Flax and Breast Cancer Survival

October 17, 2013 by Michael Greger M.D. in News with 9 Comments

Flax and Breast Cancer Survival

 A randomized, double-blind, placebo-controlled clinical trial of flaxseeds in breast cancer patients found that flaxseeds appear to have the potential to reduce tumor growth in just a matter of weeks. Scientists believe this is due to a class of phytonutrients known as lignans, which are present in flaxseeds at levels up to 800 times other plant foods.

Lignans can be thought of as the Western equivalent of the isoflavone phytoestrogens found in soy foods popular in traditional Asian diets, as they share many purported anti-cancer mechanisms. Since soy food consumption is associated with both preventing breast cancer and prolonging breast cancer survival, one might expect the same to be found for lignans. In Flaxseeds & Breast Cancer Prevention I covered the population-based, in-vitro, and clinical evidence supporting prevention, but what about for women already diagnosed with the dreaded disease?

Three studies were recently published that followed a total of thousands of women diagnosed with breast cancer. The first study from New York reported substantially reduced risks of overall mortality and especially breast cancer mortality associated with higher lignan intakes in postmenopausal women.

The next population study was out of Italy. At surgery, when the women were getting their primary breast tumors removed, they had some blood drawn; within 5 years those who had lower circulating levels of lignans were significantly more likely to die from their cancer coming back than those with more lignans in their bloodstream. The researchers concluded “Lignans might play an important role in reducing all-cause and cancer-specific mortality of the patients operated on for breast cancer.”

The latest and largest study to date was performed in Germany. Postmenopausal patients with breast cancer who had high blood lignan levels appeared to have better survival, and the higher the better. You can see the survival curve in my 3-min video Flaxseeds and Breast Cancer Survival: Epidemiological Evidence. Those who had the most lignans in their blood lived the longest and tended to live the longest disease free.

The population data looked so promising that researchers decided to put lignans to the test by feeding women flaxseeds, the most concentrated source of lignans, to see what would happen.

One of the ways the chemotherapy drug tamoxifen works is by boosting the levels of angiogenesis inhibitors like endostatin, which is a protein the body makes to try to starve tumors of their blood supply. Using a technique called microdialysis, you can stick a catheter into a woman’s breast and suck out some of the fluid bathing the breast cells. If you give women tamoxifen for 6 weeks, the levels of endostatin within the breast tend to go up, and the same thing happens when you instead add three and a half tablespoons of ground flaxseeds to their daily diet. As you can see in my video Flaxseeds and Breast Cancer Survival: Epidemiological Evidence, the flaxseed doesn’t seem as powerful as the chemo, but the results were so exciting that researchers undertook a randomized, double-blind, placebo-controlled, clinical trial of flaxseeds in breast cancer patients.

Breast cancer patients were randomized into either the treatment or the placebo group; either a flaxseed-containing muffin or a control placebo muffin every day between the time of their first biopsy and surgery. Researchers then had tumor samples before and after about a month of flaxseeds or no flaxseeds. Those lucky enough to be randomized into the flax group saw, on average, their tumor cell proliferation go down, cancer cell death go up, and their c-erbB2 score go down (a marker of cancer aggressiveness and potential for forming metastases and spreading).

The researchers concluded: “Dietary flaxseed has the potential to reduce tumor growth in patients with breast cancer. If the therapeutic index seen in this short-term study can be sustained over a long-term period, flaxseed, which is inexpensive and readily available, may be a potential dietary alternative or adjunct to currently used breast cancer drugs.”

For more on breast cancer survival, see:

What about the role of flaxseeds in preventing breast cancer in the first place? See my video Flaxseeds & Breast Cancer Prevention.

A study similar to this was also carried out in prostate cancer patients: Flaxseed vs. Prostate Cancer.

See Anti-Angiogenesis: Cutting Off Tumor Supply Lines for more on the role diet plays in angiogenesis, the formation of new blood vessels to enable tumors to grow. I also have touched on briefly in Cancer as an Autoimmune Disease and How Tumors Use Meat to Grow: Xeno-Autoantibodies.

