For women who have had breast cancer, soy foods are safe and may even be beneficial for some of them, according to a recent study in the journal Cancer. Over the years there have been concerns that the isoflavones in soy, because of their estrogen-like properties, may be risky.
Researchers from Tufts University followed 6,235 American and Canadian women diagnosed with breast cancer for an average of nine years and correlated their post-diagnosis intakes of isoflavones with deaths from any cause. Overall, women who consumed the most isoflavones from their diet had a 21 percent lower death rate than those consuming the least.
However, the benefit was confined to women with hormone-receptor-negative cancers, who account for about 20 percent of cases and have poorer survival rates. There was no effect on survival rates in women who had hormone-receptor-positive tumors or who received hormonal therapy such as tamoxifen.
One caveat: The amount of dietary isoflavones consumed by women in the study was much lower than that consumed by many women in Asia, and it’s not known what effect such higher intakes would have in North American women.
Also see Pros and Cons of Soy Foods.