Green Tea decreases the risk of breast cancer according to a meta-analysis of studies

Dec 01, 2005

Researchers at the Cancer Center, University of Minnesota, in Minneapolis, analyzed 13 studies on the possible protective effects of Green Tea or Black Tea against breast cancer. The evidence regarding Black Tea was incomplete and confusing. However, the research shows a definite decreased risk in developing breast cancer with Green Tea and those women with the highest intake of Green Tea versus the lowest level of intake had a 22% decreased risk of developing all types of breast cancer. The study is published in the November 25th, 2005 issue of the journal Carcinogenesis.

Commentary by Jerry Hickey, R.Ph.

On May 31st, 2005 we published a different meta-analysis of Green Tea studies and decreased risk of breast cancer. In that meta-analysis the risk of developing breast cancer dropped a staggering 56% when comparing a high level of Green Tea consumption with the lowest level in a group of case control studies, and an 11% drop in cohort studies. The risk of a recurrence of breast cancer dropped by 25% for all stages, however the drop in risk of a recurrence of breast cancer was 44% decreased risk of recurrence if it was an early stage of breast cancer (stages I and II).

Green Tea Polyphenols protect mice from skin cancer caused by the sun

Researchers at the Skin Diseases Research Center, University of Alabama at Birmingham, and at the Veterans Administration medical Center at Birmingham state that Green Tea polyphenols show promise as anticancer agents and may prevent the development of skin cancer caused by the suns ultraviolet B radiation. In this study young female hairless mice were split into two groups, one group received plain drinking water and the second group received Green Tea Polyphenols in their drinking water. Both groups were exposed to high levels of ultraviolet B radiation 3 times a week for 24 weeks (a long time in the life of a young mouse). Compared to the mice on plain drinking water the incidence of skin cancer dropped 35% in the Green Tea Polyphenol in drinking water group, the incidence of multiple tumors dropped by 63%, and the growth of the cancerous tumors decreased by 55%. Additionally, the Green Tea Polyphenols reduced levels of matrix metalloproteinases - enzymes that are important to the growth and spread of cancer; they break down the connective tissue between cells allowing the cancer to grow and spread more easily. The Green Tea Polyphenols increased the level of cancer cell executioners known as Caspases, and decreased levels of growth factors that allow cancer to flourish. Additionally, the Green Tea Polyphenols improved the levels of cancer fighting immune cells in the skin. The study is published in the December 2005 issue of the Journal of Nutrition, the journal of the American Society for Nutrition.