Green Tea: Lesson 6 Combating Cancer - Part 2

Green Tea Antioxidants To The Rescue

We are fortunate to have antioxidants to protect us from dangerous free radicals, especially singlet oxygen. Found in abundance in fruits, vegetables and grains, these natural substances are powerful weapons against cancer, heart disease, stroke, aging and many other deadly conditions. The antioxidants neutralize the rampaging singlet oxygen and other free radicals, stabilizing them so that they no longer have the urge to “steal.” The antioxidants not only prevent the body from the damaging effect of free radicals, they can also protect each other from being oxidized.

Polyphenols are powerful antioxidants found in green tea, garlic, fruits, potatoes and some varieties of nuts. They are especially effective because they work against cancer during both the initiation and activation stages. During the initiation stage they help neutralize carcinogens to prevent them from “hijacking” healthy cells. During the activation state, the polyphenols can actually stop some forms of cancer in their tracks by preventing cancer cells from turning into tumors.

There are many types of polyphenols, including caffeic acid, chlorogenic acid, and ellagic acid, but the catechins – the polyphenols unique to green tea – may be the strongest and most remarkable of all.

Catechins were discovered when curious epidemiologists in the 1970s wondered why people living in Japan’s Shizuoka Prefecture had much lower rates of cancer than other Japanese (including stomach cancer, the country’s leading cause of death). Their interest was further aroused by a comparison of the lung cancer rates in Japan to those of the United States. It seems that the Japanese smoked nearly twice as many cigarettes as Americans, but only had about half the amount of lung cancer. Not only that, the average Japanese person outlived the average American by 7.2 years.

Wanting an answer to the question as to whether or not green tea protected against lung cancer, scientists at the Naylor Dana Institute for Disease Prevention in New York gave a green tea solution to a group of mice for two weeks. They then injected the mice with NNK, a potent carcinogen found in cigarette smoke, three times a week for the next ten weeks, while continuing the green tea treatment. A control group received the same injections, but no green tea. After ten weeks, the control group had developed an average of 22.5 lung tumors per mouse. The green tea group only developed an average of 12.2 tumors per mouse. The green tea group received a 45% reduction in cancerous tumors.

Scientists were intrigued by the results. The green tea polyphenols appeared to fight off cancer. The question now, what was the active ingredient driving results? So — they isolated the five major types of polyphenols exclusively found in green tea: gallocatechin (GC), epicatechin (EC), epigallocatechin (EGC), epicatechin gallate (ECg) and epigallocatechin gallate (EGCg). GC, EC, EGC or EGCG — which one or which mix was responsible for fighting off cancer?

Repeating the NNK-green tea experiment on mice, using each catechin separately, the scientists discovered that the most powerful polyphenol, the one that reduced the greatest percentage of tumors (30%), was epigallocatechin gallate (EGCg). Many scientists now agree that EGCg has the highest level and broadest spectrum of cancer preventing and fighting activity.