30 Health Benefits Of Green Tea

Camellia sinensis plant was originally cultivated in East Asia. Today, it grows throughout Asia and parts of the Middle East and Africa. Archeological records show that people have been steeping Green Tea leaves for over 5,000 years! Globally, tea ranks second only to water in overall beverage popularity. Green tea has been used as a medicine in China for at least 4,000 years. The Chinese have known about the medicinal benefits of Green Tea since ancient times, using it to treat everything from headaches to depression. In traditional Chinese and Indian medicine, practitioners used Green Tea as a stimulant, a diuretic (to help rid the body of excess fluid), an astringent (to control bleeding and help heal wounds), and to improve heart health. Other traditional uses of Green Tea include treating gas, regulating body temperature and blood sugar, promoting digestion, and improving mental processes. People in Asian countries more commonly consume green and oolong tea while black tea is most popular in the United States. Hundreds of millions of people drink tea, and studies suggest that Green Tea, in particular, has many health benefits.

Plant Description of Green Tea

Camellia sinensis grows as large as a shrub or tree. Green, black, and oolong tea are all derived from the leaves of the same Camellia sinensis plant. Green tea is prepared from unfermented leaves, the leaves of oolong tea are partially fermented, and black tea is fully fermented. The more the leaves are fermented, the lower the polyphenol content and the higher the caffeine content. Green tea has the highest polyphenol content while black tea has roughly 2 – 3 times the caffeine content of Green Tea.

Apart from caffeine, which gives tea its characteristic taste, bitterness and stimulating effect, Green Tea is rich in a group of chemicals, called Catechin Polyphenols (Commonly known as Tannins which contribute to the bitter taste and astringency) like Catechin, Epicatechin, Epicatechin Gallate (ECG), Epigallocatechin Gallate (EGCG), Pro-Anthocyanidins etc. An average cup of Green Tea contains 50 – 150 mg polyphenols (antioxidants). They are also known as Flavonoids and are very powerful antioxidants. Flavonoids, together with some amino acids are responsible for the flavour of Green Tea. Further, it also contains Amino Acids like Theanine, Butyric Acid & Liganin; Xanthine Alkaloids such as Adenine, Dimethylxanthine, Theobromine, Theophylline and Xanthine; Pectin (also found in fruits); saccharides (sugar), Chlorophyll and Triterpene Saponins. Some vitamins like vitamin A, vitamin B1, vitamin B2, vitamin B3, vitamin C and vitamin E are also found in Green Tea.

Health Benefits of Green Tea

Green Tea for Cancer

Several population-based clinical studies have shown that both green and black teas may help protect against cancer. For example, cancer rates tend to be low in countries such as Japan where people regularly consume Green Tea. However, it is not possible to know for sure from these population-based studies whether Green Tea actually prevents cancer in people. Early clinical studies suggest that the polyphenols in tea, especially Green Tea, may play an important role in the prevention of cancer. Researchers also believe that polyphenols help kill cancerous cells and stop them from growing. The secret of Green Tea lies in the fact it is rich in catechin polyphenols, particularly epigallocatechin gallate (EGCG). EGCG is a powerful anti-oxidant: besides inhibiting the growth of cancer cells, it kills cancer cells without harming healthy tissue. The US National Cancer Institute reports that in epidemiological studies and the few clinical trials of tea for the prevention of cancer, the results have been inconclusive. The institute “does not recommend for or against the use of tea to reduce the risk of any type of cancer.

Green Tea for Bladder Cancer

Research by a multi-departmental team from UCLA has produced valuable insights into how Green Tea extract might be capable of acting against the invasive growth of bladder cancer tumors. Green tea extract has been shown, via a mechanism that affects cell movement, to target cancer cells while leaving healthy cells alone. For cancer to grow and spread, the malignant cells must be able to move. Cancer cells are invasive and Green Tea extract interrupts the invasive process of cancer. In effect, the Green Tea extract may keep the cancer cells confined and localized, where they are easier to treat and the prognosis is better. Only a few clinical studies have examined the relationship between bladder cancer and drinking tea. In one study that compared people with and without bladder cancer, researchers found that women who drank black tea and powdered Green Tea were less likely to develop bladder cancer. A follow-up clinical study by the same group of researchers revealed that people with bladder cancer, particularly men, who drank Green Tea had a better 5-year survival rate than those who did not.

