Doctor's Note

This is the fifth in my five-part series on the latest research on the impact of diet on breast cancer survival. For two videos on what not to eat, see: Breast Cancer Survival, Butterfat, and Chicken, and Breast Cancer Survival and Trans Fat. And soy joins flax seeds as something breast cancer survivors should probably go out of their way to eat; see Breast Cancer Survival and Lignan Intake, and Flax and Fecal Flora. There are many more videos on soy.

Note also that the JAMA study is open access, so you can download it by clicking on the link in the Sources Cited section, above.

For more context, check out my associated blog posts: Breast Cancer Survival and SoyHow Much Soy Is Too Much?Are Bioidentical Hormones Safe?Gerson Therapy for Cancer?How Tumors Use Meat to GrowMushrooms for Breast Cancer PreventionWhy Less Breast Cancer in Asia?Foods That May Block Cancer FormationFlax and Breast Cancer Survival, and Breast Cancer & Alcohol: How Much Is Safe?.

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  • Michael Greger M.D.

    This is the fifth in my five-part series on the latest research on what impact diet has on breast cancer survival. For two videos on what not to eat, see Breast Cancer Survival, Butterfat, and Chicken and Breast Cancer Survival and Trans Fat. And soy joins flax seeds, as something breast cancer survivors should probably go out of their way to eat. See Breast Cancer Survival and Lignan Intake and Flax and Fecal Flora. There are 21 more videos on soy and also hundreds of other videos on more than a thousand subjects. Note that the JAMA study is open access, so you can download it by clicking on the link above in the Sources Cited section.

    • mfravaga

      Thanks for all the great videos

      What about the different types of cancer? Is soy equally healthy for all breast cancer patients,

    • Dear Dr. Greger: with due respect…. please give up ALL soy for human consumption. It’s the wrong bean and it is not for health. Please? Please?

      • Please the fact that Asians have better ”family”’ values and respect for
        life/people? that’s why they suffer less from cancers?

        Try studying German New Medicine by Ryke Hamer. to understand a
        few facts.

        Read: Cancer is not a disease, by Andreas
        and get off SOY/ TVP/ SOY MILK, SOY CHEESE,
        POISON unFood !

        • Sissi

          Soy does not equal soy, it is very important to understand where it is grown and how it is processed and which parts of the soy bean are being used.
          Some companies take this very seriously and would not subject the public with a product that is harmful in any shape way or form!!! Sadly the vast vast majority of Soy grown in the US are GMO, which is harmful for human consumption, that is where the problem starts. The Soybean is an excellent source for amazing nutrients. The Soy products I use have changed my health 180 degrees and saved my mother’s life with cancer!
          Stop spreading unfounded fear and make educated choices, check the sources of your information – people lets use a little common sense!!!!! GMO is bad! Not soy!
          My company grows their own Soy now in order to ensure a safe and pure product. I’ve left my 21 year career to help people take control of their health and build a worldwide business from home, because these products are safe and change lives for the better!

          • lele23

            Nearly all soy foods that use the whole bean (tofu, tempeh, edamame) are nonGMO. Most are organic. Check the labels. The GMO soy grown in the U.S. is for the most part made into animal feed and soybean oil.

    • 4Baccurate

      I am wondering if phytoestrogens in soy would feed estrogen-receptive positive breast cancer cells? Thanks for your excellent talks.

  • patipnuts

    OK. As a DES daughter, when I have soy or flax, I get painful lumps in my breast. I am not the only DES daughter who does not tolerate it. How can that be if it is beneficial? It is supposed to block estrogen with the weaker phytoestrogen. I am 61, long post-meno. Any ideas?

    • DrDons

      I’m not aware of any studies on soy and DES (sons and/or daughters). However the advice I typically give my patients is to avoid foods that cause symptoms unless there is compelling scientific data supporting the benefits outweighing the risks.

    • SOY is not not a health food ! Just do History of SOY . #1 Asians use Glycine Soja and we use/eat Gycine Max…. this is a l961 invention in Sweden in a lab for industrial purposes. and it’s all GMO … so it’s unfit for human consumption.

  • stefanjuhl

    Great info (again). I have not read the studies, so my question is because of ignorance :-)What about the confounders? Is survival better because they substitute meat and dairy for tofu and soy-milk, and the result is due to avoidance of animal-protein, or is it really because of add on with soy products?

    • Toxins

      Soy foods are rich in isoflavones, a major group of phytoestrogens that have been known to reduce the risk of breast cancer. These were the main nutrients in the studies that were attributed to the breast cancer survival.

      • PhytoEstrogens….. please read this:

        scroll down: Menopausal Symptoms, Hot Flushes once our body stops producing high doses of estrogen … why do humanoids try to push/shove it back in? HOT FLASHES are a Toxic body/lifestyle….. hot/fever is to help us sweat those toxic build ups out. It does not mean we need more estrogen or phytoestrogens.

