The study found that a cathechin in green tea, epigallocathechin gallate (EGCG), was more than 100 times as effective at neutralizing free radicals as vitamin C, and 25 times more powerful than vitamin E. Both are well known antioxidants. EGCG also topped other antioxidants, such as BHA, BHT, and Resveratol. Antioxidants are thought to prevent cellular damage that leads to certain diseases - especially cancer.

Mitscher indicated that green tea contained, by far, the highest concentrations of active EGCG. He also stated that the daily consumption of green tea needed for antioxidant effect has not been established, but pointed to previous studies in China and Japan, where people customarily  drink four (or more) cups per day. It has not been determined whether one cup per day is sufficient.

GREEN TEA CATECHIN COULD INHIBIT TUMOR GROWTH 

In June of this year, Dr. Jerzy Jankun and associates from the Medical College of Ohio published a study in the science journal Nature that offered a possible explanation as to how green tea may work to prevent  certain cancers.

The group demonstrated that one of the major ingredients in green tea, a catechin known as epigallocathechin -3 gallate (EGCG) acts as a good inhibitor of urokinase, an enzyme crucial for cancer growth. Further,  green tea was compared to a well known urokinase inhibitor called amiloride which can be consumed in a maximum dose of 20 mg per day,  whereas a single cup of green tea contains up to 150mg of EGCG. Green tea lovers who consume five or more cups per day are benefiting from very high levels of inhibitor. Previous studies have concluded that  inhibition of urokinase can decrease or even cause complete remission of cancers in mice.

The catechin EGCG is not present in black tea as it is destroyed during the fermentation (oxidation) process of tea manufacture. Herbal teas,  which are not derived from the camellia sinensis plant, also do not  contain any levels of EGCG.

Green tea may inhibit cancer formation in a number of different ways. More research is much needed in this area so that we can gain a better understanding of green teas role in cancer prevention.

GREEN TEA TEST TO BEGIN

Cancer researchers in Texas have won approval from federal regulators to  launch the first human trial studies of green tea as a cancer fighting  agent in the United States. Doctors at the University of Texas M.D.  Anderson Cancer Center, along with colleagues at the Sloan-Kettering  Cancer Center in New York will give doses of green tea to patients whose cancer tumors have been diagnosed as untreatable. 

Numerous lab studies have concluded that green tea inhibits tumor growth and metastases. The new research effort will enable physicians to determine whether green tea actually inhibits the formation and growth of cancerous cells in human patients.

The doses of green tea to be given will be rich in both epigallocathechin (EGC) and epigallocathechin -3 gallate (EGCG). Both seem to be active against human cancer cells.

GREEN TEA DRINKING MAY REDUCE HEART DISEASE

In a study presented at the International Symposium on Physiological and  Pharmacological Effects of tea in 1991, researchers from the National Defense Medical College in Saitama, Japan revealed that total serum  cholesterol levels were reduced in Japanese men who were heavy green tea  drinkers. The study involved 1,306 men aged 49 and 56 years old.  A similar study released released in March, 1995 by the Saitama Cancer  Center in Japan, which studied 1,371 men over forty, came to the same  conclusions. Lowering blood cholesterol is associated with preventing heart disease.

GREEN TEA MAY PROTECT AGAINST ESOPHAGEAL CANCER

Research reported in the June, 1994 issue of the Journal of the National  Cancer Institute, found that Chinese men and women who drink green tea  enjoy a reduced risk of developing esophageal cancer. Green tea is  consumed to a much greater extent in China and other parts of Asia.  Researchers from the National Cancer Institute and the Shanghai (China)
Cancer Institute interviewed nine hundred esophageal cancer patients and 1,500 without the disease. Subjects who drank green tea and avoided burning hot fluids had significantly lower cancer risk.

GREEN TEA COMPONENTS - POLYPHENOLS AND CATECHINS 

Most researchers believe that it is the polyphenols in green tea that  are responsible for the health benefits. More specifically, certain  catechins found in tea are believed to be the most powerful. The  catechins in green tea make up a large percentage of the total amount of  polyphenols. Certain catechins, especially epigallocatechin gallate  (EGCG) are believed to provide the most protection. While the level of polyphenols and catechins in green tea can vary, depending on growing conditions, quality of the leaf, and brewing  methods, the following approximates the amount in a cup of green tea.
The percentages are measured in weight % of extract solids of a green tea beverage.