
In Women	In Men
23% lower risk of dying from any cause	12% lower risk of dying from any cause
31% lower risk of dying from CVD	22% lower risk of dying from CVD
62% lower risk of dying from stroke	42% lower risk of dying from stroke

Only weak or neutral relationships were seen between black tea or oolong tea and all-cause or CVD mortality.

While this study found no cancer-preventive benefit from drinking green tea, other large studies, including a meta-analysis of 13 studies published July 2006 in Carcinogenesis (Sun CL et al), suggest that green tea reduces risk of breast cancer. In this study, compared to women who did not drink green tea, those consuming the most green tea were 22% less likely to develop breast cancer.

Often in studies, the effects of a certain health-promoting behavior are likely to be confounded by the fact that those who try to follow a healthy lifestyle practice a variety of healthy habits. In this study, however, since green tea is the most commonly consumed beverage in Japan, it is unlikely that study participants were choosing to drink green tea primarily for their health, and thus also unlikely that the significant drop in risk of death due to all causes and CVD was due to other habits related to health consciousness.

Given the significant benefit green tea can provide, even to those who are not especially health conscious, just imagine its health-protective potential as part of your healthy way of eating!

If you simply cannot start your day without a cup of coffee, try enjoying a cup of green tea at your mid-morning break, with lunch or as an afternoon pick-me-up. You'll quickly discover green tea's irresistible combination of invigorating and calming qualities, plus its delicious flavor, make it one of your favorite healthy habits.

Protects against Coronary Artery Disease

In Japanese studies, green tea consumption has been found to be an independent predictor for risk of coronary artery disease. In one study, those drinking 5 or more cups of green tea each day were found to be 16% less likely to suffer from coronary artery disease. The relationship was so significant researchers concluded, "The more green tea patients consume the less likely they are to have coronary artery disease."

An elevation in the amount of free radicals in the arteries is a key event in many forms of cardiovascular disease. The latest research shows that green tea catechins inhibit the enzymes involved in the production of free radicals in the endothelial lining of the arteries. The arterial endothelium is a one-cell thick lining that serves as the interface between the bloodstream and the wall of the artery where plaques can form. By protecting the endothelium from free radical damage, green tea catechins help prevent the development of cardiovascular disease.

Inhibits Atherosclerosis

Green tea has been shown to effectively lower risk of atherosclerosis by lowering LDL cholesterol, triglycerides, lipid peroxides (free radicals that damage LDL cholesterol and other lipids or fats) and fibrinogen (a protein in the blood involved in the formation of blood clots), while improving the ratio of LDL (bad) to HDL (good) cholesterol.

In animal studies in which green tea was given in human equivalent doses to hamsters, atherosclerosis was inhibited 26-46% in those receiving the lower dose (equivalent in humans to 3-4 cups per day) , and 48-63% in those receiving the higher dose (10 cups a day in humans).

Special Benefits for Persons with High Triglycerides

Green tea may offer special heart-protective benefits for persons with high triglycerides, suggests a laboratory study, published in the February 2005 issue of the Journal of Nutrition.

A series of experiments revealed that the mix of catechins naturally found in green tea dose-dependently inhibit the activity of pancreatic lipase, the enzyme secreted by the pancreas that digests fat. As a result, the rate at which the body breaks down of fats into triglycerides, and the rise of triglyceride levels in the bloodstream that occurs after meals, is greatly slowed.

Since a large rise in blood levels of triglycerides after a meal is a significant risk factor for coronary heart disease, drinking a cup of two green tea along with your meals is a good idea, especially if your triglyceride levels are higher than normal.

Thins the Blood and Helps Prevent Blood Clots

Green tea catechins help thin the blood and prevent the formation of blood clots by preventing the formation of pro-inflammatory compounds derived from omega-6 fatty acids, which are found in meats and polyunsaturated vegetable oils such as corn, safflower and soy oil. These pro-inflammatory compounds-specifically, arachidonic acid from which the inflammatory cytokines thromboxane A2 and prostaglandin D2 are derived-cause platelets to clump together.

Protects the Heart in Patients with Acute Cardiovascular Disease

The primary catechin in green tea, EGCG (epigallocatechin-3-gallate) confers such powerful protection that it can help prevent the death of heart muscle cells following ischemia/reperfusion injury. Ischemia is the medical term for a restriction in blood supply and therefore in oxygen and nutrients. When circulation is restored, oxidative damage occurs, and this is referred to as reperfusion injury.

EGCG prevents heart muscle damage by blocking the activation of inflammation-related compounds (including NF-kappa-B and STAT-1) that play a critical role in promoting the oxidative damage that kills heart cells in reperfusion injury. Researchers believe EGCG can be used to help minimize damage in patients with acute coronary artery disease.

