Soy and fava bean both contain genistin, the compound that was proven to be simulative with growing estrogen – positive breast cancer cells and doctors advised women not to eat soy foods.
Nevertheless, recent studies have shown that women with long-term, high-soy diets have lower breast cancer recurrences. Professor Leena Hilakivi-Clarke of Georgetown University discovered that rats with a long-term high-genistein diet responded better to anti-estrogen treatments than control subjects. Also, they were less prone to cancer. She concluded the prolonged consumption of genistein, found in soybeans, actually protects against breast cancer.
While doing her research, she dealt with many contradictory researches as well, investigating the effect of genistein in rats, and she found that T-cells responded more quickly and strategically, overcoming certain defense mechanisms cancer cells use to evade attacks.
This is what Professor Hilakivi-Clarke said: “Results suggest that genistein’s ability to activate anti-tumor immune responses and reduce expression of immunosuppressive mechanisms may explain why lifetime genistein intake reduces risk of breast cancer recurrence.”
PhD student and a member of Professor Hilakivi-Clarke team, Xiyuan Zhang also stated: “It is critical that genistein is consumed well before a tumor develops to program the tumor to exhibit good immune responses.”
Evidence proves that genistein also fights other types of cancer, including brain, colon and for men prostate – actually in rats, for these studies shown cancer fighting in rats. Human and rodents actually metabolize soy in the different way and the results in humans may differ from those in rats.