Transcript: Flax Seeds & Breast Cancer Survival: Clinical Evidence
Below is an approximation of this video’s audio content. To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video.
The population data looked so promising that researchers decided to put lignans to the test by feeding women flax seeds—the most concentrated source of lignans—to see what would happen. The incidence of breast cancer is increasing in the Western world, and there’s 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 six weeks, the levels of endostatin within the breast tend to go up—which is a good thing, because it stops tumors from hooking up a blood supply.
And, the same thing happens when you instead add a little under a quarter 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 flax seeds in breast cancer patients.
Between the time of first biopsy and surgery, patients were randomized to either the treatment or the placebo group—either a flax seed-containing muffin, or a control placebo muffin. Why flax seeds? Again, they’re the richest source of lignans, with levels up to 800 times higher than that of five 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, five weeks of flax, or no flax.
Those lucky enough to be randomized in 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 five 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.”
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