Green Tea for Breast Cancer

Japanese scientists at the Saitama Cancer Research Institute discovered that there were fewer recurrences of breast cancer, and the disease spread less quickly, in women with a history of drinking five cups or more of Green Tea daily. Clinical studies in animals and test tubes suggest that polyphenols in Green Tea inhibit the growth of breast cancer cells. In one study of 472 women with various stages of breast cancer, researchers found that women who drank the most Green Tea had the least spread of cancer. It was especially true in premenopausal women in the early stages of breast cancer. They also found that women with early stages of the disease who drank at least 5 cups of tea every day before being diagnosed with cancer were less likely to have the cancer come back after they finished treatment. However, women with late stages of breast cancer had little or no improvement from drinking Green Tea. Some believe that there is no clear evidence one way or the other about Green Tea and breast cancer prevention. In one very large study, researchers found that drinking tea, green or any other type, was not associated with a reduced risk of breast cancer. However, when the researchers broke down the sample by age, they found that women under the age of 50 who consumed 3 or more cups of tea per day were 37% less likely to develop breast cancer compared to women who didn’t drink tea.

Green Tea for 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 Cancer in 2003 found that when Green Tea was given along with a diet high in omega 6 fat (in the form of corn oil), the amount of pro-inflammatory compounds produced in the colon (5-lipoxygenase, leukotriene A4 hydrolase, and leukotriene B4) was significantly lower, as was the resulting number of pre-cancerous colon cells (aberrant crypt foci). Green tea consumption even reduced the amount of abdominal fat produced in the animals that received it compared to controls. 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 to develop colorectal cancer compared to infrequent Green Tea drinkers. Women who continued to drink Green Tea regularly throughout the study fared even better, reducing their risk of colorectal cancer by 57%.

Green Tea for Esophageal cancer

Studies in laboratory animals have found that Green Tea polyphenols inhibit the growth of esophageal cancer cells. However, studies in people have produced conflicting findings. For example, one large-scale population-based clinical study found that Green Tea offered protection against the development of esophageal cancer, particularly among women. Another population-based clinical study found just the opposite — Green Tea consumption was associated with an increased risk of esophageal cancer. In fact, the stronger and hotter the tea, the greater the risk. In 1994 the Journal of the National Cancer Institute published the results of an epidemiological study indicating that drinking Green Tea reduced the risk of esophageal cancer in Chinese men and women by nearly sixty percent. University of Purdue researchers recently concluded that a compound in Green Tea inhibits the growth of cancer cells. However, more research seems needed before scientists can recommend Green Tea for the prevention of esophageal cancer.

Green Tea for Stomach cancer

Laboratory studies have found that Green Tea polyphenols inhibit the growth of stomach cancer cells in test tubes, but studies in people have been less conclusive. In two studies that compared Green Tea drinkers with non-drinkers, researchers found that people who drank tea were about half as likely to develop stomach cancer and stomach inflammation as those who did not drink Green Tea. However, a clinical study with more than 26,000 men and women in Japan found no association between Green Tea and stomach cancer risk. Some studies even suggest that Green Tea may increase the risk of stomach cancer. More clinical studies are underway to see whether Green Tea helps reduce the risk of stomach cancer.

Green Tea for Lung Cancer

If you smoke, or if you must be around smokers and are exposed to second hand smoke, drinking Green Tea can offer some protection against lung cancer. A human pilot study recently confirmed the protective effects of Green Tea against lung cancer seen in cell culture and animal studies. The study, published in the November 2004 issue of Molecular Nutrition and Food Research evaluated the effect of Green Tea (5 cups per day) on 3 heavy smokers (>10 cigarettes a day) and 3 individuals who had never smoked. When the study subjects were drinking Green Tea, DNA damage caused by smoking was decreased, cell growth was inhibited, and cellular triggers for apoptosis (cell suicide) in abnormal cells increased. Another larger four month study of heavy smokers involving 100 women and 33 men found that levels of urinary 8-hydroxydeoxyguanosine, a marker of free radical damage to DNA, dropped significantly in individuals drinking decaffeinated green but not black tea. A recent analysis of 22 studies that probed the correlation between high tea consumption and reduced risk of lung cancer concluded that by increasing your daily intake of green (not black) tea by two cups may reduce the risk of developing lung cancer by 18%.

