Natto, a fermented soybean dish of Japan, offers postmenopausal women protection from bone fractures, concludes a new study in The Journal of Nutrition. Studying 24 years of records of 1,417 Japanese women older than 45, researchers found that compared to those women that rarely ate natto, those that consumed one to six 40-gram packs a week had 21 percent fewer fractures and those consuming more than seven packs had 44 percent fewer fractures. Tofu and other soybean products had no effect on fracture risk. With its strong smell and sticky consistency, natto is an acquired taste, but is also one of the few plant sources of vitamin K2, which activates bone-building proteins. Other studies have linked it to healthier gut flora, lower cholesterol and blood pressure levels, and a stronger immune system.