Minimizes Damage and Speeds Recovery after a Heart Attack

Research conducted over the last several years by Dr. Anastasis Stephanou and his team at the UK's Institute of Child Health and published in the FASEB Journal, the journal of the Federation of Experimental Biology and the Journal of Cellular and Molecular Medicine has focused on EGCG's ability to block the action of the protein, STAT-1. Normally activated in cells after a heart attack or stroke, STAT-1 plays a major role in inducing cell death.

Not only does green tea minimize heart cell death after a heart attack or stroke, ECGC also appears to speed up heart cells' recovery from damage, allowing the tissues to recover more quickly and alleviating damage to organs.

Dr. Stephanou, a molecular biologist, noted: "We're extremely encouraged by these findings and hope to implement them in the clinical setting to minimize cell death activation in patients with acute coronary heart disease."

Minimizes Damage to the Brain after a Stroke

EGCG has also been shown to protect brain cells by these same mechanisms and thus may help minimize the brain damage that occurs after a stroke. In one animal study, green tea was so effective in reducing the formation of free radicals in brain tissue that the researchers concluded, "Daily intake of green tea catechins efficiently protects the brain from irreversible damage due to cerebral ischemia, and consequent neurologic deficits."

Lowers Blood Pressure and Helps Prevent Hypertension

A study published in the July 2004 issue of the Archives of Internal Medicine found that among persons consuming tea regularly for at least one year, the risk of developing high blood pressure was 46% lower among those who drank ½ cup to 2 ½ cups per day, and 65% less among those consuming more than 2 ½ cups per day.

In another study, this one of rats bred not only have high blood pressure but also to be prone to strokes, those rats given green tea had significantly lower systolic and diastolic blood pressure compared to controls, who received plain water. The animals in this study, which was published in the January 2004 issue of the Journal of Nutrition, consumed the human equivalent of 1 liter (1.1 quarts or a little more than 4 cups) of green tea per day.

Helps Prevent the Development of Atherosclerosis and Cancer

In both atherosclerosis and cancer, cell growth and proliferation is central to the disease process. In atherosclerosis, plaques form in the lining of the arteries, which grow thicker and less elastic, impeding blood flow. In cancer, normal brakes on cells turn off, and they multiply out of control. Green tea can help stop abnormal cell proliferation.

Catechins, among the main active compounds in green tea leaves, shut down the primary relay station through which growth factors central to both atherosclerosis and cancer send their messages for growth. These relay stations, called tyrosine kinase receptors, are essential for the transmission of messages sent by platelet derived growth factor, insulin-like growth factor, epidermal growth factor, fibroblast growth factor, and vascular endothelial growth factor. The result is the prevention of or halting of the disease processes that depend upon excessive cellular growth.

Two other damaging factors that cause the cells lining our vasculature to proliferate are AGEs (advanced glycation end products) and MAPK (mitogen-activated protein kinase). AGEs form when sugars inappropriately bind to and distort proteins. MAPK activity is normally enhanced in the presence of elevated levels of LDL cholesterol. In laboratory studies, green tea polyphenols were shown to dose-dependently inhibit AGE-stimulated proliferation of vascular smooth muscle cells and to prevent the increase in MAPK normally seen when LDL levels are high.

Protects against Cancer

In the last ten years, green tea's cancer-preventive effects have been widely supported by epidemiological, cell culture, animal and clinical studies. For cancer prevention, the evidence is so overwhelming that the Chemoprevention Branch of the National Cancer Institute has initiated a plan for developing tea compounds as cancer-chemopreventive agents in human trials.

When confronted with a cancerous cell, green tea becomes the plant kingdom's Arnold Schwarzenegger, helping to terminate cancer cells in a remarkable number of ways.

Laboratory cell culture studies show that green tea polyphenols are powerful triggers of apoptosis (cell suicide) and cell cycle arrest in cancerous but not in normal cells. (Cell cycling is the process cells go through to divide and replicate.)

These anticancer actions have been assumed to be due to the powerful antioxidant effects of green tea's catechins, especially epigallocatechin-3-gallate (EGCG). This is a reasonable assumption, given that a number of studies have shown that green tea possesses remarkable antioxidant properties. In one study published in the November 2004 issue of Mutation Research, EGCG's protective antioxidant effects against several carcinogens were found to be 120% stronger than those of vitamin C.

But while green tea's antioxidant prowess is impressive, recent studies show it is far from the only way in which this multi-talented beverage protects us against cancer.

One of these mechanisms is green tea's ability to inhibit angiogenesis, the development of new blood vessels. Cancer cells, which are constantly attempting to divide and spread, have an endless appetite that can only be temporarily quieted by increasing the number of blood vessels that supply them with nutrients. By inhibiting angiogenesis, green tea helps starve cancer.

