Flax Seeds & Breast Cancer Survival: Epidemiological Evidence

Flax Seeds & Breast Cancer Survival: Epidemiological Evidence
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Lignan intake is associated with improved breast cancer survival in three recent population studies following a total of thousands of women after diagnosis.

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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 class of phytonutrients known as 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 of the same purported anti-cancer properties. Since, as we’ve explored, 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.

Well, we just covered the prevention angle, with population-based evidence, in-vitro evidence, and clinical evidence supporting lignans in preventing breast cancer. But, what about for women already diagnosed with the dreaded disease?

Three studies, following a total of thousands of women diagnosed with breast cancer, were recently published to answer that question. The first was from New York, reporting substantially reduced risks of overall mortality, and especially breast cancer mortality, associated with higher lignan intakes in postmenopausal women. “…[A]lthough higher lignan intakes may just be a marker of a diet high in plant foods, specific combinations of foods particularly high in lignans may be necessary to produce effects on mortality-related risk factors to subsequently impact [breast cancer] survival.”

Then there was one out of Italy, in 2012. At surgery, when the women were getting their primary breast tumors removed, they had some blood drawn, and within five years, those that had lower circulating levels of lignans (here in blue) were significantly more likely to die from their cancer coming back than those with more lignans in their bloodstream (in red). They concluded, “lignans might play an important role in reducing all-cause and cancer-specific mortality of the patients operated on for breast cancer.”

And, same thing out of Germany. The latest and largest study to date: “Postmenopausal patients with breast cancer who have high serum [lignan] levels may have better survival.” Here’s the survival curve; the higher the better. Those who had the most lignans in their bodies tended to live the longest, and tended to live the longest disease-free.

So, what should oncologists tell their patients?  “Given this objective evidence that [blood levels of lignans] a biomarker of lignan intake improves breast cancer outcomes, should we declare success and recommend that our patients with breast cancer supplement their diet with flaxseed?” Not based on laboratory and population evidence alone, the editorial concluded; robust clinical evidence is needed—which I’ll cover in the next video.

Please consider volunteering to help out on the site.

Images thanks to calvinfleming via flickr

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 class of phytonutrients known as 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 of the same purported anti-cancer properties. Since, as we’ve explored, 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.

Well, we just covered the prevention angle, with population-based evidence, in-vitro evidence, and clinical evidence supporting lignans in preventing breast cancer. But, what about for women already diagnosed with the dreaded disease?

Three studies, following a total of thousands of women diagnosed with breast cancer, were recently published to answer that question. The first was from New York, reporting substantially reduced risks of overall mortality, and especially breast cancer mortality, associated with higher lignan intakes in postmenopausal women. “…[A]lthough higher lignan intakes may just be a marker of a diet high in plant foods, specific combinations of foods particularly high in lignans may be necessary to produce effects on mortality-related risk factors to subsequently impact [breast cancer] survival.”

Then there was one out of Italy, in 2012. At surgery, when the women were getting their primary breast tumors removed, they had some blood drawn, and within five years, those that had lower circulating levels of lignans (here in blue) were significantly more likely to die from their cancer coming back than those with more lignans in their bloodstream (in red). They concluded, “lignans might play an important role in reducing all-cause and cancer-specific mortality of the patients operated on for breast cancer.”

And, same thing out of Germany. The latest and largest study to date: “Postmenopausal patients with breast cancer who have high serum [lignan] levels may have better survival.” Here’s the survival curve; the higher the better. Those who had the most lignans in their bodies tended to live the longest, and tended to live the longest disease-free.

So, what should oncologists tell their patients?  “Given this objective evidence that [blood levels of lignans] a biomarker of lignan intake improves breast cancer outcomes, should we declare success and recommend that our patients with breast cancer supplement their diet with flaxseed?” Not based on laboratory and population evidence alone, the editorial concluded; robust clinical evidence is needed—which I’ll cover in the next video.

Please consider volunteering to help out on the site.

Images thanks to calvinfleming via flickr

Doctor's Note

For more on breast cancer survival, see:

What about the role of flax seeds in preventing breast cancer in the first place? See my previous video, Flax Seeds & Breast Cancer Prevention. In my next video, Flax Seeds & Breast Cancer Survival: Clinical Evidence, I’ll detail a randomized, double-blind, placebo-controlled, clinical trial in breast cancer patients where flax seeds are actually put to the test.

For more context, also check out my associated blog posts: Treating Sensitive Skin from the Inside OutFlax and Breast Cancer Prevention; and Flax and Breast Cancer Survival.

If you haven’t yet, you can subscribe to my videos for free by clicking here.

4 responses to “Flax Seeds & Breast Cancer Survival: Epidemiological Evidence

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  1. If you happen to follow Caldwell Esselstyn’s version of a whole-food plant-based diet, you’re already supplementing daily with 1TB ground flaxseed for omega 3’s. Since the series on fenugreek as an anti-cancer agent, I added a Tsp of ground fg seed (very bitter to start but maybe I’ve begun to like it) same with the hybiscus and green teas. My question is after you’ve been living like this for several years (20+years vegan, fit/slender pushing 60 no health issues), what should you specifically look for (and look out for) in your blood and other tests — living long-term as a WFPB vegan? Maybe this could be worth a series. Thanks.




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  2. Off topic – just calling attention to a fascinating story in today’s NYT:
    http://www.nytimes.com/2013/04/08/health/study-points-to-new-culprit-in-heart-disease.html?_r=0

    The gut bacteria of omnivores convert the amino acid carnitine in meats into trimethylamine n-oxide, and high TMAO serum levels were predictive of a 3-fold higher risk of heart attack/stroke/death (2.5 fold adjusted) in this paper
    http://content.onlinejacc.org/article.aspx?articleid=1665659

    The diet of vegans evidently doesn’t support the same gut microbiota, so they didn’t produce TMAO, even when given carnitine supplements.




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    1. Darryl: I wanted to thank you for your posts in general. You have supplied some great information to this site. While I have not responded to your posts before, I wanted you to know that I have read your posts and really appreciated them!




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  3. Dr. Greger I’m hoping with Angelina Jolie’s recent disclosure that she had a preventative double mastectomy you could highlight all of your wonderful videos and articles on breast cancer prevention through diet (and perhaps speak to this in a new article?). Women really need this information. Thank you!




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