Soy, Green Tea Combo Shows Promise in Breast Cancer

BOSTON--Researchers out of Harvard Medical School reported a mixture of soy and green tea inhibited breast cancer growth. Findings were reported in the Jan. 1 edition of the International Journal of Cancer (108, 1:8-14, 2004) (http://www3.interscience.wiley.com/cgi-bin/jhome/29331?CRETRY=1).

The premise of the study was based on the fact that breast cancer is significantly less prevalent among Asian women, whose diets contain high levels of soy and tea. Researchers sought to identify the combined effects of dietary soy phytochemicals and tea components on breast tumor progression in an animal model characterizing MCF-7 androgen-dependent human breast tumors.

Mice with induced tumors were treated with genistin-rich soy isoflavones, soy phytochemical concentrate, black tea, green tea, a soy phytochemical/black tea combo or a soy phytochemical/green tea combo. Alone, genistin-rich isoflavones and soy phtyochemicals led to dose-dependent inhibition of MCF-7 tumor growth. Also, green tea showed more potent anti-breast tumor activity than black tea; a green tea infusion of 1.5 g tea leaf/100 mL water produced a 56-percent reduction in final tumor weight. The soy phytochemical/green tea combo, given as .1 percent of the diet, further reduced final tumor weight by 72 percent. In an analysis of serum and tumor biomarkers, the soy phytochemical/green tea combo also inhibited tumor growth and serum levels of insulin-like growth factor, which can potentially play a role in breast cancer development.