Contrary to popular belief, recent research shows that soya consumption does not increase the risk of breast cancer and may even decrease it. Soya contains phytoestrogens, which are plant substances similar to female hormones in the body. These phytoestrogens can attach to oestrogen receptors in the body, blocking the real oestrogen from binding and reducing the stimulation of tissue growth. While studies in mice and rat models have shown variable results, it’s important to note that humans metabolise phytoestrogens differently.
Soya has been found to have a protective effect against cancer in general, particularly lung and prostate cancer. Countries with higher soya consumption, such as Japan and China, have lower breast cancer rates compared to countries with lower soya consumption, like Belgium and France. Soya-containing foods, not supplements, have shown potential protective effects against breast cancer. In contrast, dairy and red meat have been associated with a higher risk of breast and prostate cancer.
- ‘Is Soy Healthy?’ Physicians Association for Nutrition (blog), 19 January 2023. https://pan-int.org/is-soy-healthy/.