Green Tea and Cancer

Green tea shows promise in cancer prevention research. [6], [7] Green Tea appears to have antitumor properties. [8] Clinical studies have indicated that consumption of Green Tea may reduce the risk of certain types of cancer, including oral cancer [9], prostate cancer [10], and colon, stomach, and rectal cancers. In studies on animals, Green Tea has consistently demonstrated the ability to inhibit the growth of cancer cells in skin, lung, colon, liver and pancreatic cancer. [11] Other research investigated the use of Green Tea as a treatment for cancer in the mammary glands and the colon. [12]

• Green Tea shows promise for types of brain tumors. [13]
  Medulloblastomas are malignant invasive embryonal tumours of the brain that are more commonly found in children. These tumors have a tendency to metastasize in the central nervous system (CNS). Canadian researchers reported that epigallocatechin-3-gallate (EGCG), the major Green Tea polyphenol, can reach the brain following oral intake and could thus act as cancer-fighting agent. The Canadian team concluded that "this naturally occurring Green Tea polyphenol may thus be used as a nutraceutical therapeutic agent in targeting the invasive character of medulloblastomas."
• Green Tea consumption linked to lower cancer risk in smokers [14]
  Researchers from the United States Department of Agriculture reported that people who drink five cups of tea daily are not only likely to improve their cholesterol levels but may also protect against damage from smoking. [15] This was a new and somewhat unexpected find, although many doctors had long suspected a link between Green Tea and cancer prevention.
  
  In a study conducted in the Netherlands, 133 heavy smokers, aged 18-79 years, were given either green tea, black tea, or water for a total of four months. At the end of the study, the smokers in the Green Tea group showed significant increases in plasma and urinary levels of catechins and significantly lower levels of urinary 8-OHdG. Smokers assigned to the black tea group experienced no change in urinary 8-OHdG. Doctors involved in the study concluded, " that regular Green Tea drinking might protect smokers from oxidative damages and could reduce cancer risk or other diseases caused by free radicals associated with smoking." Green Tea has shown promise as a treatment for lung cancer. [16]
• Green Tea as a preventative measure for breast cancer [17] and cervical cancer [18]
  A study of 501 Asian women with breast cancer and 594 Asian women who were cancer free found that Green Tea drinkers showed a significantly reduced risk of breast cancer. The reduction of cancer cases held after adjusting for age, specific Asian ethnicity, birthplace, age at menarche, parity, menopausal status, use of menopausal hormones, body size and intake of total calories and black tea. Researchers noted that compared to women who did not drink Green Tea regularly (i.e., less than once a month), there was a significant trend of decreasing risk with increasing amount of Green Tea intake. [19] Other research on cervical cancer indicates that Green Tea may have more beneficial effects for women. Green Tea appears to inhibit the growth of cancer cells in the cervix.
• Prostate cancer prevention and Green Tea [20], [21]
  Prostate cancer is the most frequently diagnosed malignancy and the second leading cause of cancer-related deaths in American. However, rates for prostate cancer are much lower among Japanese and Chinese populations, leading to speculation that Green Tea consumption in the diet may serve to protect Asian men from the ravages of prostate cancer. Research on the effects of Green Tea and the prostate indicate that this may be the case.
• Bladder cancer
  Animal studies on tumors in the bladder indicate that Green Tea inhibits tumor growth. In one study, 18 of the 28 animals with bladder tumors (64%) were free of tumor growth three weeks after beginning treatment with green tea. [22] Another study showed promise for Green Tea as a preventative treatment for urinary bladder cancer. [23]
• Green Tea and Skin Cancer
  Green Tea may actually help prevent nonmelonoma skin cancer. [24] Research indicates that epigallocatechin gallate (EGCG), a Green Tea catechin, may have antioxidant and sunscreening properties. [25] Still other research has shown that Green Tea polyphenols are photoprotective in nature, and may be used as pharmacological agents for the prevention of solar UVB light-induced skin disorders including photoaging, melanoma and nonmelanoma skin cancers after more clinical trials in humans. [26], [27] Skin cancer is a major health concern in the United States, where over 1 million cases of skin cancer are diagnosed yearly.

Abstracts of Research on Green Tea Extract and Cancer are found in the Research section of this web site.