Study: Childhood Soy Diet Reduces Breast Cancer Risk
Reported March 30, 2009
(Ivanhoe Newswire) — Asian-American women who ate a lot of soy during their childhood are significantly less likely to develop breast cancer than other women, even those who consume a lot of soy in adolescence and adulthood, according to a new study.
Historically, breast cancer rates are four- to seven-times higher among white American women than women in China or Japan, researchers said. But when Asian women migrate to the United States, their breast cancer risk rises over several generations and eventually reaches that of white women, leading scientists to suspect that lifestyle factors rather than genetics are responsible for the international differences.
For this study, researchers interviewed 597 women with breast cancer and 966 healthy women. All of the women were of Chinese, Japanese and Filipino descent living in the U.S. If the women had mothers living in the U.S., the mothers were also interviewed to determine the frequency of their soy consumption in childhood.
High soy intake during childhood was associated with a 58 percent reduction in breast cancer, but a high level of soy intake during adolescence and adulthood was only associated with a 20 to 25 percent reduction.
“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,” the study’s lead investigator Larissa Korde, M.D., M.P.H., of the National Cancer Institute’s Clinical Genetics Branch was quoted as saying.
The researchers cautioned that even though these findings are potentially life changing, additional studies need to be done before doctors start recommending changes to children’s diets.
SOURCE: Cancer Epidemiology, Biomarkers and Prevention, March 2009