WHFoods_ Green Tea

8/4/2019 WHFoods_ Green Tea

1/26

Foods: Green tea http://www.whfoods.com/genpage.php?pfriendly=1&tname=foodspic...

26 17.11.2007 23:06

All true teas-as distinct from herbal and flower infusions, which afficiandos calltisanes-are made from the leaves of a magnolia-related evergreen tree with thebotanical name ofCamellia sinensis. Although reaching a height of 30 feet in the wild, ontea plantations (called gardens or estates), the plant is kept as a shrub, constantlypruned 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 sealevel to 7,000 feet. The best teas, however, are produced by plants grown at higheraltitudes where the leaves mature more slowly and yield a richer flavor. Depending uponthe altitude, a new tea plant may take from 2 to 5 years to be ready for commercialpicking, 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 thesmallest and youngest leaves are picked for tea-the two leaves and bud at the top ofeach young shoot. The growth of new shoots, called a flush, can occur every week atlower altitudes but takes several weeks at higher ones. The new leaves are picked byhand by "tea pluckers," the best of whom can harvest 40 pounds per day, enough tomake 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 waythe leaves are processed, however, is even more important in developing the individualcharacteristics 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 beresponsible for most of the health benefits linked to green tea. Green tea is made bybriefly steaming the just harvested leaves, rendering them soft and pliable andpreventing them from fermenting or changing color. After steaming, the leaves arerolled, then spread out and "fired" (dried with hot air or pan-fried in a wok) until theyare crisp. The resulting greenish-yellow tea has a green, slightly astringent flavor closeto 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 tofermentation. Once again, they are spread out and kept under high humidity to promotefermentation, which turns the leaves a dark coppery color and develops black tea'sauthoritative flavor. Finally, the leaves are "fired," producing a brownish black tea whoseimmersion in hot water gives a reddish-brown brew with a stronger flavor than green oroolong 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 whoseflavor, 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 Chinawhere most historians and botanists believe the tea plant originated throughout all ofAsia. Why is this so? Perhaps because green tea not only captures the taste, aroma and


2/26


26 17.11.2007 23:06

color of spring, but delivers this delightful bouquet along with the highest concentrationof beneficial phytonutrients and the least caffeine of all the teas.

Health BenefitsDescriptionHistoryHow to Select and StoreHow to EnjoySafetyNutritional ProfileReferences

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 abundantcatechin in green tea is epigallocatechin-3-gallate (EGCG), which is thought to play apivotal role in the green tea's anticancer and antioxidant effects. Catechins should beconsidered right alongside of the better-known antioxidants like vitamins E and C aspotent 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 ofgreen tea typically consumed in Asian countries-about 3 cups per day (which wouldprovide 240-320 mg of polyphenols). Just one cup of green tea supplies 20-35 mg ofEGCG, 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 ofnew studies. As of November 2004, the PubMed database contained more than 1,000studies on green tea, with more than 400 published in 2004! Following is a briefsummary 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 simplebacterial or viral infections to chronic degenerative conditions including cardiovasculardisease, cancer, stroke, periodontal disease, and osteoporosis. The latest studies providea 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 ClinicalNutrition, found that tea is a healthier choice than almost any beverage, including purewater, because tea not only rehydrates as well as water, but provides a rich supply ofpolyhenols protective against heart disease.

Now, a Japanese study published in the September 2006 issue ofJAMA, suggests thatdrinking green tea lowers risk of death due to all causes, including cardiovasculardisease.

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, innortheastern Japan for up to 11 years. Within this region, 80% of the population drinksgreen tea with more than half consuming at least 3 cups a day.


3/26


26 17.11.2007 23:06

Compared with participants who consumed less than 1 cup of green tea per day, thosedrinking 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 thanmen:

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 andall-cause or CVD mortality.

While this study found no cancer-preventive benefit from drinking green tea, other largestudies, including a meta-analysis of 13 studies published July 2006 inCarcinogenesis(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 teawere 22% less likely to develop breast cancer.

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

Given the significant benefit green tea can provide, even to those who are not especiallyhealth conscious, just imagine its health-protective potential as part of your healthy wayof 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 calmingqualities, 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 independentpredictor for risk of coronary artery disease. In one study, those drinking 5 or more cupsof green tea each day were found to be 16% less likely to suffer from coronary arterydisease. The relationship was so significant researchers concluded, "The more green teapatients 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 formsof cardiovascular disease. The latest research shows that green tea catechins inhibit theenzymes involved in the production of free radicals in the endothelial lining of thearteries. The arterial endothelium is a one-cell thick lining that serves as the interfacebetween the bloodstream and the wall of the artery where plaques can form. Byprotecting the endothelium from free radical damage, green tea catechins help preventthe development of cardiovascular disease.

Inhibits Atherosclerosis

Green tea has been shown to effectively lower risk of atherosclerosis by lowering LDLcholesterol, 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 ofblood 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


4/26


26 17.11.2007 23:06

humans to 3-4 cups per day) , and 48-63% in those receiving the higher dose (10 cupsa 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 theJournal ofNutrition.

A series of experiments revealed that the mix of catechins naturally found in green teadose-dependently inhibit the activity of pancreatic lipase, the enzyme secreted by thepancreas that digests fat. As a result, the rate at which the body breaks down of fatsinto triglycerides, and the rise of triglyceride levels in the bloodstream that occurs aftermeals, is greatly slowed. Since a large rise in blood levels of triglycerides after a meal isa significant risk factor for coronary heart disease, drinking a cup of two green tea alongwith your meals is a good idea, especially if your triglyceride levels are higher thannormal.

Thins the Blood and Helps Prevent Blood Clots

Green tea catechins help thin the blood and prevent the formation of blood clots bypreventing the formation of pro-inflammatory compounds derived from omega-6 fattyacids, which are found in meats and polyunsaturated vegetable oils such as corn,safflower and soy oil. These pro-inflammatory compounds-specifically, arachidonic acidfrom which the inflammatory cytokines thromboxane A2 and prostaglandin D2 arederived-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 suchpowerful protection that it can help prevent the death of heart muscle cells followingischemia/reperfusion injury. Ischemia is the medical term for a restriction in blood

supply and therefore in oxygen and nutrients. When circulation is restored, oxidativedamage occurs, and this is referred to as reperfusion injury.

EGCG prevents heart muscle damage by blocking the activation of inflammation-relatedcompounds (including NF-kappa-B and STAT-1) that play a critical role in promoting theoxidative damage that kills heart cells in reperfusion injury. Researchers believe EGCGcan 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 histeam at the UK's Institute of Child Health and published in the FASEB Journal, thejournal of the Federation of Experimental Biology and theJournal of Cellular andMolecular 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 majorrole in inducing cell death.

Not only does green tea minimize heart cell death after a heart attack or stroke, ECGCalso appears to speed up heart cells' recovery from damage, allowing the tissues torecover more quickly and alleviating damage to organs. Dr. Stephanou, a molecularbiologist, noted: "We're extremely encouraged by these findings and hope to implementthem in the clinical setting to minimize cell death activation in patients with acutecoronary heart disease."

Minimizes Damage to the Brain after a Stroke

EGCG has also been shown to protect brain cells by these same mechanisms and thusmay help minimize the brain damage that occurs after a stroke. In one animal study,


5/26


26 17.11.2007 23:06

green tea was so effective in reducing the formation of free radicals in brain tissue thatthe researchers concluded, "Daily intake of green tea catechins efficiently protects thebrain from irreversible damage due to cerebral ischemia, and consequent neurologicdeficits."

Lowers Blood Pressure and Helps Prevent Hypertension

A study published in the July 2004 issue of theArchives of Internal Medicine found that

among persons consuming tea regularly for at least one year, the risk of developing highblood pressure was 46% lower among those who drank cup to 2 cups per day, and65% less among those consuming more than 2 cups per day.

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

Helps Prevent the Development of Atherosclerosis and Cancer

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

Catechins, among the main active compounds in green tea leaves, shut down theprimary relay station through which growth factors central to both atherosclerosis andcancer send their messages for growth. These relay stations, called tyrosine kinasereceptors, are essential for the transmission of messages sent by platelet derived growthfactor, insulin-like growth factor, epidermal growth factor, fibroblast growth factor, and

vascular endothelial growth factor. The result is the prevention of or halting of thedisease processes that depend upon excessive cellular growth.