Ovarian Cancer

Green tea consumption has been shown to enhance survival in women with ovarian cancer. In a study published in the November 2004 issue of the International Journal of Cancer, women with ovarian cancer who drank at least 1 cup of Green Tea daily had a 56% lowered risk of death during the 3 years of the study compared to non-tea drinkers. A laboratory study of human ovarian cancer cells published in the September 2004 issue of Gynecologic Oncology explains why: EGCG not only suppresses the growth of ovarian cancer cells, but also induces apoptosis (cell suicide) in these cells by affecting a 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 tea each day may significantly lower a woman’s risk of ovarian cancer. Each additional cup of tea per day was associated with an 18% lower risk of ovarian cancer.

Pancreatic cancer

In one large-scale clinical study researchers compared Green Tea drinkers with non-drinkers and found that those who drank the most tea were less likely to develop pancreatic cancer. This was particularly true for women — those who drank the most Green Tea were half as likely to develop pancreatic cancer as those who drank less tea. Men who drank the most tea were 37% less likely to develop pancreatic cancer. However, it is not clear from this population-based study whether Green Tea is solely responsible for lowering pancreatic cancer risk. More studies in animals and people are needed before researchers can recommend Green Tea for the prevention of pancreatic cancer.

Green Tea for Prostate Cancer

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 found to promote prostate cancer. Laboratory studies have found that Green Tea extracts prevent the growth of prostate cancer cells in test tubes. In a large clinical study in Southeast China researchers found that the risk of prostate cancer went down with the increasing frequency, duration and quantity of Green Tea consumption. However, both green and black tea extracts also stimulated genes that cause cells to be less sensitive to chemotherapy drugs. People who are undergoing chemotherapy should ask their doctors before drinking green or black tea, or taking tea supplements.

Green Tea for Gallstones and Biliary Tract Cancers

Green tea lowers risk of gallstones and biliary tract cancers, suggests a large population-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 with biliary tract cancer, 1037 persons with gallstones, and 959 randomly selected controls in Shanghai, China. Among women, after taking account of age, education and body mass index, those who consumed at least one cup of tea each day for at least 6 months had a 27% reduced risk of 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 tea consumption, but the drop in risk was not considered statistically significant.

Skin cancer

The main polyphenol in Green Tea is epigallocatechin gallate (EGCG). Scientific studies suggest that EGCG and Green Tea polyphenols have anti-inflammatory and anticancer properties that may help prevent the development and growth of skin tumors.

Green Tea improves the Efficacy of Cancer Drugs

In the fight against cancer, Green Tea polyphenols are team players, helping cancer-killing drugs do their job. In a study published in the October 2004 issue of the Journal 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 used cancer drugs, doxorubicin, to retain the drug, which could then destroy them. According to a study published in the August 2004 issue of Cancer Letters, another compound in Green Tea, the amino acid theanine, reduces the negative side effects of doxorubicin by increasing the level of one of the body’s most important internally produced antioxidants, glutathione, in normal tissues in the liver and heart—but not in tumors.

Green Tea for 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). Clinical studies that look at populations of people indicate that the antioxidant properties of Green Tea may help prevent atherosclerosis, particularly coronary artery disease. In both atherosclerosis and cancer, cell growth and proliferation is central to the disease process. In therosclerosis, 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.

Green Tea 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 1/2 cup to 2-1/2 cups per day, and 65% less among those consuming more than 2-1/2 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 those, 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.

Green Tea 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.”

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 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.

