TUESDAY, March 7, 2017 (HealthDay News) — The pros and cons of soy for breast cancer patients have been debated for years.
Now, research involving more than 6,200 breast cancer survivors finds that those who ate the most soy had a lower risk of death from all causes during the nearly 10-year follow-up period.
“We didn’t find any harmful effects of women diagnosed with breast cancer consuming soy in terms of mortality,” said study leader Dr. Fang Fang Zhang. She’s an assistant professor of epidemiology at Tufts University’s Friedman School of Nutrition Science and Policy in Boston.
“Overall, consuming higher levels of soy is associated with a 21 percent reduction in the risk of death compared to women who consumed soy at a lower level,” she said.
Concerns around soy’s “risk/benefit” profile have arisen because the food has estrogen-like compounds called isoflavones. That’s important, experts says, because in so-called hormone-receptor positive breast cancers — the most common tumor type — higher estrogen levels may spur cancer cells’ growth.
But the new study should settle the soy controversy once and for all, said Dr. Omer Kucuk, a professor of medical oncology and director of the Integrative Medicine Center at Emory University’s Winship Cancer Institute, in Atlanta.
He wrote an editorial accompanying the study, which was published online March 6 in the journal Cancer.
Kucuk said the study’s large population is one point in its favor. The new findings also echo the results of a prior study that found higher soy intake lowered the odds of breast cancer’s return.
“When you have decreased recurrence, you have decreased mortality,” Kucuk noted.
“I think now we can say women with breast cancer should not worry about going out to eat edamame, miso soup, tofu and other soy products, and [to] drink soy milk,” Kucuk said.
All of the participants in the new study were enrolled in the Breast Cancer Family Registry, which began in 1995. At the study’s start, the women averaged 52 years of age.
During the study, just over 1,200 of the participants died. Zhang’s team tracked data on all the women’s diets, some obtained even before they had received their diagnosis of breast cancer.