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

Protects against Cancer

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

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

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

These anticancer actions have been assumed to be due to the powerful antioxidanteffects of green tea's catechins, especially epigallocatechin-3-gallate (EGCG). This is a


6/26


26 17.11.2007 23:06

reasonable assumption, given that a number of studies have shown that green teapossesses remarkable antioxidant properties. In one study published in the November2004 issue ofMutation Research, EGCG's protective antioxidant effects against severalcarcinogens 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 farfrom 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 developmentof 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 numberof blood vessels that supply them with nutrients. By inhibiting angiogenesis, green teahelps starve cancer.

Studies also show that green tea works at the genetic level, shutting off genes incancerous cells that are involved in cell growth, while turning on those that instruct thecancer cells to self-destruct. EGCG has even been found to work as a pro-oxidant or freeradical, but just inside cancer cells, where it causes so much damage that the cancercells' 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 ofturning 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 theenzyme cyclooxygenase (COX)-2, a protein whose overproduction has been implicatedas a factor in many diseases, including arthritis and cancer. COX-2 has an enzymecounterpart, called COX-1, which may be helpful to leave untouched when preventingoverproduction of COX-2. Nonsteroidal anti-inflammatory drugs (NSAIDs) such as aspirinand ibuprofen (which inhibit both COX-1 as well as COX-2), and specific COX-2 inhibitorssuch as Vioxx and Celebrex (which inhibit only COX-2), have been considered as possibleagents in the prevention of some forms of cancer, but their severe toxic side effects onnormal cells limit their usefulness. In studies of prostate cancer cells, EGCG appears toblock only COX-2 and to have no negative side effects.

Phytonutrients in green tea, specifically, its catechins, increase the production andactivity of detoxification enzymes in humans, and may enhance our ability to detoxifycarcinogens, shows research supported by the National Cancer Institute. 42 healthyvolunteers refrained from tea or tea-related products for one month, after which bloodsamples were taken to assess the activity and levels of their glutathione S-transferases(GST), a major group of detoxification enzymes. Volunteers then consumed green teacatechins 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-thosemost susceptible to damage from carcinogens. Cancer Epidemiol Biomarkers Prev.2007Aug;16(8):1662-6.

Prostate Cancer

EGCG provides other benefits specific to prostate cancer prevention. A study published inthe December 2004 issue of the International Journal of Cancerfound that EGCGsignificantly inhibited, in a dose-dependent manner, the production of prostate-specificantigen (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 mobilizingseveral molecular pathways that shut down the proliferation and spread of tumor cells,


7/26


26 17.11.2007 23:06

while also inhibiting the growth of blood vessels that supply the cancer withnourishment, according to research published in the December 2004 issue ofCancerResearch.

Green tea polyphenols:

decrease insulin-like growth factor-1 (IGF-1), while increasing levels of IGF binding protein-3, which bindsIGF-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 2and 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 carrynutrients 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 ofgreen tea may be highly protective.

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

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

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

Regular consumption of both green tea and foods rich in lycopene resulted in asynergistic protective effect, stronger than the protection afforded by either, theresearchers 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 prostateprotection 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 twist of lime. Snack on tomato crostini:in the oven, toast whole wheat bread till crusty, then top with tomato sauce, herbs, a little grated cheese, andreheat until the cheese melts.

Top whole wheat pasta with olive oil, pine nuts, feta cheese and a rich tomato sauce for lunch or dinner.

Drinking 5 cups of green tea a day may cut the risk of advanced prostate cancer in half,shows data collected in The Japan Public Health Center-based Prospective Study. TheJPHC Study followed 49,920 Japanese men aged from 40 to 69 from 1990 to 2004.Compared to men who drank less than one cup of green tea per day, those consuming 5or more cups daily reduced their risk of developing advanced prostate cancer by 48%! Ifyou don't already drink green tea, consider making this energizing, delicious beverage ahealthy habit. Over half a million new cases of prostate cancer are diagnosed each yearworld wide, and, incidence of the disease, which is the direct cause of more than200,000 deaths annually, is increasing with a rise of 1.7% over 15 years. Am J

Epidemiol. 2007 Sep 29.Ovarian Cancer

Green tea consumption has been shown to enhance survival in women with ovariancancer. In a study published in the November 2004 issue of the International Journal of


8/26


26 17.11.2007 23:06

Cancer, women with ovarian cancer who drank at least 1 cup of green tea daily had a56% lowered risk of death during the 3 years of the study compared to non-teadrinkers. A laboratory study of human ovarian cancer cells published in the September2004 issue ofGynecologic Oncologyexplains why: EGCG not only suppresses the growthof ovarian cancer cells, but also induces apoptosis (cell suicide) in these cells by affectinga number of genes and proteins.

An epidemiological (population) study published in the December 2005 issue of the

Archives of Internal Medicine, adds more evidence that enjoying a cup or two of teaeach day may significantly lower a woman's risk of ovarian cancer.

Data from numerous other studies has suggested that both green and black tea mayoffer protection against various cancers, with tea polyphenols thought to be the mostlikely protective agents. In this research, Susanna Larsson and Alicja Wolk from theNational Institute of Environmental Medicine, Stockholm, Sweden, decided to lookspecifically at the relationship between tea consumption and ovarian cancer.

Participants in their study were 61,057 Swedish women aged 40-76 years who were inthe Swedish mammography cohort and had completed a validated 67 item food

frequency questionnaire at baseline (between 1987-1990), after which the women werefollowed an average of 15.1 years.

Analysis of the data found that even women who averaged less than one cup of tea perday had an 18% lower risk of ovarian cancer than non-tea-drinkers.

Those who drank one cup per day had a 24% lower risk, and those who drank two ormore cups of tea per day had a 46% lower risk of ovarian cancer than non-tea-drinkers.

Each additional cup of tea per day was associated with an 18% lower risk of ovariancancer. Although higher tea consumption was generally associated with otherhealth-promoting behaviors, including higher consumption of fruits and vegetables, when

compared to the lifestyle behaviors of those who seldom or never drank tea, the largedrop in ovarian cancer risk seen as tea consumption increased does suggest that tea islikely to offer significant protection.

Breast Cancer

Recent studies have also identified two mechanisms through which green tea worksagainst breast cancer. Not only does EGCG inhibit the activity of telomerase, an enzymethat plays a key role in cell division, in breast cancer cells, but it also offers help towomen with estrogen-negative breast cancer, a form of breast cancer that is very hardto treat successfully.

Estrogen-negative breast cancer cells express high amounts of the epidermal growthfactor Her-2/neu, while in the more treatable estrogen-positive form of breast cancer,estrogen-receptor alpha (ERalpha) is expressed. According to a study published in theOctober 2004 issue ofMolecular and Cellular Biology, EGCG induces the expression ofERalpha rather than Her-2/neu in breast cancer cells.

Brain Tumors in Children

Green tea's ability to inhibit telomerase may also translate into help for children with themost common malignant brain tumors of childhood, primitive neuroectodermal tumors.Telomerase's activity allows cancer cells to avoid the normal limits on the number of

times a cell can replicate before it self-destructs. In a study published in the January2004 issue ofNeuro-oncology, investigators found that telomerase activity was at leastfive times higher in children with these brain tumors than in normal brain cells and thatEGCG strongly inhibited telomerase activity in a dose-dependent manner.


9/26


26 17.11.2007 23:06

Colorectal Cancer

Green tea may also reduce the increased risk for colon cancer caused by a high fat diet.An animal study published in the journal Nutrition and Cancerin 2003 found that whengreen tea was given along with a diet high in omega 6 fat (in the form of corn oil), theamount of pro-inflammatory compounds produced in the colon (5-lipoxygenase,leukotriene A4 hydrolase, and leukotriene B4) was significantly lower, as was theresulting number of precancerous colon cells (aberrant crypt foci). Green tea

consumption even reduced the amount of abdominal fat produced in the animals thatreceived it compared to controls.

Regular Green Tea Drinking Cuts Colorectal Cancer Risk in Half

To evaluate the link between green tea consumption and colorectal cancer risk,researchers followed 69,710 Chinese women ranging in age from 40 to 70 for 6 years.

Women who regularly drank green tea when the study began were 37% less likely todevelop colorectal cancer compared to infrequent green tea drinkers. Women whocontinued to drink green tea regularly throughout the study fared even better, reducingtheir risk of colorectal cancer by 57%.: Cancer Epidemiol Biomarkers Prev. 2007

Jun;16(6):1219-23..