Green Tea for Liver disease

Population-based clinical studies have shown that men who drink more than 10 cups of Green Tea per day are less likely to develop liver problems. Green tea is just one of many foods that cleanse the liver. Green tea also seems to protect the liver from the damaging effects of toxic substances such as alcohol. Animal studies have shown that helps protect against liver tumors in mice. Results from several animal and human studies suggest that one of the polyphenols in Green Tea, known as catechin, may help treat viral hepatitis, an inflammation of the liver. In these studies, catechin was used by itself in very high amounts. It is not clear whether Green Tea, which has a lower concentration of catechins, would have the same benefits. Besides, 10 cups of Green Tea a day could cause problems because of the high level of caffeine consumed. Ask your doctor about the best way to include Green Tea in your treatment.

Green Tea Protects against Kidney Disease

An animal study published in the January 2005 issue of Pharmacological Research suggests yet another beneficial effect of Green Tea consumption: the prevention of kidney dysfunction in persons who must take powerful immunosuppressant drugs, for example, after an organ transplant. One such drug, cyclosporine A, while a very effective immunosuppressant, also markedly elevates the production of free radicals highly toxic to the kidneys. In this study, rats given Green Tea as their drinking water along with cyclosporine A produced far fewer damaging free radicals than rats given plain water. In addition, a number of other indicators of kidney function (serum creatinine, blood urea nitrogen, uric acid and urinary excretion of glucose) were significantly better in rats given Green Tea.

Another animal study published in May 2004 in the Annals of Nutrition & Metabolism explains why. Diabetic rats given Green Tea catechins and then exposed to a kidney-damaging drug, streptozotocin, produced less than half the amount of superoxide radicals (a particularly damaging type of free radical) compared to diabetic rats on a catechin-free diet. As a result, a cellular waste product formed by free radical damage to fats, lipofuscin, was almost 200% higher in the diabetic rats who did not receive Green Tea catechins compared to those who did.

Green Tea for Arthritis

Green tea may also be useful in inflammatory diseases, such as arthritis. Research suggests that Green Tea may help arthritis by reducing inflammation and slowing the breakdown of cartilage. A study by Cleveland’s Western Reserve University concluded that drinking four or more cups of Green Tea per day could help prevent rheumatoid arthritis, or reduce symptoms in individuals already suffering from the disease.

Green Tea for Diabetes

Green tea has been used traditionally to control blood sugar levels. Animal studies suggest that Green Tea may help prevent the development of type 1 diabetes and slow the progression once it has developed. This may be due to the fact that it regulates glucose in the body. In people with type 1 diabetes, their bodies make little or no insulin, which helps convert glucose or sugar into energy. Green tea may help regulate glucose in the body. A few small clinical studies have found that taking a Green Tea extract daily lowered the hemoglobin A1c level in people with borderline diabetes.

Green Tea Builds Bones

Researchers at the University of Tokyo have shown drinking Green Tea may significantly increase bone mineral density. Australian researchers report that bone mineral density (BMD) is 2.8% greater in tea drinkers than non-drinkers.

Green Tea for Brain Tumors in Children

Green tea’s ability to inhibit telomerase may also translate into help for children with the most 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 January 2004 issue of Neuro-oncology, investigators found that telomerase activity was at least five times higher in children with these brain tumors than in normal brain cells and that EGCG strongly inhibited telomerase activity in a dose-dependent manner.

Green Tea for de-intoxicating

Green tea is the best cure to get rid of hangovers and fatigue caused by consumption of alcoholic beverages and lack of sleep due to late night parties. A big glass of Green Tea with lemon will banish hangover fully. Green tea with Lemon juice is a very good and popular remedy to cut effect of alcohols effect instantly.

Green Tea for Dental health

This is yet another benefit from Green Tea. It triggers contraction in muscles and tissues and tones up muscles and skin. Even if you do not wish to drink Green Tea, a mere mouthwash with this daily will cause sufficient contraction in gums to keep them firm and tight on teeth and thus prevent loosening and falling of teeth for long. One small study found that drinking Green Tea helped prevent dental cavities. More studies need to be done. Green tea can even help prevent tooth decay! Just as its bacteria-destroying abilities can help prevent food poisoning, it can also kill the bacteria that causes dental plaque.

Green Tea for immunity

Green tea may act as an overall immune booster. Chemicals in Green Tea have been used to reduce colds, flu and even genital warts. Some studies on laboratory animals even show promising evidence that Green Tea can slow the ageing process and even keep us alive longer. Researches show that people who regularly drink Green Tea do not fall prey to common bacterial and viral infections easily, and even if they do, it is far less frequently than those not consuming it. The message is clear. Green Tea boosts immunity.

