As estrogen is a known risk factor for some forms of breast cancer, there has been some concern that plant-based compounds with weak estrogen-like effects called phytoestrogens may increase the risk of breast cancer in women.
Studies investigating a possible association between phytoestrogens and breast cancer risk have yielded mixed results. Interestingly, some of the best data seems to suggest that some phytoestrogens may actually reduce the risk of breast cancer.
For example, a new German study found that regular consumption of three particular phytoestrogens was associated with a reduced risk of breast cancer in post menopausal women: soy foods (17% reduction) sunflower and pumpkin seeds (34% reduction).
The study consisted of 2,884 postmenopausal women diagnosed with breast cancer and 5,509 age-matched “controls” without breast cancer. Each filled out detailed food-frequency questionnaires and answered additional questions regarding consumption of specific phytoestrogen-rich foods. Each woman’s individual risk factors for breast cancer were also assessed and considered when analyzing the data.
From this study it appears that at least some forms of phytoestrogens may be beneficial, even though they act on some of the same hormone receptors that estrogen normally stimulates. While this may seem counterintuitive, it supports other research that suggests that phytoestrogens are more complex than once thought.
In fact, some believe that phytoestrogens may actually block the effects of estrogen on estrogen receptors within breast cells. We’ll need more research to understand the exact cause and effect of phytoestrogens on breast cancer.
Dr. Robert Wascher