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Soy products and aramatose inhibitors

primekprimek Broken HillMember Posts: 5,347
I was wondering if there is any research about issues with soy products with aramatose inhibitors?  I know the cancer council recommend moderation for women on tamoxifen but are there issues with femera? I have a soy cappacino most days as seemed to have developed an issue with milk since chemo. Few places sell almond milk options but most have soy.

Any info greatly appreciated.



  • DeanneDeanne Sunshine Coast QldMember Posts: 2,126
    Hi Kath,
    I asked my oncologist about this when I first started on Femara. Her view was that anything in moderation is ok. A single soy cappacino sounds like moderation to me! 
    Deanne xxx
  • GlemmisGlemmis Member Posts: 316
    The Memorial Sloan Kettering Hospital has an app on herbs you can download & there is some information there on soy & tamoxifen but not aramotose inhibitors. But it is also said soy is a contraindication for hormone receptor cancers.
  • AfraserAfraser MelbourneMember Posts: 2,956
    My understanding was that it was best to stay away from soy (I am on Femara too) but, as with all things, that depends on the quantity/regularity.  There's been research on cow's milk too, which isn't entirely heartening but low fat seems the way to go there, and any impact may also depend on whether you are eating a lot of cheese, yoghurt, ice cream etc as well as drinking milk on a daily basis, or just having a small amount of one. Problem with so much research is the degree to which something is a significant or insignificant factor. A chat with your oncologist will settle any concerns. 
  • Pauline_BCNAPauline_BCNA Melbourne, VICMember Posts: 14
    edited March 2017
    Hi there,
    I'm on the policy team here at BCNA. Thanks for raising this question about dietary soy and aromatase inhibitors.

    At present it is still not clear if eating a diet high in phyto-oestrogens (soy products) is safe for women who have, or have had, breast cancer. For women with oestrogen receptor positive breast cancer who are taking an aromatase inhibitor such as anastrozole, it is still unclear whether eating soy foods or taking soy supplements will block or enhance the actions of the aromatase inhibitors. Results of scientific studies are contradictory, with some studies showing that dietary soy can interfere with the actions of aromatase inhibitors and other studies showing that soy can possibly enhance aromatase inhibitors, such as anastrozole.

    As Cancer Council NSW advises, moderate consumption of soy foods, as part of an overall healthy eating plan, is unlikely to have any harmful effects. In the US, the positions of the American Cancer Society and the American Institute for Cancer Research are similar: that soyfoods can be safely consumed in moderation by women with breast cancer. It is best however to avoid high doses of soy products, such as soy supplement tablets or powders. 

    You can also read more about Cancer Council Australia's response to soy and breast cancer on their iheard site, here.
    Note they do not mention aromatase inhibitors, only tamoxifen. I am currently following up with them on any evidence surrounding aromatase inhibitors and soy. I will keep you all posted.

    If you have any questions or concerns about soy food consumption and your breast cancer treatments, it is always best to speak with your oncologist.

    I hope this is helpful!

    Best wishes
    Pauline McLoughlin

  • AfraserAfraser MelbourneMember Posts: 2,956
    Many thanks Pauline
  • UnicornkissesUnicornkisses Central CoastMember Posts: 402
    So glad you brought that up. I was wondering how soy affects women with ER+Ve cancers.
    I am lactose intolerant and drink quite a bit of soy milk, yogurt and other products.
    I had planned to take that up with my Oncologist next visit.
    Have switched to Lactose free for the time being.
  • KarenhappyquilterKarenhappyquilter Member Posts: 236
    I am a vegetarian and often eat tofu (which is made from soy) and have a small amount of soy milk at breakfast time every day.  I wasn't aware of this concern with eating it when taking tamoxifen before so this is helpful.  A moderate amount in a diet is ok they say, but how much is that I wonder?  Gosh diet is difficult sometimes.  Karen 
  • primekprimek Broken HillMember Posts: 5,347
    Thanks Pauline. Will await feedback.
  • Pauline_BCNAPauline_BCNA Melbourne, VICMember Posts: 14
    Cancer Council Australia does not have further info on this issue - other than what I have stated above.
    I hope this information has been helpful.
  • melclaritymelclarity Member Posts: 3,415
    Hey Kath! Gee thats a tough one, I heard to most likely not have Soy, I actually drink Almond Milk and am happy with that. The thing is when I did my Rehab Course at Epworth Freemasons, I had an ARRAY of Professionals who were apart of it, Social Worker, Psychologist, Occupational Therapist, Physiotherapist and Dietician. We had like mini lectures and the MOST interesting one was on Diet/Nutrition and Cancer. They were very clear about that all studies are MINORITY Studies in terms of foods and therefore have no bearing on BC. This did stun me a little but then explained why there is always something coming up we cannot eat LOL...all minority. She said the key factor is a healthy balanced diet and moderation. She also talked about Sugar and that purely was about obesity and how that leads to other problems. Very eye opening. I also believe too everything in moderation and the thing is there are NO groups of women that fit any categories at all..this is why we are such a mix of age, race, gender, backgrounds, diets and fitness. It doesnt discriminate period. :) Hugs Melinda xo
  • Cate64Cate64 Member Posts: 446
    @primek my oncologist told me to steer clear of all plant based estrogen / phytoestrogen .... so I swapped immediately from soy to almond milk & then go a skinny milk if almond is not available as I would rather live with the side effect of an upset belly from having regular milk than the alternative. Cate  
  • HarleeHarlee Member Posts: 106
    Last year I participated in The Women's Wellness After Cancer Program www.wwacp.com.au and it quoted 2 studies from the American Institute for Cancer Research which indicated that eating moderate amounts of soy food (1 or 2 servings daily) is safe for breast cancer survivors. WWACP actually encouraged participants to increase their soy intake and recommended 2 serves per day as this would supposedly lead to increased health benefits eg reduced menopausal symptoms and a lower incidence of cardiovascular disease. 
    A serve was listed as 1 cup of soy milk, 2 slices of soy and linseed bread, 35g of soy breakfast cereal, 100g of tofu or 5g of linseeds. The benefit is only from consuming food sources not from supplements taken as powders or pills. 

    I felt uncomfortable with this as my oncologist had said that I didn't need to avoid soy but recommended limiting myself to 1 serve per day. I chose to follow his advice. 

    I have copied the links to the studies quoted - hopefully they work.

  • primekprimek Broken HillMember Posts: 5,347
  • Cate64Cate64 Member Posts: 446
    Gee it gets confusing all these studies when they contradict what you hear, see, read elsewhere. I was told I needed to avoid them because my cancer was ER+ & so plant based estrogens/phytoestrogens were out.. 
  • primekprimek Broken HillMember Posts: 5,347
    Yes...latest tesearch of 6,000 women now says otherwise. Check out last Fridays update. 
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