Flaxseed & Breast Cancer Survival: Clinical Evidence

Flaxseed For Breast Cancer SurvivalBy Michael Greger, M.D. NutrionalFacts.org

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. The incidence of breast cancer is increasing in the Western world and there is an urgent need for such studies.

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, where you can stick a catheter into a woman’s breast and kind of 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, which is a good thing, because it helps stop tumors from hooking up a blood supply. And the same thing happens when you instead add a little under a 1/4 cup of ground flaxseeds to their daily diet. The flaxseed doesn’t seem as powerful as the chemo, but further study was definitely warranted…

And here it is: a randomized, double-blind, placebo-controlled clinical trial of flaxseeds in breast cancer patients. Between the time of first biopsy and surgery, patients were randomized: either the treatment or the placebo group; either a flaxseed-containing muffin or a control placebo muffin.

Why flaxseeds? Again, they’re the richest source of lignans, with levels up to 800 times higher than that of 5 dozen other plant foods tested in the vegetarian diet.

They went all out: the muffins were wrapped up, labeled with numerical code, and the coded muffin packages were then dispensed.

So what happened? Well, muffin compliance was good. (A sentence you don’t often read!) Remember they got a biopsy of the tumor before the study started and then a little over a month later, went in for surgery to get the tumor removed. So they had tumor samples before and after 5 weeks of flax or no flax. 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, which is a marker of cancer aggressiveness and potential for forming metastases and spreading.

They concluded: “Dietary flaxseed has the potential to reduce tumor growth in patients with breast cancer.” And this was just in 5 weeks! “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.”

Michael Greger M.D.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.

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