Claimed Benefits

>  Reduces high blood pressure.  Drinking green tea represses angiotensin II which leads to high blood pressure.
>  Lowers blood sugar. Green tea polyphenols and polysaccharides are effective in lowering blood sugar.
>  Fights cancer. There have been many studies that have shown that green tea catechins are effective at preventing cancer.
>  Boosts the immune system because of its high concentrations of polyphenols and flavonoids.
>  Green tea antioxidants have been shown to lower cholesterol.
>  Recent scientific research suggests that green tea has potent fat-burning properties.
>  Antioxidants in green tea may prevent and reduce the severity of rheumatoid arthritis 
>  Consumption of white and green tea provides protection against colon tumors
>  Substances in green tea known as catechins can increase the antioxidant capacity of human plasma, which could help reduce cardiovascular disease risk
>  Green tea has also been associated with fighting cavities and slowing down potentially harmful blood clotting.
>  Treatment for liver disease.
>  Drinking green tea lowers total cholesterol levels, as well as improving the ratio of good (HDL) cholesterol to bad (LDL) cholesterol.
>  Helps to fight flu virus.
>  Eases headaches and depression.
>  Strengthens bone density.
>  Aids in digestion by fostering the growth of beneficial bacteria in the intestines.
>  Black and Green teas boost the effectiveness of insulin 15 fold. Tea also improves blood glucose control in nondiadetics.
> 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.
> Researchers found that men who were given a combination of caffeine and green tea extract burned more calories than those given only caffeine or a placebo. This has caused its inclusion in numerous diet aids lately.
> Associations (from epidemiological research) have been made between higher green tea consumption and reduced incidence of cancers of the breast, prostate, stomach, pancreas, colon and lung, but further research is needed to confirm this effect.

The Chinese have known about the medicinal benefits of green tea since ancient times. It has been used as a medicine in China for at least 4,000 years. Green tea is prepared from the steamed and dried leaves of Camellia sinensis, a shrub which grows in eastern Asia. Scientific research in both Asia and the west is providing hard evidence for the health benefits long associated with drinking green tea. The key to the how and why green tea is effective seems to be related to antioxidants, flavonoids, polyphenols and catechins.

Antioxidants bind harmful oxygen-containing molecules in your body called free radicals and peroxides that otherwise could damage your DNA, cell membranes, and other cell components. The process of breaking down food for energy creates free radicals in your body everyday. Naturally occurring antioxidants found in most plants including fruits and vegetables help your body keep free radicals in check.

Flavonoids are nutrient antioxidants found in most plants and many foods common in the human diet. There are 12 types of flavonoids, and one plant species may contain hundreds of different flavonoids. Polyphenol is a broad class of antioxidants including flavonoids and catechins. Catechins are a type of flavonoid contained in the leaves of tea. Catechins are very strong antioxidants, even more powerful than vitamins A, C, E and beta-carotene at combating harmful free radicals and and have far-reaching positive effects on the entire body.

There are four primary polyphenols in green tea and they are often collectively referred to as catechins. These powerful antioxidants have been shown in recent studies to fight viruses, slow aging, and have numerous beneficial effects on health. Free radicals are highly reactive molecules and fragments of molecules that can damage the body at the cellular level leaving the body susceptible to cancer, heart disease, and many other degenerative diseases.

One catechin polyphenol, epigallocatechin gallate (EGCG) is a powerful anti-oxidant. Along with inhibiting the growth of cancer cells, it kills cancer cells without harming healthy tissue. It has also been effective in lowering LDL cholesterol levels, and inhibiting the abnormal formation of blood clots. The latter takes on added importance when you consider that thrombosis (the formation of abnormal blood clots) is the leading cause of heart attacks and stroke.

While green and black tea originate from the same plant, Camellia sinensis, green tea leaves are much less processed because they are not fermented like black tea. Green tea leaves are steamed, which prevents the EGCG compound from being oxidized. By contrast, black and oolong tea leaves are made from fermented leaves, which results in the EGCG being converted into other compounds that are not nearly as effective in preventing and fighting various diseases. Green teas have a more delicate, fresh taste, whereas black teas are often more full-bodied and robust.

Links are being made between the effects of drinking green tea and the "French Paradox." For years, researchers were puzzled by the fact that, despite consuming a diet rich in fat, the French have a lower incidence of heart disease than Americans. The answer was found to lie in red wine, which contains resveratrol, a polyphenol that limits the negative effects of smoking and a fatty diet.  In a 1997 study, researchers from the University of Kansas determined that EGCG is twice as powerful as resveratrol, which may explain why the rate of heart disease among Japanese men is quite low, even though approximately seventy-five percent are smokers.

You will see green tea tablets promoted on the internet and elsewhere these days, primarily as the new weight loss ingredient. We have been unable to find information regarding the comparative health effects between these and the tea itself. We tend to go with the 4,000 years worth of endorsements until we hear more.

Harmful Effects? 

To date, few negative side effects have been reported from drinking green tea. One 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 is available in decaf.

In theory, the vitamin K in green tea could reduce the effectiveness of anticoagulants such as warfarin. But you would have to drink a lot of tea before this could happen. The tannins in green tea can also block the absorption or iron -- a problem in women with anemia

Some people have a hypersensitivity to green tea. Pregnant and breast-feeding women should avoid green tea supplements pending long-term safety studies. Use with caution in people with a history of bleeding or haemostatic disorders.

Dosage

The strong antioxidants, catechins, and flavonoids are in equal amounts in hot and iced green teas. Green teas will vary though, we suggest you refer to the article listed below, to help you choose one. An average 6-oz. cup of green tea contains about 30 mg of caffeine. For comparison, coffee has about 100 mg per cup. Although traditional green tea drinkers prefer not to add anything to their healthful concoction, for those who add milk and sweeteners to green tea, the research findings suggest you are in the clear. Sugars, sweeteners, lemon and milk do not appear to effect the antioxidant levels of green tea polyphenols.

There are a variety of recommended amounts of green tea to take. We have seen from 1 to 10 cups a day recommended. All and all, it is probably safe to plan on drinking four to five cups of green tea per daily. If you're a real devotee, by all means drink more; but whether or not you'll derive added health benefits remains to be seen.

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 "gassy." It's particularly important not to overbrew. 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 (one to two teaspoons, depending on the variety of green tea you are brewing) 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.

Green tea can certainly be recommended as a healthy drink, but there is far less research on green tea supplements, and more research is needed on their safety and efficacy before definite recommendations for their value can be made.

There are numerous interesting articles on the web on this subject. Here are a few:

Antioxidant levels of common teas vary widely (Leaves USGyms)
Tea Believed to Boost Body's Defenses (Leaves USGyms)
Green Tea Can Help Prevent Rheumatoid Arthritis (Leaves USGyms)