Practical Tip: Enjoy green tea as both a hot and iced beverage.

Brew green tea with thinly sliced ginger and lemon, or sprigs of spearmint. Add one teaspoon of honey percup, stir and serve hot, or use half the amount of hot water (or twice the amount of tea), allow the tea to brewand cool, then combine half and half with fruit juice, such as peach, pineapple or papaya. Blend and pour overice.Make green tea chai by brewing green tea in hot vanilla soy milk. Top with a dash each of cinnamon, blackpepper, ginger and allspice.

Gallstones and Biliary Tract Cancers

Green tea lowers risk of gallstones and biliary tract cancers, suggests a largepopulation-based, case-control study led by Ann Hsing of the National Cancer Institute,Bethesda, Maryland, and published in the International Journal of Cancer, June 2006.

Hsing's team gathered demographic, medical and dietary data from 627 individuals withbiliary tract cancer, 1037 persons with gallstones, and 959 randomly selected controls inShanghai, China.

Among women, after taking account of age, education and body mass index, those whoconsumed at least one cup of tea each day for at least 6 months had a 27% reduced riskof developing gall stones, a 44% reduced risk of getting gallbladder cancer, and 35%reduced risk of bile duct cancer. Among men, most tea drinkers were cigarette smokers,

which likely affected their results. Men's risk of biliary disease was lower with teaconsumption, but the drop in risk was not considered statistically significant.

Lung Cancer

While we certainly do not recommend smoking, if you or someone you love smokes, or ifyou must be around smokers and are exposed to second hand smoke, drinking greentea can offer some protection against lung cancer. A human pilot study recentlyconfirmed the protective effects of green tea against lung cancer seen in cell culture andanimal studies. The study, published in the November 2004 issue ofMolecular Nutritionand Food Research evaluated the effect of green tea (5 cups per day) on 3 heavysmokers (>10 cigarettes a day) and 3 individuals who had never smoked. When thestudy subjects were drinking green tea, DNA damage caused by smoking wasdecreased, cell growth was inhibited, and cellular triggers for apoptosis (cell suicide) inabnormal cells increased.


10/26


f 26 17.11.2007 23:06

Another larger four month study of heavy smokers involving 100 women and 33 menfound that levels of urinary 8-hydroxydeoxyguanosine, a marker of free radical damageto DNA, dropped significantly in individuals drinking decaffeinated green but not blacktea.

Decaffeinated green tea was especially effective in reducing DNA damage in individualswho lack the genetic ability to produce normal amounts of an enzyme called glutathioneS-transferase, which plays a key role in the liver's ability to detoxify many of the

carcinogens found in cigarette smoke. Individuals whose genetic inheritance does notinclude the GSTM1 and GSTT1 variants of the genes that instruct the cell to produceglutathione S-transferase are more susceptible to developing many different cancers. Forthese individuals, green tea may be especially beneficial.

Bladder Cancer

Research by a multi-departmental team from UCLA has produced valuable insights intohow green tea extract might be capable of acting against the invasive growth of bladdercancer tumors. Green tea extract has been shown, via a mechanism that affects cellmovement, to target cancer cells while leaving healthy cells alone.

For cancer to grow and spread, the malignant cells must be able to move, and theirmovement depends on a process called actin remodeling, which itself is carefullyregulated by complex signaling pathways, including the Rho pathway.

By inducing Rho signaling, green tea causes cancer cells to mature more rapidly and tobind together more closely, a process called cell adhesion. Both their increased maturityand cell adhesion inhibit cancer cells' mobility, according to Rao, senior author of thestudy, published in the February 2005 issue ofClinical Cancer Research, in which greentea's effects on Rho signaling were noted.

"Cancer cells are invasive and green tea extract interrupts the invasive process of the

cancerIn effect, the green tea extract may keep the cancer cells confined and localized,where they are easier to treat and the prognosis is better," explained Rao.

About 56,000 new cases of bladder cancer are diagnosed each year, making it the fifthmost common cancer in the United States. About half of all bladder cancers are believedto be related to cigarette smoking. Bladder cancer can be difficult to detect in the early,most treatable stages, yet, when not found early, the tumors can be aggressive, andmore than half of patients with advanced cancers experience recurrences. In the nextphase of his research, Rao and his team will analyze urine from bladder patients, lookingparticularly for biomarkers associated with actin remodelling and the activation of theRho pathway, to determine which subset of patients might benefit most from green tea.

Improves the Efficacy of Cancer Drugs While Lessening Their Negative Side-Effects

In the fight against cancer, green tea polyphenols are team players, helpingcancer-killing drugs do their job. In a study published in the October 2004 issue of theournal of Pharmacy and Pharmacology, green tea polyphenols caused drug-resistant

cancer cells, which were able to extrude or push out one of the most commonly usedcancer drugs, doxorubicin, to retain the drug, which could then destroy them. Accordingto a study published in the August 2004 issue ofCancer Letters, another compound ingreen tea, the amino acid theanine, reduces the negative side effects of doxorubicin byincreasing the level of one of the body's most important internally producedantioxidants, glutathione, in normal tissues in the liver and heart-but not in tumors.

Understanding How Green Tea Fights Cancer

Spanish and British scientists have discovered at least one of the mechanisms throughwhich green tea helps to prevent certain types of cancer, according to a study published


11/26


f 26 17.11.2007 23:06

in the March 2005 issue ofCancer Research.

ECGC, a catechin present in green tea in amounts about 5 times higher than in blacktea, inhibits the enzyme dihydrofolate reductase (DHFR), which cancer cells need to beable to grow, and which is a well recognized target of anti-cancer drugs.

Scientists decided to look at ECGC after they realized the green tea catechin looks a lotlike the cancer drug methotrexate, which prevents cancer cells from making DNA by

inhibiting the DHFR enzyme. They discovered that ECGC kills cancer cells in the sameway as the drug.

Although ECGC binds strongly to DHFR, which is essential in both healthy and cancerouscells, it does not bind as tightly as methotrexate, so its side effects on healthy cells areless severe than those of the drug.

ECGC's binding to DHFR may also explain why women who drink large amounts of greentea around the time they conceive and early in their pregnancy may have an increasedrisk of having a child with spina bifida or other neural tube disorders.

Women are advised to take supplements of folic acid when trying to conceive and during

the first trimester (the first 3 months) of pregnancy because it is during this time periodthat the baby's neural tube is developing. Folic acid helps ensure normal developmentand protects against spina bifida by enabling the production of the enzyme DHFR. Whilea cup or two of green tea is unlikely to pose a problem, drinking large amounts of greentea could decrease the activity of DHFR, increasing risk of neural tube defects.

Improves Insulin Sensitivity in Type 2 Diabetes

Population studies suggest that green tea consumption may help prevent type 2diabetes. A number of animal studies are beginning to explain why. New studies suggestthat green tea may improve glucose tolerance and insulin sensitivity in individuals with

diabetes. In one study, after receiving green tea for 12 weeks, diabetic rats had lowerfasting blood levels of glucose, insulin, triglycerides and free fatty acids compared tocontrols, and the ability of their adiopcytes (fat cells) to respond to insulin and absorbblood sugar greatly increased.

In another study by the same research group, diabetic rats were separated into threegroups and followed for 12 weeks. One group was given with standard rat chow andwater (the control group), the second group received a high fructose diet and water(fructose group), and the third group got the same high fructose diet and green tea(green tea group). By the end of the study, the fructose group had high blood sugar,high insulin levels, and high blood pressure, while the animals receiving green tea along

with a high fructose diet showed improvement in all three.A study published in the August 2004 issue ofBMC Pharmacology, in which oral glucosetolerance tests were given to healthy humans after they consumed green tea, showedthat it increased the body's ability to utilize blood sugar.

Another interesting animal study compared the effects of a Western diet, a vegetariandiet and a Japanese diet, each with or without green tea. Blood sugar concentrationswere highest in the animals on the Western diet followed by the Vegetarian diet with theJapanese diet producing the lowest blood sugars. When supplemented with green tea,blood sugar levels dropped in rats on all three diets, with those on the Japanese diethaving not only the lowest blood sugars but also rating the best on other risk factors for

type 2 diabetes. Rats on the Japanese diet that also were given green tea had the lowesttriglycerides and cholesterol as well as the highest ratio of beneficial omega-3 fatty acidsto potentially inflammatory omega-6 fatty acids. The researchers concluded thatJapanese eating habits combined with drinking green tea might help prevent type 2


12/26


f 26 17.11.2007 23:06

diabetes.

