Previous studies have suggested that this antioxidant may protect against breast cancer and other cancers, but this research has been limited, and the mechanism behind these effects isn't clear.
Researchers say the results suggest that green tea's anticancer effects may be largely because of its high content of EGCG, which helps the body's cells from becoming damaged and aging prematurely.
Behind Green Tea's Anticancer Effect
In the study, presented this week at the Experimental Biology 2008 conference, researchers examined the effects of the green tea antioxidant on several indicators of breast cancer growth in laboratory mice.
One group of the female mice was fed a solution of the antioxidant in water for five weeks while the other received regular drinking water. During the second week of the study, researchers injected both groups with breast cancer cells.
At the end of the study, researchers measured tumor size, weight, and density as well as VEGF protein levels associated with tumor growth.
The results showed that treatment with the green tea antioxidant decreased tumor size by 66% and weight by 68% compared with the control group. Mice fed the antioxidant also had significantly lower density of small blood vessels within tumors and VEGF protein levels.
Researcher Jian-Wei Gu, of the University of Mississippi Medical Center in Jackson, says the green tea antioxidant may work against breast cancer by suppressing blood vessel growth in breast tumors as well as slowing the proliferation and migration of breast cancer cells.