Is soy safe after breast cancer?
There is plenty of confusion over soy and it’s effect on breast cancer. This is understandable given the amount of conflicting information circulating. Here is what breast cancer survivors need to know.
Rates of breast cancer are lower in countries such as China and Japan where soy is consumed at higher levels than the U.S. Whether this can be attributed to the overall increased soy consumption by Asian women, or the fact that Asian girls typically begin to consume soy regularly at an earlier age then their Western counterparts, needs further study. According to a recent article published in the Journal of Nutrition, its possible that moderate consumption of soy ingested earlier in life may have a protective effect later on. It is also possible that a lifetime of soy consumption that begins at an early age may positively change the biology of tumors later on in life.
Another concern revolves around the different types of soy. Soy contains phytoestrogens that can mimic natural estrogen in the body. Asian cultures tend to ingest more of the lightly processed soy products, such as tofu and soy milk; compare this to the American diet, which increasingly contains highly processed types of soy protein as an additive to foods such as cereals, bars and chips.
It’s important to note that the consumption of soy based foods was also associated with other characteristics of a healthy lifestyle, including exercise and high vegetable and fish intake. This also may be contributing to better outcomes for women diagnosed with breast cancer.
One of the more recent studies to examine these questions in breast cancer survivors is the The Shanghai Breast Cancer Survival Study, a large, population-based cohort study of 5042 female breast cancer survivors in China. Women aged 20 to 75 years with diagnoses between March 2002 and April 2006 were recruited and followed up through June 2009. This was the largest study to date to examine the relationship between soy intake, breast cancer recurrence, and survival. These authors concluded that moderate soy intake was safe, and was associated with lower mortality and recurrence among breast cancer patients.
The bottom line: The latest studies seem to show that consuming soy in moderation appears to not have adverse effects for breast cancer survivors. There is no evidence to suggest that supplementing with soy beyond normal dietary habit offers any protective effect for women with breast cancer and is not recommended.
As with everything, talk to your medical providers about your individual needs.