High intake of diets rich in soy foods and isoflavones may contribute positively to the prevention of breast cancer in premenopausal Japanese women.

This study was conducted to determine the effect of high consumption of soybean products on breast cancer risk. Researchers examined the intakes of soy foods, such as tofu (soy curds), and isoflavones, of 167 breast cancer patients and 854 healthy Japanese women. The menopausal status and breast cancer odds ratio of each of the participant in this study was also evaluated.

Researchers observed that increased consumption of soy bean products and isoflavones decreased breast cancer odds in premenopausal women. On the other hand, high intake of soy foods was found to have an insignificant effect on breast cancer risk in postmenopausal women. The findings of this study support the theory that consuming large quantities of soy foods may prevent the development of cancerous cells in the breast of Japanese premenopausal women.