Letter to Editor
Women with certain breast cancer should avoid soy
By Dan Parker
Aug 9, 2007 - 6:59:47 PM

Dear Editor:

I was reading your article recommending eating 'plant foods' to fight breast cancer.   You may want to hold off on recommending soy foods until more research is done because soy products may do more harm than good to some women.  

My wife has HER2 receptor positive breast cancer which is estrogen-based, meaning that high levels of estrogen promote the cancer. Her chemotherapy forced her into early menopause so she was put on Femara, a daily pill that works against certain types of breast cancer by reducing the level of endogenous estrogen. The drug is most effective if the patient is post-menopausal.  

She adopted a vegetarian diet rich in soy products.   Soy products, especially the concentrated forms such as tofu and textured vegetable protein are known to contain extremely high levels of plant estrogens.   I'd have to say that her intake of these plant estrogens was high.  

After about a half-year of being on this diet, she started experiencing what she thought to be symptoms of her monthly cycle returning, (spotting, cramping and bloating).   Blood tests also revealed that her cancer indicator was elevated.   It had previously been in the normal range, (0-39 points), but had gone up to 42, well into the range that could indicate a possible return of her cancer.  

Since that test she has eliminated most, if not all, soy products from her diet. In addition, she has eliminated dairy products from her diet that contain BST, BGH, rBST, rBGH or whatever other production-boosting hormones would be given to milk herds.

As a result, she once again lacks a monthly cycle and her cancer indicator is back to a more comfortable 25 points and her physical symptoms have all but disappeared.  

For women who have been diagnosed with this type of breast cancer, it's been our experience that it's best to avoid ingesting any foods that have high levels of any sort of hormones, plant or animal.   The levels may be cumulative and their effects more pronounced over time.  

We believe that any woman who has been diagnosed with HER2 receptor, estrogen-based cancer may be better off avoiding estrogen from any source.

Thanks,

Dan Parker

Editor’s response:  

Thank Dan for sharing his first-hand experience.   We suggest readers exercise caution when it comes to what should be eaten to fight any type of cancer.    As Dan suggested, women with estrogen-sensitive breast cancer in our opinion should avoid estrogen from both plant and animal sources.   Study results can be very tricky.   One thing we know is that each study serves a purpose.   Flaws are unavoidable and biases are common.

The potential adverse effects associated with soy products because of their phyto-estrogens have been widely publicized. However, readers should also pay attention to other sources of compounds that are similar to estrogen.  

Just reported is a study that shows bisphenol A, which is widely used in clear-plastic bottles such as baby bottles and beverage bottles, dental sealants, compact disc and epoxy resins, may increase risk of breast cancer and prostate cancer in addition to damages to the female reproductive system.  

More importantly, dairy foods may be a significant source of natural estrogens, which according to a Harvard scientist may be 1000 times more powerful than the environmental estrogens.   The U.S. milk is high in natural hormones compared to Mongolian milk.