This is the final installment of my latest video series on flax. Feel free to check out the role flaxseeds may play in helping diabetes and sensitive skin.

-Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my videos for free by clicking here and watch my full 2012 – 2014 presentations Uprooting the Leading Causes of Death, More than an Apple a Day, and From Table to Able.

Image credit: TipsTimes / Flickr


Tagged , , , , , , , , , , , , , , , , , , , , , ,

Dr. Michael Greger

About Michael Greger M.D.

Michael Greger, M.D., is a physician, author, and internationally recognized professional speaker on a number of important public health issues. Dr. Greger has lectured at the Conference on World Affairs, the National Institutes of Health, and the International Bird Flu Summit, testified before Congress, appeared on The Dr. Oz Show and The Colbert Report, and was invited as an expert witness in defense of Oprah Winfrey at the infamous "meat defamation" trial. Currently Dr. Greger proudly serves as the Director of Public Health and Animal Agriculture at the Humane Society of the United States.

View all videos by Michael Greger M.D.

Related Posts

  • elsie blanche

    Yes, Flax. It seems to work wonders for some women. I just wish (be careful what you wish for) my body didn’t react so poorly/adversely to flax. But speaking of cancer,food, and women, do you have any thoughts on whether or not it is safe to eat olives? Most olives are soaked in salt/brine. There have been issues raised about olives in regards to acrylamide content, as well as olives that have been salted/brined sharing some of negatives of smoked food products and certain fermented veggies (kimchi). Anyone have any thoughts on olives being OK or NOT in a health vegan diet?

    • Toxins

      Olives are ok, the acrylamide content should not be a concern. Acrylamides may be a concern for someone who eats a lot of fried foods or processed foods but for a healthful, whole foods plant based vegan, acrylamide is not an issue.

      Olives can be good in moderation, but they are quite high in sodium so moderation is key.

      • elsie blanche

        Cool. Thank you.

  • lagaya1

    I eat flax seeds daily, but hiding 3 1/2 tablespoons of it in a muffin would be hard to do. That’s a lot of flax!

  • walk-veg

    Are flax seeds beneficial If the breast cancer is estrogen, progesterone and HER2/neu negative, which means the tumor cells are aggressive?

    • walk-veg

      I just realized this question was address by Toxins and Darryl in great detail and expertise about a month ago. The links were very informative. Please forgive the repetition–and again, “thanks”.

  • JB teacher

    I would love to know what adverse affects Nelsie blanche has to fresly ground flax seeds. I have used it for years and avised others to its use and have never received an adverse
    JB teacher

  • jane

    This is another Testimony on how Dr EHOHO cured My Lung cancer Disease Do you need cure to your HIV disease? Do you want to be cure from your cancer disease? Or you want to be free from any type of disease you have kindly contact Dr. EHOHO on, he just cured my breast cancer disease and I’m very grateful to him, he is the only herbalist that can cure you. Or you can contact me on or call +2381040033845 so that I can put you through on how he did it. Thank you all for reading, God bless”

  • Mirabel

    Hello let me share this testimony to the world to hear about him too this man really exit I was Breast Cancer over 9year I have being in medication and I try to look for cure to my problem and I go through internet doctor and I found a tradition doctor named dr.ehoho contacted him for help he give me all his laws and rule that if I get cured I should write about him and that is what am doing now, this man ask for some information about me, which I give him this man cure me from Breast Cancer what a great man thank for your help when he get the information he told me that he is about to work on it 20 to 30 minute this man email me and told me what to do for the curing which I did after all the things needed for the cure is provide the man call me in 45mins later and tell me to go for test what a great day to me I was negative thanks dr.ehoho you can contact him now or call +2381040033845

  • What is the optimal diet for disease prevention?

  • Subscribe to our free newsletter and stay up to date with the latest discoveries in nutrition.
  • This field is for validation purposes and should be left unchanged.