Many US women are not sure if eating soy based food could help them prevent breast cancer. Earlier studies have shown that soy products could help prevent cancer. Soybean-based food are an excellent protein source that is low in calories and saturated fat. On the contrary doctors do not recommend the consumption of soy products for women who are prone to breast cancer called estrogen-receptor-positive breast cancer. Because soybean-based food contain compounds called isoflavones.
In some studies isoflavones are found to be able to mimic the hormone estrogen and develop tumor growth. In an animal study at the Georgetown Lombardi Comprehensive Cancer Center in Washington, D.C., have revealed the reason behind the capability of soy products to prevent and fuel its spread. By giving a set of rats soybean isoflavones throughout their lives, the rats had improved immunity against cancer. The particular one type of soybean isoflavone given to those rats was called genistein.
But for a set of rats that was not given the soybean isoflavone until after developing breast cancer did not have the same immune response to kill cancer cells. Instead, these rats became at a higher risk of developing breast cancer over again. Even after their tumor was removed.
The study may explain why Asian women have five times lower breast cancer risk than the women in the US. Asian women consume high amounts of soybean-based food in their entire life than women in the US. More than 200,000 US women are diagnosed with breast cancer. Most of them have estrogen-receptor-positive breast cancer, a data from the Centers for Disease Control and Prevention. Tamoxifen is one of the most common drug that acts to reduce estrogen's ability to promote cancer growth.
In the animal study, all of the sets of rats were given tamoxifen to kill the cancer. The researchers found that rats that were raised on genistein had seven percent of breast cancer recurrence after the tamoxifen treatment. However, for the rats that was given genistein after the breast cancer development had 33 percent recurrence rate.
It is not clear why genistein has this kind of effect. But it may be related to the body’s immune system being activated by the isoflavone. The immune system may be recognizing it as a nutrient from its longtime consumption, said study senior author Leena Hilakivi-Clarke. According to the Science Daily, researchers suggest that breast cancer patients should consume soybean products after diagnosis, but do not start them without previous consumption of genistein.
According to the Live Science, The research says that consuming soy products are good ways to prevent cancer, and not to cure it. Consuming soy products would be more helpful if women did not develop any form of cancer yet. However, consuming soy products, during breast cancer treatment would not cure the cancer, but rather encourage the development of tumor.