In some animal studies, rodents that were exposed to high doses of compounds found in soy called isoflavones showed an increased risk of breast cancer. This is thought to be because the isoflavones in soy can act like estrogen in the body, and increased estrogen has been linked to certain types of breast cancer.
This of course begs the question “Does soy increase your risk of cancer?”
The variety of study outcomes may reflect influences that differ by the type of soy food, time of life they are consumed, the type of cancer, and individual differences in genetics, gut microbiota or overall diet. Consistent findings from population studies indicate no increased risk for breast cancer survivors who consume soyfoods.
This of course begs the question “Is soy linked to cancer?”
Yes, soy mimics estrogen and estrogen is linked to some hormonally active cancers, but that does not mean that soy itself is linked to cancer. “There has been concern over the years regarding soy consumption and development or recurrence of breast cancer, and the basis for this concern is isoflavones, a compound in soy with a similar chemical.
Do soy foods cause or help prevent cancer?
Soy might lower the risk of other cancers. Soybeans, soy nuts and edamame all contain fiber. And a diet high in fiber may lower your risks for several cancers, including colorectal cancer. Studies among prostate cancer survivors indicate that eating soy foods may lower PSA levels.
Does soy really cause breast cancer?
The idea that soy can lead to breast cancer began with several animal studies conducted in the 1990s. These studies showed that the compound in soy (called isoflavones) stimulated the growth of tumors in mice implanted with estrogen-receptor positive breast cancer cells.
Studies show that a lifelong diet rich in soy foods reduces the risk of breast cancer in women . This protective effect is less dramatic for women who eat less soy or who start eating soy later in life. Soy contains protein, isoflavones and fiber, all of which provide health benefits.
“The reduction of ER-a sites by the consumption of fermented, whole soy, not isolates from soy, like isoflavones, results in reducing circulating estrogen levels in women. This will slow down the growth of ER-positive cancers, not promote their growth.
Is soy OK to eat with breast cancer?
Prostate and breast cancer rates are lower in Asian countries where soy foods are a regular part of an overall healthy diet. Soy in natural food form such as tofu, edamame and soy milk is safe for consumption, even for people with a cancer diagnosis. Cancer patients do not need to eliminate all sources of soy food from their diet.
Does eating soy increase estrogen production?
Soy protein-containing foods, like tofu, textured vegetable protein and edamame, do not significantly increase estrogen levels in either men or women. Soy may have mild, beneficial anti-estrogenic or estrogenic effects, depending on your time of life.