One of the mechanisms through which green tea improves insulin sensitivity has recentlybeen identified in laboratory studies that show that epigallocatechin 3-gallate (EGCG)does a good deal more to prevent type 2 diabetes than lower the production of freeradicals. EGCG also works on the genetic level, causing a reduction in the number ofmessenger RNAs that direct liver cells to produce the enzymes involved in the creation ofglucose (sugar).

Protects against Kidney Disease

An animal study published in the January 2005 issue ofPharmacological Researchsuggests yet another beneficial effect of green tea consumption: the prevention ofkidney dysfunction in persons who must take powerful immunosuppressant drugs, forexample, after an organ transplant.

One such drug, cyclosporine A, while a very effective immunosuppressant, also markedlyelevates the production of free radicals highly toxic to the kidneys. In this study, ratsgiven green tea as their drinking water along with cyclosporine A produced far fewerdamaging free radicals than rats given plain water. In addition, a number of other

indicators of kidney function (serum creatinine, blood urea nitrogen, uric acid andurinary excretion of glucose) were significantly better in rats given green tea.

Another animal study published in May 2004 in theAnnals of Nutrition & Metabolismexplains why. Diabetic rats given green tea catechins and then exposed to akidney-damaging drug, streptozotocin, produced less than half the amount of superoxideradicals (a particularly damaging type of free radical) compared to diabetic rats on acatechin-free diet. As a result, a cellular waste product formed by free radical damage tofats, lipofuscin, was almost 200% higher in the diabetic rats who did not receive greentea catechins compared to those who did.

Builds Bone

Researchers at the University of Tokyo have shown drinking green tea may significantlyincrease bone mineral density.

Their study, presented at the International Osteoporosis Foundation World Congress onOsteoporosis, Toronto, Canada, June 5, 2006, included 655 women aged 60 years orolder. Participants completed a questionnaire about their consumption of green tea, milk,cheese, yogurt, fish, vegetable, tofu, natto (a soy food), meat and coffee; smoking,alcohol consumption, physical activity and use of anti-osteoporosis bisphosphonate drugslike Fosamax.

For each dietary item, subjects were divided into two groups: 1) those who consumedthe item five or more days per week, and 2) those who consumed the item fewer thanfive days per week. The researchers then measured the bone mineral density (BMD) ofthe women's lumbar spines, as well as blood markers for osteoporosis risk, includinglevels of calcium, phosphorus, parathyroid hormone, alkaline phosphatase, osteocalcin,and vitamin D.

Women who drank green tea 5 or more days per week had an average BMD significantlyhigher (0.808 grams of hydroxyapatite-form calcium per square centimeter) than thosedrinking green tea less than 5 days per week (0.738 grams per square centimeter).

Green tea drinkers' bone-density advantage persisted even after results were adjustedfor age, body mass index, other dietary items, smoking, alcohol, physical activity anduse of osteoporosis drugs.

The Tokyo team hypothesized the catechin flavonoids in green tea provided the benefits


13/26


f 26 17.11.2007 23:06

via estrogenic effects known to build bone strength and/or induce apoptosis ("suicide")in bone-destroying cells called osteoclasts. Both mechanisms are similar to the ways inwhich bisphosphonate drugs like Fosamax prevent bone loss. But while these potentdrugs can provoke inflammatory eye disorders, abdominal pain, nausea, vomiting,dyspepsia and diarrhea, green tea is not only completely safe, but a delicious beveragethat offers a legion of other health benefits.

Green Tea Provides Bone Benefits Similar to Calcium or Exercise

Australian researchers report that bone mineral density (BMD) is 2.8% greater in teadrinkers than non-drinkers. The study involved 1,500 women (age range from 70-85) ina 5-year prospective trial looking at the effects of calcium supplements on osteoporoticfracture. Not only was tea drinkers' total BMD 2.8% higher than non-tea drinkers, butover the course of 4 years, tea drinkers lost an average of 1.6% of their total hip BMD,while non-tea drinkers lost more than twice as much (4%).

The 4 primary polyphenols in tea (epigallocatechin gallate (EGCG), epigallocatechin,epicatechin gallate, and epicatechin) were identified as being responsible. Green teacontains between 30-40% of water-extractable polyphenols, while black tea containsbetween 3-10%. "A recent review suggests that flavonoids from green tea may beassociated with increases in BMD via a potent stimulatory effect on osteoblast function,"noted lead researcher Amanda Devine. (Osteoblasts are the cells responsible forproducing new bone.) Am J Clin Nutr. 2007 Oct;86(4):1243-7.

Prevents Osteoporosis and Periodontal diseases

Excessive bone loss is a characteristic feature not only of osteoporosis but of periodontaldisease. Green tea supports healthy bones and teeth both by protecting osteoblasts (thecells responsible for building bone) from destruction by free radicals, and by inhibitingthe formation of osteoclasts (the cells that break down bone).

Another benefit of green tea consumption for those with periodontal disease: green teashort circuits the damaging effects of the bacteria most responsible for gum disease,Porphyromonas gingivalis. P. gingivalis causes gum damage by producing toxicbyproducts such as phenylacetic acid and by stimulating the activity and production ofenzymes called metalloproteinases (MMPs), which destroy both the mineral and organicconstituents that make up the matrix of our bones. Epigallocatechin-3-gallate (EGCG)inhibits P. gingivalis' production of both phenylacetic acid and MMPs.

Protects the Liver from Alcohol and Other Harmful Chemicals

Alcohol metabolism results in the production of damaging free radicals that canoverwhelm the liver's supply of antioxidants, resulting in liver injury. In a study

published in the January 2004 issue ofAlcoholin which rats were chronically intoxicatedwith alcohol for 4 weeks, green tea prevented damage to their livers.

Other animal research shows that epigallocatechin-3-gallate (EGCG) protects the liveragainst the free radicals generated when mice are exposed to carbon tetrachloride, atoxic chemical solvent. Without the protection afforded by EGCG, carbon tetrachlorideexposure resulted in the production of numerous free radicals that destroyed asignificant amount of the animals' liver cells. With EGCG, free radical production and liverinjury was so greatly reduced that researchers suggested green tea should be used inthe treatment of liver disease.

Unlike some herbs, green tea's protective effects do not appear to affect two of the liverenzymes most often responsible for detoxifying and eliminating drugs, cytochrome P-4502D6 and 3A4. This suggests that green tea might be safely consumed when takingmedications primarily dependent upon the CYP2D6 or CYP3A4 pathways of metabolism.Hopefully, future research studies will bear out this potential benefit.


14/26


f 26 17.11.2007 23:06

On the other hand, one study found that Japanese green tea did increase the activity ofthe CYP1A1 enzyme. Researchers hypothesized that the increase in activity of this liverenzyme may be one of the ways in which green tea helps protect against cancers causedby various dietary carcinogens.

Promotes Fat Loss

Green tea not only promotes fat loss, but specifically, the loss of visceral fat-fat that

accumulates in the tissues lining the abdominal cavity and surrounding the intestines(viscera) and internal organs. Unlike fat deposits on the hips and thighs (which result inthe so-called "pear" body shape), visceral fat (which produces the "apple" body shape) ishighly associated with increased risk for metabolic syndrome and type 2 diabetes.

Green tea contains three major components that promote fat loss: catechins, caffeineand theanine. Studies suggest that green tea compounds promote fat loss by inhibitingboth gastric and pancreatic lipase, the enzymes that digest triglycerides, and fatty acidsynthetase, the enzyme responsible for synthesizing fatty acids into the form in whichthey can be stored in the body's adipose (fat) cells.

In a study published in the January 2004 issue ofIn Vivo in which mice were fed diets

containing 2% green tea powder for 16 weeks, visceral fat decreased by 76.8% in thosereceiving green tea compared to the control group. Green tea also decreased bloodlevels of triglycerides (the chemical form in which most fats exist in the body).

A human study, published in the January 2005 issue of theAmerican Journal of ClinicalNutrition, confirms green tea's ability to not only reduce body fat, but damage to LDLcholesterol as well. After 12 weeks of drinking just one bottle of green tea each day, 38normal-to-overweight men in Tokyo had a significantly lower body weight, BMI, waistcircumference, body fat mass and amount of subcutaneous fat compared to men given abottle of oolong tea each day. After a 2 week diet run-in period, the men were dividedinto two groups, one of which drank a bottle of green tea containing 690 mg of

catechins, while the other group drank a bottle of oolong tea containing 22 mgcatechins. Not only did the men drinking green tea lose weight and fat, but the amountof their LDL cholesterol damaged by free radicals also dropped significantly. Sinceatherosclerotic plaques develop when cholesterol circulating in the bloodstream isdamaged or oxidized, green tea's ability to prevent these oxidation reactions mayexplain some of its protective effects against cardiovascular diseases.