Studies also show that green tea works at the genetic level, shutting off genes in cancerous cells that are involved in cell growth, while turning on those that instruct the cancer cells to self-destruct. EGCG has even been found to work as a pro-oxidant or free radical, but just inside cancer cells, where it causes so much damage that the cancer cells' self-destruct mechanisms are triggered.

A study of ECGC's effects on keratinocytes (the major type of epidermal or skin cell) found that this green tea compound has yet another means of correcting cancer-that of turning on the genes that direct the cancer cell to return to normal.

Green tea's anticancer effects include its ability to inhibit the overproduction of the enzyme cyclooxygenase (COX)-2, a protein whose overproduction has been implicated as a factor in many diseases, including arthritis and cancer. COX-2 has an enzyme counterpart, called COX-1, which may be helpful to leave untouched when preventing overproduction of COX-2. Nonsteroidal anti-inflammatory drugs (NSAIDs) such as aspirin and ibuprofen (which inhibit both COX-1 as well as COX-2), and specific COX-2 inhibitors such as Vioxx and Celebrex (which inhibit only COX-2), have been considered as possible agents in the prevention of some forms of cancer, but their severe toxic side effects on normal cells limit their usefulness. In studies of prostate cancer cells, EGCG appears to block only COX-2 and to have no negative side effects.

Phytonutrients in green tea, specifically, its catechins, increase the production and activity of detoxification enzymes in humans, and may enhance our ability to detoxify carcinogens, shows research supported by the National Cancer Institute.

42 healthy volunteers refrained from tea or tea-related products for one month, after which blood samples were taken to assess the activity and levels of their glutathione S-transferases (GST), a major group of detoxification enzymes. Volunteers then consumed green tea catechins in amounts equivalent to consuming between 8-16 cups of green tea each day. GST activity was greatly enhanced in those whose baseline GST activity was low-those most susceptible to damage from carcinogens. (Chow HH, Hakim IA, et al.,Cancer Epidemiol Biomarkers Prev.)

Prostate Cancer

EGCG provides other benefits specific to prostate cancer prevention. A study published in the December 2004 issue of the International Journal of Cancer found that EGCG significantly inhibited, in a dose-dependent manner, the production of prostate-specific antigen (PSA), a marker for prostate cancer risk. Not only did EGCG lower PSA levels, but it also suppressed all the activities of PSA which were examined that promote prostate cancer.

Green tea polyphenols halt prostate cancer at multiple levels

The polyphenols in green tea help prevent the spread of prostate cancer by mobilizing several molecular pathways that shut down the proliferation and spread of tumor cells, while also inhibiting the growth of blood vessels that supply the cancer with nourishment, according to research published in the December 2004 issue of Cancer Research.

Green tea polyphenols:

• decrease insulin-like growth factor-1 (IGF-1), while increasing levels of IGF binding protein-3, which binds IGF-1, further diminishing its activity. (Increased levels of IGF-1 are associated not only with prostate cancer, but cancers of the breast, lung and colon.)
• inhibit key cell survival proteins, promoting apoptosis or programmed cell death in cancer cells.
• reduce the expression of several compounds (urokinase plasminogen activator and matrix metalloproteinase 2 and 9) involved in the metastasis and spread of cancer cells.
• reduce the amount of vascular endothelial growth factor (VEGF), which develops new blood vessels to carry nutrients to developing tumors.

All these effects were seen in this animal study within 6 months of continuous infusion. While obviously impractical for humans, the study suggests that daily consumption of green tea may be highly protective.

Choosing to regularly drink green tea and eat fruits and vegetables rich in the carotenoid, lycopene, may greatly reduce a man's risk of developing prostate cancer, suggests research published the Asia Pacific Journal of Clinical Nutrition (Jian L, Lee AH, et al.)

In this case-control study involving 130 prostate cancer patients and 274 hospital controls, men drinking the most green tea were found to have an 86% reduced risk of prostate cancer compared, to those drinking the least.

A similar inverse association was found between the men's consumption of lycopene-rich fruits and vegetables such as tomatoes, apricots, pink grapefruit, watermelon, papaya, and guava. Men who most frequently enjoyed these foods were 82% less likely to have prostate cancer compared to those consuming the least lycopene-rich foods.

Regular consumption of both green tea and foods rich in lycopene resulted in a synergistic protective effect, stronger than the protection afforded by either, the researchers also noted.

Practical Tips: Get in the habit of drinking green tea and eating lycopene-rich foods.

• Take a quart of iced green tea to work and sip throughout the day or take it to the gym to provide prostate protection while replenishing fluids after your workout.
• Pack a ziploc bag of apricots and almonds in your briefcase or gym bag for a handy snack.
• Start your breakfast with a half grapefruit or a glass of papaya or guava juice.
• Begin lunch or dinner with some spicy tomato juice on the rocks with a twis