Existing epidemiologic evidence indicates that soyfood intake reduces risk of ovarian but only limited research has been conducted. To examine this relationship in detail, Chinese investigators conducted a case-control study involving 1,000 women (mean age, 59) from Guangzhou, the capital city of Guangdong Province of southern China.
Information on habitual consumption of soyfoods, including soybean, soymilk, fresh tofu, dried tofu, and soybean sprout, was obtained face-to-face from participants through a validated and reliable semi-quantitative food frequency questionnaire. Isoflavone intakes were then estimated using the USDA nutrient database. The ovarian cancer patients consumed on average much less soy than their healthy counterparts, 75.3 grams per day versus 110.7 grams per day. When divided women into tertiles, according to the amount of soy consumed, those in the highest intake group (≥120 grams per day) were 71% (odds ratio, 0.29; 95% confidence interval 0.20 to 0.42) less likely to have ovarian cancer than were women in the lowest intake group (<61 grams per day). Isoflavone intake was also inversely associated with the ovarian cancer risk, with significant dose-response relationships being noted.
Lee Andy H., Su Dada, Pasalich Maria, Tang Li, Binns Colin W., Qiu Liqian, Soy and isoflavone intake associated with reduced risk of ovarian cancer in southern Chinese women, Nutrition Research (2014), doi: 10.1016/j.nutres.2014.02.005.