Increases Exercise Endurance

Green tea extract given to lab rats over a 10-week span increased the amount of timethe animals could swim before becoming exhausted by as much as 24%.

Green tea's catechins appear to stimulate the use of fatty acids by liver and muscle cells.In muscle cells, the ability to burn more fat translates into a reduction in the rate atwhich glycogen, the form in which carbohydrates are stored for ready access in muscle,is used up, thus allowing for longer exercise times. Green tea's effect on muscle cells'ability to take in and burn fatty acids, speeding up fat breakdown, is also thought to bethe reason why it helps weight loss.

The idea for the experiment came from the fact that skeletal muscles utilizecarbohydrates, lipids (fats) and amino acids (protein) as energy sources, but the ratio inwhich they are used varies with the intensity and type of the exercise, and the level ofthe individual's fitness. During endurance exercise, the use of too much carbohydrate is

undesirable because it triggers insulin secretion, which, in turn, both inhibits the burningof fatty acids and stimulates lactic acid production. (Lactic acid buildup is what causesthat sore achy feeling in your muscles when you exercise.) Conversely, enhancedavailability and utilization of free fatty acids reduces carbohydrate utilization, which inturn spares glycogen (the form in which carbohydrates are stored in muscle for quick


15/26


f 26 17.11.2007 23:06

use) and suppresses lactic acid production, resulting in an increase in endurance."

Drinking a single cup of green tea before exercise, however, will not be effective. Onesingle, higher "dose" of green tea did nothing to improve lab rats' performance. Theanimals had to receive green tea daily, and endurance increased gradually over the 10weeks of the study. To match the beneficial effect on test animals' endurance capacityseen in the experiments, the researchers estimate a 165-pound athlete would need todrink about 4 cups of green tea daily.

Protects against Cognitive Decline, Alzheimer's Disease and Parkinson's Disease

Damage to brain cells in Parkinson's, Alzheimer's and other neurodegenerative diseasesseems to result from the combination of a number of damaging factors includingexcessive inflammation and increased levels of iron, both of which lead to increased freeradical production, exhaust the brain's supply of protective antioxidants and trigger theproduction of certain proteins, such as amyloid-beta, which promote apoptosis (cellsuicide).

Green tea catechins, until recently thought to work simply as antioxidants, are nowknown to invoke a wide spectrum of neuroprotective cellular mechanisms. These include

iron chelation, scavenging of free radicals, activation of survival genes and cell signalingpathways, and regulation of mitochondrial function. (The mitochondria are the energyproduction factories inside our cells. When they are not working properly, they generatemany free radicals and little energy.) The end result is a significant lessening of damageto brain cells.

Iron accumulation in specific brain areas and free radical damage to brain cells areconsidered the major damaging factors responsible for a wide range ofneurodegenerative disorders including both Parkinson's and Alzheimer's disease.

In the brain, epigallocatechin-3-gallate (EGCG) has been shown to act as an iron

chelator, binding to and removing iron, thus preventing it from contributing to theproduction of free radicals. In addition to removing iron, EGCG also increases the activityof two major antioxidant enzymes, superoxide dismutase (SOD) and catalase, furtherhelping to decrease free radical damage.

Another active compound in green tea, epicatechin (EC), reduces the formation of aprotein called amyloid-beta. Plaque-like deposits of amyloid-beta in the brain are adefining characteristic of Alzheimer's disease.

Animal studies conducted at the Douglas Hospital Research Centre, McGill University,Quebec, Canada, suggest that a daily cup or two of either black or green tea may reduce

the risk of age-related degenerative brain disorders such as Alzheimer disease.The researchers looked at the protective effects of two tea extracts and their mainconstituents, epigallocatechin gallate and epicatechin gallate, which are highlyconcentrated in green tea, on dying nerve cells. Both black and green tea extracts andcatechins strongly blocked death of neurons (brain nerve cells) When researchersexposed cultured neurons to amyloid alone, its effects were so toxic that the brain cellsdied, but when the cell cultures received amyloid immediately followed by tea extractsand catechins, the neurons were rescued and survived.

Green tea polyphenols have also demonstrated the ability to affect cell signalingpathways, in particular the MAPK pathways, which are triggered by oxidative stress (free

radicals), and themselves set in motion a series of chemical reactions so damaging thatthey can result in brain cell death. MAPK signaling pathways inside brain cells arethought to play a critical role in neurodegenerative diseases.

Another important cell signaling pathway beneficially affected by EGCG, the PKC


16/26


f 26 17.11.2007 23:06

pathway, is also thought to play an essential role in the regulation of cell survival andprogrammed cell death.

Although no human studies on Alzheimer's disease have yet reported benefit from teaconsumption, recent population studies have shown that simply consuming 2 or morecups of green tea daily reduces risk of cognitive decline and Parkinson's disease.

Green Tea Keeps Elders Mentally Sharp: Research Showing Multiple Ways

Green tea helps slow the age-related decline in brain function seen as declining memory,cognitive impairment, dementia and Alzheimer's, shows a human study published in theFebruary 2006 issue of theAmerican Journal of Clinical Nutrition.

Researchers at Japan's Tohoku University studied 1003 subjects over age 70, comparingtheir green tea intake and mental sharpness, using a Mini-Mental State Examination, awell-accepted standardized test for measuring cognitive function.

Drinking more than 2 cups a day of green tea slashed odds of cognitive impairment inelderly Japanese men and women by 64%! And a Japanese cup of green tea is muchsmaller than its American counterpart-only about 3.2 fluid ounces.

And at every level of cognitive impairment-from minimal to severe-those drinking themost green tea experienced significantly less mental decline than those drinking theleast:

Compared with elderly Japanese who drank less than 3 cups a week, those drinkingmore than 2 cups a day had a 54% lower risk of age-related declines in memory,orientation, ability to follow commands and attention.

Those drinking 4 to 6 cups of green tea a week (1 cup a day) had a 38 lower risk ofdeclines in brain function.

Green tea's primary protective agent is thought to be its catechin phytonutrientepigallocatechingallate or EGCG. Research shows this highly potent antioxidant:

helps prevent the formation of B-amyloid, a protein whose accumulation is recognized as causing Alzheimer's(Basianetto S, Eur J NeurosciJan 2006).protects brain cells by chelating (removing) iron, which might otherwise produce destructive free radicals(Reznichenko L,J Neurochem, March 2006).helps prevent oxidative stress-induced brain cell death by "talking" to brain cells' genes responsible for cellcycling and survival. Specifically, EGCG tells the genes in neurons to decrease production of caspase 3, anenzyme involved in initiating programmed cell death. (Park HJ, Life SciJan 2006; Levites Y.J Biol Chem,2002)promotes memory-related learning ability by protecting cells in the hippocampus, a part of the brain involvedin spatial cognition and memory-related learning ability, from free radical damage (Haque AM,J NutrApril

2006).

Green Tea Fights the Flu

A cup of green tea may help prevent or lessen the duration of the flu. In a lab study,published in the November 2005 issue ofAntiviral Research, EGCG dramatically inhibitedinfluenza virus replication in cell culture in all the subtypes of influenza virus tested.EGCG appears to suppress viral RNA synthesis by altering the properties of the viralmembrane.

Pepper increases EGCG availability

An animal study suggests that consuming the spice, black pepper, when drinking green

tea can significantly increase the amount of epigallocatechin-3-gallate (EGCG) absorbed.In this study, rats and mice given green tea along with piperine (a bioactive componentin black pepper) absorbed 130% more EGCG than control animals receiving EGCG alone.

In this study, piperine was found to inhibit the glucuronidation of EGCG in the intestines.


17/26


f 26 17.11.2007 23:06

Glucuronidation is a chemical pathway that serves as one of the major ways our bodiesconvert drugs, steroids, and many other substances into metabolites that can then beexcreted into the urine or bile. By inhibiting EGCG's glucuronidation, piperine allowedmore of this catechin to be absorbed and utilized. So, next time you have a cup of greentea along with a meal, be sure to spice up your soup, salad and/or entre with a littlefreshly ground black pepper.