        • Lew Payne

          Sounds like quackery, from a website hosted in Zaire, no less. Its so-called information fails to cite supporting peer-reviewed studies backing its dubious claims. I’ll stick to reproducible scientific evidence for my facts, thanks.

          • George

            *.za is South Africa, not Zaire.

        • The kind of “information” that you are espousing is exactly the kind of nutrition/medical confusion that Dr. Greger is trying to tackle. Just because you find “evidence” to support your beliefs on the internet does not make them true. For a truly evidenced based perspective on soy, I recommend that you watch all of the videos that Dr. G has on soy on this site. Not to be hurtful, but I think it might also be helpful to you to read a little bit about how to critically assess scientific information (especially information found on the internet).

    • No NOt they do not substitute meat and dairy for TOFU. they eat very little tofu and most of it is fermented! Their diet is more Plant Source… not SOY or Soy milk.

      • Nunya Biznez

        incorrect. I had a Japanese room mate. I can assure you the Japanese eat tofu and soy beans UNFERMENTED and use it for menopause too Don’t believe everything you read. Get the info from the horse’s mouth instead :-) The issue is GM soy. It can NOT be compared to organic soy.

      • Bootsie

        I lived in Asian for four years, they eat lots of meat, vegetables, fermented soy bean paste and lots of tofu. Sounds like a lot of guessing here and answers based on assumtpions rather than fact?

  • Michael Greger M.D.

    Please also check out my associated blog post, Breast Cancer Survival and Soy!

    •  This link aims at this page, but I think you meant another page. Also it’s broken.

      • Michael Greger M.D.

         Thank you so much for pointing that out–I’ll correct that. You’ve been such a great help. I really appreciate it!

  • annon2013

    Okay so should I eat soy or not? I had an early diagnosis of breast cancer and had a lumpectomy. Fortunate the little devil did not travel to my nodes and I am doing well for it being the 3rd month after surgery, having just completed radiation and thank goodness no chemo needed. Soy supposedly helps to create estrogen which is what can contribute to the invasive ductile diagnosis. Before my diagnosis I used soy instead of milk and also loved edemame beans and tofu all in moderation.

    Since soy is also said to ease the natural course of menopause hot flashed etc…which I am currently in and will be forced to undergo full steam like it our not due to Tamoxifen. In your respected opinion would drinking a glass of soy milk a day benefit the effects and also help prevent the return of the cells gone mad to my still intact scar bearing breast?  

    • Toxins

      So phytoestrogens and xenoestrogens are not the same thing as many health professionals seem to confuse the two. Consuming soy can significantly help reduce the risk of breast cancer.

    • DO NOT NOT EAT ANY SOY… If you can get Glycine Soja from Asia and use it sparingly as the Asians do… enjoy some and ”fermented only’ Asians do not use soy like Americans do! Then we use the wrong bean ! 98% GMO Glycine Max which is poison to us.

      • Bootsie

        The Asians in Japan and Korea eat tons of tofu, along with meat, vegetables and rice.

  • CelticLass7

    I was diagnosed with stage 1 estrogen receptor positive invasive ductal breast cancer
    4 years ago.  I subsequently underwent a skin-sparing mastectomy.  There was no spread to my lymph nodes, and I had no radiation or chemotherapy.  However, I have been on Tamoxifen for almost 4 years, with instructions to avoid any phytoestrogens, so have been avoiding soy in all forms, flax seeds, pumpkin, sweet potatoes, etc.  Now I’ve been told that I have a slightly elevated cancer marker in a recent blood test (CA 15-3 with a score of 39.1 unit/mL H), and they want to do a bone scan and brain MRI just to be careful.  Everytime I have asked my oncologist about soy I’m told it should be avoided because of it being a phytoestrogen and studies showing that it could increase my chance of recurrence.  Having been a vegan for the past 1-1/2 yrs. it would be a whole lot easier if I wasn’t having to avoid so many healthy foods. 

    As of Nov. 2012, what is your feeling on this matter?  Do you believe it would be more protective for me to just go ahead and eat soy, flax, etc.?  Thank you so much for any opinion you can give me.

    • Guest

      I had bilateral mastectomies 6 years ago. My oncologist told me to stop taking stuff with phytoestrogen. .I have stopped my evening primrose oil since and she has also said not to take flaxseeds. Is it proven that it is harmless now?

    • Yes! avoid all soy products. NOT HEALTH FOOD AT ALL !

  • Dolly Warden

    The quality of the soy product should also be considered. Organic and non-GMO soy products should be the one ones acceptable.

