Research summary
February 2007
Questions raised about soy and breast cancer risk
Summary
There was significant media coverage recently of a Position Statement issued by The Cancer Council NSW entitled Soy, Phyto-oestrogens and Cancer. Phyto-oestrogens are compounds found in plants that may act like oestrogen when they are consumed.
The Cancer Council NSW developed the position statement in response to many inquiries it receives on the topic.
The Cancer Council NSW examined the evidence about the role of soy and phyto-oestrogens;
• in the prevention of cancer in healthy men and women, and
• in stimulating the growth of tumours in people previously diagnosed with cancer.
The Cancer Council NSW Position Statement can be viewed here.
National Breast Cancer Centre comment
To date, studies on phyto-oestrogens in soy products and breast cancer have shown conflicting results. More research is needed before any definitive statements can be made about the role of phyto-oestrogens in stimulating the growth of existing breast cancers or protecting against the development of breast cancer.
Given the lack of conclusive evidence about safe or effective levels of phyto-oestrogen intake at this time, it is difficult to give clear guidance, and moderation in diet would be the most sensible approach.
The National Breast Cancer Centre supports national dietary guidelines that promote a balanced and nutritious diet, which may include soy products. Women who are being treated for or who have had breast cancer may wish to discuss their phyto-oestrogen intake with their surgeon or medical oncologist.