Description

An oriental evergreen tree that can reach a height of 30 feet in the wild, the tea plant iskept as a shrub on tea plantations, where it is pruned to a height of about 3 feet toencourage new growth. A relative of the camellia with the botanical name ofCamelliasinesis, the tea plant produces abundant foliage, a camellialike flower and berriescontaining one to two seeds. Only the smallest, youngest parts of the plant&mdah;thetwo leaves and bud at the tip of each new shoot-are picked for tea.

History

The tea plant, source of the most popular beverage in the world, is believed to haveoriginated in the landmass encompassing Tibet, western China, and northern India.

According to ancient Chinese legend, tea was discovered by the Chinese emperorShen-Nung in 2737 B.C., when leaves from a wild tea bush accidentally fell into a pot ofwater he was boiling. The first recorded mention of tea appears in a contract for slavesknown as "Tan Yuch," written by Wang Pao, poet laureate to Emperor Husan, in 59 B.C.By 780 A.D., when Lu Yu's The Classic of Tea was published in China, the cultivation andconsumption of tea, whose name derives from the Chinese Amoy dialect word "t'e,"pronounced "tay," had developed into a fine art. Today, "cha" means tea in Chinese. Asthis word moved westward into Middle Eastern languages, it sometimes became alteredto "chai."

India attributes the discovery of tea to the Buddhist monk Siddhartha in the 6th century.

Legend has it that the prince-turned-monk traveled north from India to China to preachBuddhism, vowing he would meditate without sleeping for nine years. Reaching Cantonin 519 A.D., he stationed himself before a wall of meditation where, after a mere fiveyears, he was overcome by drowsiness. Inspired by divine intervention, he picked andchewed the leaves of a nearby tree, discovering, to his delight, a great sense ofalertness and well-being. The tree whose health-giving properties enabled him to keephis vow was, of course, Camellia sinesis, whose leaves and seeds he carried with him ashe continued his journey into Japan. In Japan, Buddhist monks quickly embraced tea,using it to remain alert during their own meditations and creating a simple drinking ritualthat several hundred years later, tea master Sen-no Rikyu (1521-1591) developed intothe high art ofchanoyu, the Japanese tea ceremony.

From Japan, where tea was widely cultivated and consumed by the 9th century A.D., teaculture spread to Java, the Dutch East Indies, and other tropical and subtropical areas.In the 16th century, traders from Europe sailing to and from the Far East introducedEuropeans to the delicious Asian drink, and by the 18th century, tea had become thenational beverage of England.

Thousands of Chinese bushes stealthily acquired by botanist Robert Fortune, a "spy" forGreat Britain's East India Trading Company, were introduced into India in the 1840s,where they quickly became a popular and profitable crop for the Empire.

Tea crossed the Atlantic with the American colonists, among whom its popularity led tothe British imposition in 1767 of a tea tax that so infuriated the colonists that theyrevolted, tossing tons of tea into the harbor in 1733 in what became known as theBoston Tea Party. Freedom from unfair British taxation, symbolized by the tax on tea,became a central contributing factor to the Revolutionary War. The type of tea tossed


18/26


f 26 17.11.2007 23:06

into Boston harbor? Probably green since it was likely "gunpowder tea," green tea rolledtightly into pellets that looked like gunpowder shot to preserve its freshness during longvoyages.

Several new innovations in tea consumption originated in the United States. In 1904,when a New York City merchant, Thomas Sullivan, sent his customers samples of tea insmall silk bags, they found the bags could be used to conveniently brew a single cup oftea, and the tea bag was born. Another American innovation in tea drinking, instant tea,

was first marketed in 1948.

Today, not China but India ranks as the number one producer of tea, although Sri Lanka(formerly Ceylon) is the major tea supplier to the U.S. Worldwide, more than 2.5 millionmetric tons of tea are produced each year with India, China, Sri Lanka, Kenya,Indonesia, Turkey, U.S.S.R, Japan, Iran and Bangladesh being the leading tea growingcountries.

How to Select and Store

Whenever possible, ask for a sample of prepared tea before buying. Most high-qualityteas will produce a pale green to yellow-green cup.

Loose Tea

To test for freshness, tightly squeeze a small amount and smell the aroma. The freshest,most flavorful tea will smell sweet and grassy.

Tea Bags

To test tea bags for freshness, remove the tea from one bag, place the empty bag in acup, pour hot water over it., and let it steep for 2-3 minutes. If the result takes like plainhot water, the tea itself is likely fresh. If the tea bag water tastes like tea, the tea is old,and the paper has absorbed its flavor.

Since a single ounce of tea should produce 15 to 30 cups, the best way to ensure yourtea is fresh is to purchase it in small amounts-two to four ounces at most. To retainfreshness and flavor in both loose and bagged tea, store it in a tightly constructedopaque container to protect it from light, moisture and food odors.

Dark glass or ceramic containers are best; tins often leak as their seams are soldered.Use a small container just large enough to accommodate the amount of tea; teaexposed to the air in a half-empty large container will continue to oxidize.

It's best to store tea in a dark, cool, dry cupboard. Tea stored in the refrigerator isvulnerable to moisture and odors from other foods, and the water condensation thatoccurs when frozen tea is defrosted can ruin it.

The following are just a few delicious green teas available in most serious tea shops,mail-order catalogues and on-line sources of fine green teas:

Chinese Green Teas

The best Chinese green teas are thought to be those picked in early spring at the time ofthe Qing Ming festival, which takes place on April 5th of the solar calendar. Theseinclude:After the Snow Sprouting: among the first tender sprouts available after thewinter snows, these leaves produce a delicate tea with a fresh green scent. Ching Ca:

grown in mainland China, these teas include the famous Pi Lo Chun and Tai Ping HouGui. Chun Mei(Precious Eyebrows): a name reflecting the fact that these springtimeleaves are twisted into small curved shapes like lovely eyebrows. This high-grown teafrom Yunnan province should be brewed lightly to produce an amber liquid with awonderful aftertaste reminiscent of plums. Dragonwell: with a fresh green taste, this is


19/26


f 26 17.11.2007 23:06

the favorite green tea of mainland China. The highest grade of this tea, Qing Ming, isnamed for the opening spring festival when the finest teas are picked.Green Pearls:each pearl unfurls into three or four leaves that yield a lovely golden aromatic brew.Gunpowder: a combination of buds and young green leaves rolled into balls reminiscentof gunpowder shot (hence its name), these also unfurl when infused. To test thefreshness of gunpowder tea, pinch or squeeze a pellet. If fresh, it will resist; if stale, itwill crumble. Two excellent gunpowder teas with a sweet, grassy taste are GunpowderPinhead Temple of Heaven and Gunpowder Temple of Heaven. Guzhang Maohan (Mao

Jin): these tea leaves from the Yellow Mountains of Anhui province produce a darkerbrew with a sweet, smoky flavor. Pan Long Yin Hao: from Zhejiang province, this tea, arepeat winner in tea competitions conducted by the Chinese Ministry of Agriculture, isdescribed as "a complex brew of multiple flavor notes." Po Lo Chun: which translates to"Astounding Fragrance," aptly describes this slightly sweet yellowish tea with a lovelyaftertaste. Snow Dragon: grown near the border between Fujian and Zhejiang province,this tea is roasted in a large wok to produce a nutty, sweet flavor.Yunnan GreenNeedle: a pleasantly astringent clean-tasting tea made from delicate green buds.

Organic Green Teas

The most stringent standards for organic produce are found in California, Japan andGermany. Any tea that meets these standards is a high quality organic product.

The two most respected organic tea farms are in India: the Oothu Tea Estate, the firstorganic tea farm in the world, and Makaibari Tea Estates, which follows RudolphSteiner's principles of harmony with nature through organic, sustainable methods ofagriculture.

Indian Green Teas

Although green teas are a very small part of overall tea production in India, the followingare notable. Bherjan Estate: an organic green tea grown in Assam, India's most plentiful

tea district. Assam teas are renowned for their hearty taste and "strength" in aroma andbody.Ambootia Tea Estate: a Darjeeling district organic green tea that produces a light,fragrant cup. Makaibari Tea Estates: a multiple award winning Darjeeling green tea,flavorful but light. Craigmore Estate: grown at high altitutes in the spectacular range ofthe Nilgiris, India's Blue Mountains, these green teas are exceptionally fragrant andsweet.

