Statistics showing that women in the US have higher risks of developing breast cancer than women in China or Japan and that breast cancer risks for Asian women that migrate in the US increases over generations, becoming similar to that of US white women, thus suggesting that lifestyle or environmental factors rather than genetics being responsible for this differences, led to a study in order to identify these factors.

597 women with breast cancer and 966 healthy women of Chinese, Japanese and Filipino descent living in San Francisco, Oakland, Los Angeles or Hawaii took part in a research in which their mothers who were also living in the US were questioned about their daughters’ frequency of soy consumption in childhood. By dividing soy intake into thirds and comparing the highest and lowest groups, researches concluded that high intake of soy in childhood was associated with a 58 percent reduction in breast cancer and 20 to 25 percent reduction in the adolescent and adult years. The results were conclusive regardless of race, study site and family history. The study lead investigator, Larissa Korde, M.D., M.P.H., a staff clinician at the NCI’s Clinical Genetics Branch, stated:
“Since the effects of childhood soy intake could not be explained by measures other than Asian lifestyle during childhood or adult life, early soy intake might itself be protective. Soy isoflavones have estrogenic properties that may cause changes in breast tissue. Animal models suggest that ingestion of soy may result in earlier maturation of breast tissue and increased resistance to carcinogens.” Read the rest of this entry »