Eating even a modest amount of whole soy-based foods could reduce the risk of hip fractures among postmenopausal women. Researchers at the National University of Singapore reported that women whose daily soy intake from all sources added up to 49.4 grams (about 1.7 ounces) of tofu were 21 to 36 percent less likely to break a hip than women who ate less tofu. The researchers assessed the soy intake of more than 63,000 Chinese men and women who were 45 to 74 years old when they enrolled in the study.    Soy intake didn’t reduce the risk of breaking a hip for the men in the study. But the investigators suggested that bone-protective effect of soy isoflavones (plant chemicals that may act like estrogen) plays a critical role in the bone health of postmenopausal women. They also noted that an earlier study of Chinese women in Shanghai showed a 30 percent reduced risk for hip fractures among those who consumed the highest amounts of soy. Nevertheless, the researchers called for additional studies to confirm and clarify their findings.  The study was published in the Oct. 1, 2009, issue of the American Journal of Epidemiology.