Japanese Green Teas

The best quality green teas are grown in the prefectures of Shizuoka and Uji.Ban-cha:an earthy brown tea with an astringent taste made from roasted green tea leaves,bancha should only steep two to three minutes or it will become bitter. Houjica: a lightly

roasted bancha tea with a nutty flavor. A good nighttime choice as it is very light andlow in caffeine. Sen-cha: about 75% of the green tea harvested in Japan is Sencha,making it the most commonly consumed green tea in Japan. Sencha is especially rich invitamin C and provides a clear rich yellow-green liquor that is grassy sweet and cleanlyastringent. Made from a higher quality leaf than bancha or houjica, sencha is often called"guest tea." The most delightful sencha is Sencha Sakuro, a spring green tea scentedwith cherry blossoms. Another cherry-scented sencha to try is Spiderleg Sakuro whoselonger, more "spidery" leaves produce a rich flavorful bouquet.Gyokuro: the highestquality Japanese green tea, gyokuro has been called "history, philosophy and art in asingle cup." For three weeks before the spring harvest, gyokuro leaves are shaded fromdirect sunlight, leading to a slower maturation that enhances the leaves' content of

flavenols, amino acids, sugars and other substances that provide green tea's healthbenefits, aroma and taste. Intensely green and sweeter than sencha, gyokuro leaves canserve as the base for matcha-the silky chartreuse tea powder used to make chanoyu,the tea of the Japanese tea ceremony. Mat-cha: Matcha differs from gyokuro in that the


20/26


f 26 17.11.2007 23:06

leaves are not rolled. After steaming, they are immediately and thoroughly dried, afterwhich they are called tencha. Tencha is then ground into the superfine powder known asmatcha. Use about two level teaspoons of matcha to cup water and whip into a thick,invigorating brew, wonderful as an energizing morning tea or before exercise.Shin-cha:In Japanese, "shin" means new and "cha" means tea. Shincha is literally "new tea" as itconsists of leaves very lightly steamed immediately after harvesting. Shincha, which isonly sold from May through July, is a highly aromatic tea with the aroma of freshlypicked leaves. Because it is quite perishable, only a very small percentage of the tea

harvest is processed as shincha; most of the leaves are used for sencha. Genmai cha:Made from sencha mixed with genmai (puffed brown rice), this tea may be made fromlower quality second harvest sencha but can also be found made from premium first-leafsencha. The rice supplies a slightly nutty taste. Some tea retailers also add a pinch ofmatcha to the blend, giving it a vibrant green color.

How to Enjoy

Tips for Preparing

Green tea should be handled tenderly, just as you would fresh green leafy vegetables.

Spring water is the ideal choice for brewing tea, followed by filtered water. Distilledwater should never be used; the brew it produces will be flat since the minerals removedfrom it are essential to bringing out tea's flavor.

To prepare the best loose tea, we recommend using a small food scale. Use three gramsof tea to five ounces of water if brewing tea in a small teapot; four grams of tea to eightounces of water for other methods.

As the size and shape of tea pots and cups varies considerably, it's a good idea to fill ameasuring cup with 8 ounces of water and pour it into your tea pot or cup to determinehow much water it really holds.

In making loose tea, remember that a teaspoon of small, dense leaves will weighsubstantially more than a teaspoon of larger leaves, and the resulting tea will reflectthis. A teaspoon of small dense leaves may be sufficient to produce a satisfying strongcup, while several teaspoons of larger leaves would be needed for a comparable brew.

Although heartily boiling water is used to brew black and oolong teas, green tea needsmuch lower temperatures (160-170 degrees F; 79-85 degrees C) and should be brewedfor less time.

Let the water barely reach the boiling point to liberate its oxygen, then allow it to coolslightly before pouring over your tea. Until you are familiar with your tea kettle and the

time it takes and sounds it makes when the correct temperature (170-185 degrees) hasbeen reached, it's a good idea to check using a simple, inexpensive candy thermometer,available at any grocery store.

Brewing for 30 seconds to one minute is usually ideal; however, Nilgiri and Darjeelinggreens can take several minutes, and Chinese Dragonwell teas are often best after 6-7minutes of infusion.

Although good quality tea leaves will sink to the bottom after they have infused, it's agood idea to pour the tea over a small strainer if one is not built in to your teapot.

Quick Serving Ideas

Brew green tea with thinly sliced ginger and lemon, or sprigs of spearmint. Add oneteaspoon of honey per cup, stir and serve hot or use half the amount of hot water (ortwice the amount of tea), allow the tea to brew and cool, then pour over ice cubes.


21/26


f 26 17.11.2007 23:06

Make a green tea chai by brewing green tea in hot vanilla soy milk and topping with adash each of cinnamon, black pepper, ginger and allspice.

Brew 1-2 teaspoons loose leaf green tea in 8 ounces cool water for 20-30 minutes todevelop flavor without bitterness and add to stir-fries, marinades, dressings, soups andsauces.

Sprinkle gyokuro tea over a salad, stew or rice dish.

Add teaspoon gyokuro tea to an almost set omelet or scrambled eggs.

Add crushed gunpowder tea and rice vinegar to sesame oil for a delicious vinaigrette.

Mix gyokuro tea with sesame seeds and sea salt and use to dredge shrimp or fish filetsbefore lightly pan-frying them.

Cook Japanese udon noodles in green tea for about 5 minutes, then remove from heatand leave noodles in tea until cool. Drain and toss lightly with soy sauce and sesame oil.Add thinly sliced tofu, scallions, mushrooms, and chopped cilantro, and serve.

Poach Asian or Bosc pears in green tea with fresh thinly sliced gingerroot. Drizzle withhoney and top with a sprig of fresh mint.

Combine cooled green tea half and half with a fruit juice, such as peach, pineapple orpapaya. Sweeten with a teaspoon of honey per cup. Blend and pour over ice.

Safety

Green Tea and Caffeine

Green tea contains caffeine, although half that found in coffee. The amount of caffeinethat ends up in your cup of green tea will vary according to the amount of tea used, the

length of time the leaves are infused, and if you drink the first or second infusion. Mostof the caffeine in green tea is extracted into the water the first time the tea isinfused.The table below compares the average amount of caffeine found in tea, othercaffeinated drinks and chocolate.

There is limited research in the published literature comparing the caffeine content ofgreen vs black tea. A recent study1 measured the caffeine content in the dry matter ofthe tea leaves, an approach that allows for control of any confounding variables relatedto preparation techniques that may impact the caffeine content in the final tea product.This study found that the caffeine content of one gram of black tea ranged from 22-28milligrams while the caffeine content of one gram of green tea ranged from 11-20

milligrams, reflecting a significant difference. (Please note that not all of the caffeinefrom the tea leaves is extracted into the tea beverage, so these numbers only provide arelative level of caffeine difference between black and green tea, and not a reflection onthe absolute amount contained in each tea beverage.)

Caffeine-containing Product Type of Product Caffeine (mg/serving)

Tea Green, black, oolong 50mg/190ml serving2

Green (different varieties) 20-45mg/8oz serving3

Black 47mg/8oz serving4

Coffee Brewed (filter or percolated) 100-115mg/190ml serving2

Instant 75mg/190ml serving2

Cola drinks Standard and Sugar Free 11-70mg/330ml can5

'Energy drinks' All types 28-87mg/250ml serving5

Chocolate Bar 5.5-35.5mg/50g bar5


22/26


f 26 17.11.2007 23:06

1. Khokhar S, Magnusdottir SG. Total phenol, catechin, and caffeine contents of teascommonly consumed in the United kingdom. J Agric Food Chem. 2002 Jan30;50(3):565-70.2.Gray J (1998). Caffeine, coffee and health. Nutrition and FoodScience 6:314-319.3. Unpublished data4. USDA National Nutrient Database for StandardReference, Release 17 (2004)5. Ministry of Agriculture, Fisheries and Food (MAFF)(1998). Survey of caffeine and other methylxanthines in energy drinks and othercaffeine containing products (updated). Food Surveillance Information Sheet No. 144(No. 103 revised). London.Source: Tea Council Fact Sheet, http://www.teacouncil.co.uk/

What is a safe intake of caffeine?