Green Tea for Inflammatory Bowel Disease (IBD)

Green tea is a well-known digestive stimulant. Green tea may help reduce inflammation associated with Crohn’s disease and ulcerative colitis, the two types of IBD. If Green Tea proves to help prevent colon cancer, it would also help those with IBD because they are at a higher risk for colon cancer.

Prevents Osteoporosis and Periodontal diseases

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

Green Tea as a Stimulator

The main reason behind acceptance of any kind of tea, be it green, black or white, by human civilizations and its popularity, is its stimulating effect. This effect, again, is due to the Caffeine and Tannins present in it. Caffeine & Tannins, despite their adverse effects on health in the long run, are very good as stimulants. That is why; a cup of tea makes you feel fresh and highly energized. Tea is ideal to counter fatigue, laziness, sleepiness and lack of energy and to improve blood circulation. No doubt it is so popular with any kind of professionals, housewives and students.

Green Tea as a Stamina & Endurance Booster

You can prove this yourself. Just have a cup of hot Green Tea after rigorous exercise and within no time you will be ready for a few more sets. Further, it effectively counters muscular pain due to over exercise of muscles.

General Advice

“Taken altogether, the evidence certainly suggests that incorporating at least a few cups of Green Tea every day will positively affect your health,” says Diane McKay, PhD, a Tufts University scientist who studies antioxidants. “It’s not going to cure anything and it shouldn’t be consumed as a drug, but it can complement the rest of the diet.” General Advice: Eat your fruits, vegetables, grains, seeds, and nuts — and go ahead, drink as much Green Tea as you want.

Dosage of Green Tea

Pediatric

Green tea has not been studied in children, so it is not recommended for pediatric use.

Adult

Depending on the brand, 2 – 3 cups of Green Tea per day (for a total of 240 – 320 mg polyphenols) or 100 – 750 mg per day of standardized Green Tea extract is recommended. Caffeine-free products are available and recommended.

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 per cup, stir and serve hot, or use half the amount of hot water (or twice the amount of tea), allow the tea to brew and cool, then combine half and half with fruit juice, such as peach, pineapple or papaya. Blend and pour over ice.
Make Green Tea chai by brewing Green Tea in hot vanilla soy milk. Top with a dash each of cinnamon, black pepper, ginger and allspice.

How to Brew a Cup of Green Tea

Producing the perfect cup of Green Tea is a tricky process. If not handled properly, those same polyphenols that provide health benefits can ruin the flavor, making the tea taste “grassy.” It’s particularly important not to overbrew Green Tea. While it’s best to follow the manufacturer’s instructions for each variety of Green Tea, here are some general instructions:

Use one tea bag, or 2 – 4 grams of tea*, per cup.
Fill a kettle with cold water and bring to a boil.
After unplugging the kettle, allow it to stand for up to 3 minutes.
Pour the heated water over the tea bag or tea, and allow it to steep for up to 3 minutes. If using a tea bag, remove the bag.
Allow the tea to cool for three more minutes.
*One to two teaspoons, depending on the variety of Green Tea you are brewing.

Side effects of Green Tea

To date, the only negative side effect reported from drinking Green Tea is insomnia due to the fact that it contains caffeine. However, Green Tea contains less caffeine than coffee: there are approximately thirty to sixty mg. of caffeine in six – eight ounces of tea, compared to over one-hundred mg. in eight ounces of coffee. Green tea has a little amount of caffeine which causes insomnia, nausea and frequent urination. Other Risks: Long term consumption and in greater quantities may give rise to problems such as insomnia, restlessness, annoyance, irritability, headaches, hypertension, abnormal heart-beats, loss of appetite, spasms, constipation and acute addiction to it. Many a time it is seen that people who are addicted to it do not feel motion and suffer from acute constipation, irritation and lack of concentration on anything in absence of Green Tea.

Possible Interactions:

If you are being treated with any medication, you should not drink Green Tea or take Green Tea extract without first talking to your health care provider.

Category: HERBAL TEAS