Cancer proofing your diet can be complicated. Especially when there is so much conflicting information out there. That’s why it’s always important to go back to the research literature, instead of relying on popular opinion when it comes to cancer and diet. Recently, several people have asked me about Flaxseeds, breast cancer, ovarian cancer, and uterine or endometrial cancer. Seems that some people are starting to say that combining Flaxseeds with these cancer types is dangerous and should be avoided.

Based on Cancer Research, I completely disagree with the fear around flax seeds with hormone sensitive cancers. Let’s talk about why…

Estrogen Receptors and Flaxseeds

Yes, flaxseeds stimulate estrogen receptors. For some people, that’s enough to completely avoid flaxseeds. But, here’s a shocker…estrogen receptors aren’t all bad! You see, we have two main types of Estrogen Receptors (that we can measure right now), Estrogen Receptor Alpha and Estrogen Receptor Beta

Estrogen Receptor Alpha: linked to increased abnormal cell growth and cancer growth, including breast cancer, endometrial cancer, ovarian cancer, and colon cancer.

Estrogen Receptor Beta: linked to reducing abnormal cell growth, stimulation blocks cancer growth. This receptor site is used to block breast cancer growth via the drug tamoxifen. Natural supplements like melatonin and Flaxseeds also stimulate Estrogen Receptor Beta.

Flaxseeds Could Block Breast Cancer Growth

As far as we can tell in human clinical data, Flax Seeds seem to block breast cancer cell growth. In one study, women ate 25 grams of Flaxseeds daily while waiting for their breast cancer surgery. When their pathology reports were compared to women who didn’t eat flax seeds prior to surgery, they had less aggressive tumors according to pathology reports.

What does that mean? When their breast cancer tumors were looked at under the microscope and in the lab, their tumors were less aggressive and showed more cancer death.

How do I apply this in my clinic? When I see women in my clinic prior to breast cancer surgery, you can bet that we will talk about adding 25 grams of Flaxseeds to their diet! Does that mean it’s a good fit for everyone? Not necessarily. So please talk to your health care team to see if it’s a good fit for you.

Not only that, but in general, a lignan rich diet (such as Flax lignans) have been shown to reduce breast cancer risk.

There are a few rat and mice studies that show that Flaxseeds:

  • block breast cancer growth after rats are exposed to a cancer promoting chemicals
  • could be synergistic with tamoxifen (aka… help make tamoxifen more effective)

Flaxseeds and Prostate Cancer

When it comes to hormone sensitive cancers in Men, such as prostate cancer, flax seeds can be an important diet intervention. One study gave Men 30 grams of flax seeds daily, 30 days prior to prostatectomy (or prostate removal). What they found was a statistically significant reduction in prostate cancer cell growth, also known as proliferation.

Take home message: Men with prostate cancer can start eating flax seeds prior to surgery (if OK’d by their surgeon and cancer care team) and might have better results.

Other Hormone Sensitive Cancers

At this time, we don’t have specific data on flaxseeds and uterine sarcomas or ovarian cancer. But, given Flaxseeds action on Estrogen Receptor Beta, we might assume (for now) that flax seeds could be beneficial for ovarian cancer, endometrial cancer, and uterine cancer.

I hope this helps clears up some of the confusion when it comes to flax seeds and breast cancer, flax seeds and prostate cancer, and flaxseeds with cancer in general. Your comments and questions are always welcomed! I’m here to help.

References:

Clin Cancer Res. 2005 May 15;11(10):3828-35. Dietary flaxseed alters tumor biological markers in postmenopausal breast cancer. Thompson LU1, Chen JM, Li T, Strasser-Weippl K, Goss PE.

https://www.ncbi.nlm.nih.gov/pubmed/15897583

https://onlinelibrary.wiley.com/doi/full/10.1002/ijc.25052

https://www.nature.com/articles/6604175

http://cancerres.aacrjournals.org/content/71/1/51.short

https://www.liebertpub.com/doi/abs/10.1089/jmf.2012.0159

http://cebp.aacrjournals.org/content/17/12/3577.short