The safety of caffeine consumption remains a topic of major debate in the researchliterature. To our knowledge, no studies have shown problems with caffeine consumptionof less than 75 milligrams per day. Most studies showing potentially problematic effectsof caffeine consumption have focused on intakes above 200 milligrams. In addition,there appears to be a significant difference in people's sensitivity to caffeine. Peoplesensitive to caffeine may wish to drink a decaffeinated green tea or, since approximately80% of the caffeine is released in the first infusion, simply infuse the tea for 45 secondsin hot water, then pour off the liquid. Add more hot water and steep again. This method

removes most of the tea's caffeine but little of its flavor and aroma.

At least two beneficial components in green tea-its catechins and the amino acidL-theanine-lessen the impact of its caffeine. When green tea is brewed, its caffeinecombines with catechins in the water, reducing the caffeine's activity compared to coffeeor cocoa. In addition, L-theanine, which is only found in tea plants and somemushrooms, directly stimulates the production of alpha brain waves, calming the bodywhile promoting a state of relaxed awareness.

Green Tea and Drug Interactions

The tannins in green tea may decrease the absorption and thus the activity of the

following drugs: atropine, Cardec DM, codeine, ephedrine and pseudoephedrine,Lomotil, Lonox, theoplylline, aminophylline, and warfarin.

The caffeine in green tea may interact with the following drugs heightening their effectsto dangerous levels: ephedrine and pseudoephedrine, theophylline, aminophylline.

Green Tea and Iron Absorption

Due to their high tannin-content, teas, including green tea, have been shown to preventiron absorption. While this effect is helpful in persons with too much iron, consumingseveral cups of green tea daily may not be a good idea for persons deficient in iron orsusceptible to iron deficiency.

Limit Green Tea Consumption During the First Trimester of Pregnancy

According to a study published in the March 2005 issue ofCancer Research, ECGC, acatechin present in green tea in amounts about 5 times higher than in black tea, inhibitsthe enzyme dihydrofolate reductase (DHFR), which cancer cells need to be able to grow,and which is a well recognized target of anti-cancer drugs.

Scientists decided to look at ECGC after they realized the green tea catechin looks a lotlike the cancer drug methotrexate, which prevents cancer cells from making DNA byinhibiting the DHFR enzyme. They discovered that ECGC kills cancer cells in the sameway as the drug.

Although ECGC binds strongly to DHFR, which is essential in both healthy and cancerouscells, it does not bind as tightly as methotrexate, so its side effects on healthy cells areless severe than those of the drug.


23/26


f 26 17.11.2007 23:06

ECGC's binding to DHFR may also explain why women who drink large amounts of greentea around the time they conceive and early in their pregnancy may have an increasedrisk of having a child with spina bifida or other neural tube disorders.

Women are advised to take supplements of folic acid when trying to conceive and duringthe first trimester (the first 3 months) of pregnancy because it is during this time periodthat the baby's neural tube is developing. Folic acid helps ensure normal developmentand protects against spina bifida by enabling the production of the enzyme DHFR. While

a cup or two of green tea is unlikely to pose a problem, drinking large amounts of greentea could decrease the activity of DHFR, increasing risk of neural tube defects.

Nutritional Profile

Introduction to Food Rating System Chart

The following chart shows the nutrients for which this food is either an excellent, verygood or good source. Next to the nutrient name you will find the following information:the amount of the nutrient that is included in the noted serving of this food; the %DailyValue (DV) that that amount represents (similar to other information presented in thewebsite, this DV is calculated for 25-50 year old healthy woman); the nutrient density

rating; and, the food's World's Healthiest Foods Rating. Underneath the chart is a tablethat summarizes how the ratings were devised. Read detailed information on our Foodand Recipe Rating System.

Green tea0.07 ounces

2.00 grams

0.00 calories

Nutrient Amount

DV

(%)

Nutrient

Density

World's Healthiest

Foods Rating

World's HealthiestFoods Rating Rule

excellent DV>=75% OR Density>=7.6 AND DV>=10%

very good DV>=50% OR Density>=3.4 AND DV>=5%

good DV>=25% OR Density>=1.5 AND DV>=2.5%

References

Adhami VM, Siddiqui IA, Ahmad N, Gupta S, Mukhtar H. Oral consumption of green tea polyphenols inhibitsinsulin-like growth factor-I-induced signaling in an autochthonous mouse model of prostate cancer. Cancer Res.2004 Dec 1;64(23):8715-22. PMID:15574782.Aneja R, Hake PW, Burroughs TJ, Denenberg AG, Wong HR, Zingarelli B. Epigallocatechin, a green teapolyphenol, attenuates myocardial ischemia reperfusion injury in rats. Mol Med. 2004 Jan-Jun;10(1-6):55-62.PMID:15502883.Azam S, Hadi N, Khan NU, Hadi SM. Prooxidant property of green tea polyphenols epicatechin andepigallocatechin-3-gallate: implications for anticancer properties. Toxicol In Vitro. 2004 Oct;18(5):555-61.PMID:15251172.Baek SJ, Kim JS, Jackson FR, Eling TE, McEntee MF, Lee SH. Epicatechin gallate-induced expression of NAG-1 isassociated with growth inhibition and apoptosis in colon cancer cells. Carcinogenesis. 2004 Aug 12; [Epub aheadof print]. PMID:15308587.Bastianetto S, Yao ZX, Papadopoulos V, Quirion R. Neuroprotective effects of green and black teas and theircatechin gallate esters against beta-amyloid-induced toxicity. Eur J Neurosci. 2006 Jan;23(1):55-64.PMID:16420415.BBC Health News. Green tea 'may protect the heart. 2005/02/28,http://news.bbc.co.uk/go/pr/fr/-/1/hi/health/4298403.stm.Chen D, Daniel KG, Kuhn DJ, Kazi A, Bhuiyan M, Li L, Wang Z, Wan SB, Lam WH, Chan TH, Dou QP. Green teaand tea polyphenols in cancer prevention. Front Biosci. 2004 Sep 01;9:2618-31. PMID:15358585.Chen JH, Tipoe GL, Liong EC, So HS, Leung KM, Tom WM, Fung PC, Nanji AA. Green tea polyphenols prevent

toxin-induced hepatotoxicity in mice by down-regulating inducible nitric oxide-derived prooxidants. Am J ClinNutr. 2004 Sep;80(3):742-51. PMID:15321817.Choi YB, Kim YI, Lee KS, Kim BS, Kim DJ. Protective effect of epigallocatechin gallate on brain damage aftertransient middle cerebral artery occlusion in rats. Brain Res. 2004 Sep 3;1019(1-2):47-54. PMID:15306237.Chow HH, Hakim IA, Vining DR, et al. Modulation of human glutathione s-transferases by polyphenon e


24/26


f 26 17.11.2007 23:06

intervention. Cancer Epidemiol Biomarkers Prev. 2007 Aug;16(8):1662-6. PMID:17684143.Coimbra S, Castro E, Rocha-Pereira P, Rebelo I, Rocha S, Santos-Silva A. The effect of green tea in oxidativestress. Clin Nutr. 2006 Oct;25(5):790-6. Epub 2006 May 15. PMID:16698148.Coimbra S, Santos-Silva A, Rocha-Pereira P, Rocha S, Castro E. Green tea consumption improves plasma lipidprofiles in adults. Nutr Res. 2006 Nov;26(11):604-7.Devine A, Hodgson JM, Dick IM, Prince RL. Tea drinking is associated with benefits on bone density in olderwomen. Am J Clin Nutr. 2007 Oct;86(4):1243-7. PMID:17921409.Donovan JL, Chavin KD, Devane CL, Taylor RM, Wang JS, Ruan Y, Markowitz JS. Green tea (Camellia sinensis)extract does not alter cytochrome p450 3A4 or 2D6 activity in healthy volunteers. Drug Metab Dispos. 2004Sep;32(9):906-8. PMID:15319329.

Eckert RL, Crish JF, Efimova T, Balasubramanian S. Antioxidants regulate normal human keratinocytedifferentiation. Biochem Pharmacol. 2004 Sep 15;68(6):1125-31. PMID:15313409.Ensminger AH, Ensminger, ME, Kondale JE, Robson JRK. Foods & Nutriton Encyclopedia. Pegus Press, Clovis,California 1983.Fassina G, Vene R, Morini M, Minghelli S, Benelli R, Noonan DM, Albini A. Mechanisms of inhibition of tumorangiogenesis and vascular tumor growth by epigallocatechin-3-gallate. Clin Cancer Res. 2004 Jul15;10(14):4865-73. PMID:15269163.Gardner EJ,

Documents

WHFoods_ Green Tea