Women who had the highest intake of soy had a 29 percent reduced risk of death and a 32 percent decrease in the risk of cancer recurrence compared to those who ate less than 5.3 grams of soy per day.
"There was a linear response, and we found the higher the intake, the lower the mortality, up to 11 grams of soy protein," Shu said, adding that after 11 grams daily the benefit leveled off, but didn't decline.
Eleven grams of soy translates to about one-fourth of a cup of tofu each day, she said.
Both Shu, and Dr. Gina Villani, chief of hematology/oncology at The Brooklyn Hospital Center in New York City, said it's important to note that Chinese women tend to get their soy from natural sources, such as tofu, edamame or unsweetened soy milk, instead of the processed types of soy foods that many Americans eat, such as sweetened, flavored soy milk or soy-based protein bars.
"The take-home lesson is that whole foods are what we need to eat more of," said Villani. "Try to stay away from the processed stuff. Don't bulk up on soy milk or soy candy bars."
Shu also pointed out that Chinese women may be replacing unhealthier food choices, such as red meat, with soy. In an accompanying editorial in the same issue of the journal, experts from the U.S. National Cancer Institute noted that the average daily soy intake for people living in China makes up 10 percent or more of their daily protein intake.
Both Shu and Villani advise against loading up on soy supplements, as these haven't been proven to be beneficial, and Villani said it's unclear if such high levels of soy could cause harm.
And, Villani added, "supplements don't replace food. We haven't even begun to understand the interactions between nutrients in food and the body. Soy as a bean may react different than soy from a candy bar in the body."'/>"/>
All rights reserved