The incidence rate of breast cancer varies worldwide, with the rate of Japanese and other Asian women only being a third to a half of that for Caucasian women. Recent research has suggested that consumption of phytoestrogen-rich foods may reduce breast-cancer risk. Most epidemiologic studies have involved Asian populations and some studies have shown a substantial reduction in breast-cancer risk (17-73%) in these populations. These results were also observed in countries where the level of consumption of traditional soy foods is low.