Sep 10, · It has been our enemy from the beginning; soy causes breast cancer. The Sloan Kettering Study A study conducted by researchers at the Memorial Sloan Kettering Cancer Center and Weill Cornell Medical College found that for many women, adding a small amount of soy to their diets, can cause cancer to grow. Because estrogen can promote the development, growth, and spread of breast cancers, doctors have worried that eating a lot of soy foods or soy isoflavones (which can be taken as a dietary supplement) might worsen the prognosis of women diagnosed with breast cancer.
Any one of these other things could be the reason why soy-eating women have lower breast cancer risk. This means observational studies can't conclusively prove that soy protects against breast cancer. However, these studies are reassuring in affirming that soy foods do not increase breast cancer risk. Jun 12, · “In fact, higher amounts of soy were linked to a lower risk of breast cancer recurrence or death. It may be because people in China who consume larger amounts of soy tend to lead an overall healthier lifestyle.” These studies .
Soy and breast cancer Because natural soy foods contain isoflavones, similar to estrogen, some people fear that soy may raise their risk for certain cancers. This is because estrogen is linked to hormonally-sensitive cancers like breast cancer. Isoflavones, which are found in soy, are plant estrogens. High levels of estrogen have been linked to an increased risk of breast cancer. However, food sources of soy don't contain high enough levels of isoflavones to increase the risk of breast cancer.