  • Ruth

    You better research this more. Soy is not healthy for women in general

  • Dear Dr. Gregor:

    Thank you for your valuable research relating to optimal health, however Re: your question, “What more do we need to know?” It is important you know several things::

    1. I lived in Southeast Asia for nearly ten years and Asians consume soy, tofu, soy products, etc. as a CONDIMENT rather as the main dish in a full meal as is advocated by soy product manufacturers here in the U.S. re: everything from soy bacon and sausage to other soy products mimicking flesh-based foods we are advised to avoid.

    2. There is a substance in soy that must be removed to make it palatable for human consumption. Asian soy removes this substance via natural means whereas Western grown soy uses chemcials to do so.

    3. Asian soy–except that area where Monsanto has taken over–is naturally grown whereas approximately 98% of American-grown-soy is Genetically Engineered.

    4. And finally, as per Doctor T. Colin Campbell’s findings in the China Study, anytime one consumes over 7-10% concentrated protein in the diet– whether animal OR plant based– disease starts to set in. Animal products are worse due to other contanminants however CONCENTRATED PROTEIN is the overall disease culprit.

    I hope you will consder the above information and so advise your many followers as to that which might better suit them regarding the consumption of soy to avoid cancer and other diseases.


    Gerry Coffey

    “Do Good, Feel Good! Do Bad, Feel Bad! LIFE: It’s That Simple!”
    –Anonymous ;-)

    Gerry Coffey, CAJA: Court Appointed Juvenile Advocate

    Health Educator/Councilor/Global Media Liaison, IVU

    Coffey Break: A Healthy Alternative:

    Recipient: Int’l. Vegetarian-of-the-Year-Award, Bangkok, Thailand, 2006

    • Christine

      You mention “The China Study” above but your information is incorrect. The study did NOT show plant based protein causing any issues. See page 6 where it says “What type of protein did not promote cancer, even at high levels of intake? The safe proteins were from plants, including wheat and soy.” and then the book goes into the studies that repeatedly showed plant based proteins are not at issue. There is no mention anywhere in the book of “concentrated protein” as you mention above. To me “concentrated protein” means it is not from a natural, whole, plant based food and I would definitely avoid those (e.g. soy protein isolate) but again, that is not mentioned in the book.

    • Bootsie

      Your reply makes the most sense. It is true many countries do not grow food that is loaded with poisons. So you can not compare the wheat, soy, etc grown where they do not allow so much chemical and GMOs.

  • JesseWeiss

    Thank you for this. I was diagnosed several years ago with early stage breast cancer and had the area removed. There was also a lump in my other breast that was being closely watched. I was a large dairy consumer at the time and have since gone vegan — drinking soy milk and eat tofu now and then. My cancer has not returned and the lump in my other breast disappeared, no more have developed and I feel so much healthier. I wish people were warned about how dangerous (and very cruel!) drinking the breast milk of another species is. Luckily I did the research because few doctors are going to tell you this. Thank you Dr. Greger for all your videos and information!

  • Wai

    I have lcis have been take tamoxifen, is it safe to take soy food. Pls advise.tks in advance.

  • Ruth Houston Barrett

    Hi thanks for this amazing site! Great info and presented in an easy to digest form, which is so refreshing. My lingering concern with soy is that I’ve read that the effects of soy may be quite different for women who grew up (through puberty) consuming soy, versus US women who have not. Also, according to articles I’ve read on PubMed, some studies have shown that certain components of soy may be cancer promoting, whereas others are anti-cancer. So I’d love to jump on the soy bandwagon, if only I could feel confident and sort through this conflicting information. I am a breast cancer (triple positive) survivor, dx 3 years ago, and want to do everything I can to be healthy. Would love your take on this!

  • I do stay away from soy.

  • Ruth Houston Barrett

    My own research makes me cautious for women with estrogen-dependent breast cancer. (I’m a survivor of triple positive bc, ending tx in early 2012 with no signs detected since.) There are two factors that many studies do not tease out: one, that estrogen-dependent bc reacts differently than estrogen-independent, especially to soy. Two, women who consumed soy from childhood seem to be far better off than those who only add it later in life, in terms of soy’s protection. I’ve recently been investigating lunasin and the amazing claims and study evidence it is showing, but I remain worried about my specific type of bc (and I didn’t grow up eating soy). Do you have any insights about this? I would tremendously appreciate it!!! Here are links to some of the studies:

  • 4Baccurate

    I recently had a thermogram which showed a pronounced vascular pattern and a lot of breast swelling, after two weeks’ eating a lot of beets and yams, high in phytoestrogens. Would the phytoestrogens in soy milk, or in tofu, cause the same effect?

  • Barbara
  • hsblinder

    I have been treated for stage 3 breast cancer and my surgeon is adamant about not eating soy. I’m conflicted. In your book you encourage soy consumption for prevention of recurrence. All the literature I read also is against soy consumption. Can you explain?