Diets rich in phytoestrogens from soy and unrefined grains may lower the risk of certain cancers, like breast and prostate cancer. Studies have looked at how phytoestrogens affect hormones, cell growth, antioxidants, and cancer risk factors. It's unclear if phytoestrogens can be used to prevent or treat cancer. More research is needed to understand their safety and effects on different types of tumors. Consuming soy or soy supplements may have varying effects on cancer risk.