+ Reply
Log in or Register to participate in these discussions
Soy and breast cancer
JMS
10 Posts

Not sure if this has been discussed before but I was treated for an estrogen positive breast cancer and am getting mixed messages about soy and phytoestrogens. The surgeon told me flat out “no soy at all” and the dietician at the cancer centre is saying “up to three servings of soy per day” - very confusing

11 Replies
Runner Girl
2320 Posts

Hi @JMS

I was told NO by my oncologist. I try to avoid soy, flax and all phytoestrogens. I figure after all I went thru with treatment why risk it. I'm on an estrogen blocker for a reason.

Runner Girl

@JMS When I had the first meeting with the Pharmacist to go over the do's and don'ts about Letrozole, soy was mentioned. There was not enough studies done to know how soy would react with Letrozole. She asked if I was a vegetarian, no I am not. There may be some products that I eat which has soy but I don't think too much.

@JMS - It's challenging when you get mixed messaging from different healthcare providers on your team.

I thought you might find this info helpful: Eating well after breast cancer | Canadian Cancer Society.

Take Care,

Lacey

JMS
10 Posts
Lacey_Moderator‍ thanks for the link. I also attended a workshop put on by Wellspring that had the same info - up to 3 serving a day of Soy (real stuff not soy protein isolate) isn't supposed to be harmful for estrogen + breast cancer and could potentially help if you are post menopausal. The presenter said the surgeon was going on out of date info. I haven't had anything with Soy for over a year because of the comments from the surgeon (I was vegetarian) and now don't know what to do. I'm still really fearful of doing anything that might cause a recurrence.

JMS

I can understand why you are concerned and don't to do anything to put your health in jeopardy.

You might find it helpful to contact our Cancer Information Helpline for help locating some research studies on the topic that can help further inform your decision. You can reach them at 1-888-939-3333.

Here are a couple of the references for that info with links to the studies:

References

de Glas NA, Fontein DB, Bastiaannet E, Pijpe A, De Craen AJ, Liefers GJ, Nortier HJ, et al . Physical activity and survival of postmenopausal, hormone receptor-positive breast cancer patients: results of the Tamoxifen Exemestane Adjuvant Multicenter Lifestyle study. Cancer. 2014: http://onlinelibrary.wiley.com/doi/10.1002/cncr.28783/pdf.

World Cancer Research Fund International & American Institute for Cancer Research. Continuous Update Project Report: Diet, Nutrition, Physical Activity and Breast Cancer Survivors. 2014: www.wcrf.org/sites/default/files/Breast-Cancer-Survivors-2014-Report.pdf.

I hope this helps,

Lacey

Faith1
824 Posts

@Runner Girl

Why no flax? I am taking it for fiber and to keep my cholesterol in check. I was told Letrozole can make cholesterol go up. I thought it was a good thing?

Runner Girl
2320 Posts

@Faith1

Yes, letrozole and anastrozole can make your cholestrol go up. Have you had yours checked? Is it going up? I take psyllium fiber in the form of metamucil.

Did you know that flax is estrogenic? You might want to consult with your oncologist to find out if they are ok with you taking it.

I was told no soy, well flax is equally if not more so estrogenic in the human body. My cancer is estrogen driven. I'm on an estrogen blocker for a reason. Therefore I have chosen not to add any estrogen to my body in the form of parabens, soy and flax.

Runner Girl

PeggyNL
21 Posts
Runner Girl‍ this is all very confusing. I too have an estrogen driven cancer (lobular breast) and am on a hormone blocker. I was told in the past couple of years by a couple of sources (cancer clinic dietician, diabetes nutrition specialist) that studies have shown that eating products with soy are not harmful as the estrogen is destroyed during the process of digestion, and even if not, the amount of foods containing phytoestrogens you'd need to consume to be harmful would be immense. It seems not all are on the same page if you have been told something different. I avoided soy products for many years after first being diagnosed but will have edamame or tofu now and then - still not eating much of it though.

Reminds me of when I was first diagnosed and wondered if my weight lifting would contribute to an increased risk of lymphadema. Couldn't get an answer.....but now we know that kind of weight bearing exercise is good for you! Information changes of course as new studies etc are done - but it sure can be confusing!!
Runner Girl
2320 Posts

Hi @PeggyNL

I agree there are many mixed messages about phytoestrogens and estrogen driven breast cancer.

I prefer to err on the side of caution, as I don't really know if they cause a problem or not. I just figure why take the chance, I'm on an estrogen blocker cause my body has too much of it. It's my choice because the evidence is not conclusive one way or the other.

Runner Girl

JMS
10 Posts

Hi @Peggy and @Runner Girl

According to the information from Wellspring phytoestrogen is found in soy, flax, oats, rice, barley, chickpeas, lentils and a whole host of other plant based foods. They say it's a weaker estrogic and is better than the stuff our bodies make.

I've been reading the links posted by @Lacey_Moderator and am thinking that there are no "absolutely for sure" answers, you just have to do what feels right.

elle29
782 Posts

I love Soy milk over Oat milk wondered too . Had read not to eat Tofu . But really how much in these parts per million over since you started can this affect you . I think a Oncology Dieticien be best to ask . Or check out your Provincial Cancer Web site she referred me to look at for other dietary concerns like diahrea diet with cancer .

+ Reply