Flaxseed Lignans

BCCT plans to write a summary on flaxseed lignans. While our summary is in development, you can visit these sites:

Clinical Practice Guidelines

According to the Society for Integrative Oncology’s 2009 clinical practice guidelines, there is insufficient evidence to rate the effectiveness of flaxseed lignans for helping quality of life or hot flashes.1

Reducing Risk

Reducing the risk of developing cancer or the risk of recurrence

Flaxseed lignans are reported to reduce the risk of some cancers.


Do not heat flaxseed oil, as the heat will damage the oil and form dangerous compounds.2

About Herbs cautions that because flaxseed has phytoestrogenic effects, patients with estrogen receptor positive breast cancer should use flaxseed lignan with caution. However, their summary on flaxseed did not cite any studies to back up this caution. A 2013 review of studies of flaxseed and breast cancer findings:

In vitro, flaxseed metabolites such as ENL [enterolactone] have been shown to interact with estrogen receptors behaving as weak estrogen agonists. While this action may be of concern to women with breast cancer, flaxseed administration appears to have no significant effect on endogenous estrogen levels in the majority of human trials, either in women with cancer or in healthy women. Conversely, studies that do report significant changes cite decreases in serum estrogen levels, suggesting reduced exposure to endogenous estrogen over time with flaxseed consumption. Fabian et al assessed the effect of 50 mg of SDG [a flax lignon precursor] on breast density over a 12-month period. Mammographic assessment found no significant change from baseline in breast tissue density following this intervention. These results lend further support to the notion that flaxseed does not appear to have a significant estrogenic effect in vivo.3

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BCCT does not recommend therapies or doses, but only provides information for patients and providers to consider as part of a complete treatment plan. Patients should discuss therapies with their physicians, as contraindications, interactions and side effects must be evaluated.

Dosage recommendations are available from these sources:

Human studies are limited but suggest that if anything, including one to four tablespoons of flaxseed per day might reduce breast cancer risk, especially in post-menopausal women.

AICR consultant Karen Collins, MS, RDN, CDN, FAND

A blog post from the American Institute for Cancer Research advises: "Human studies are limited but suggest that if anything, including one to four tablespoons of flaxseed per day might reduce breast cancer risk, especially in post-menopausal women.”7

Integrative Plans, Protocols and Medical Systems

For more information about plans and protocols, see our Integrative Plans and Protocols page.
  • Plans, protocols and programs
    • Abrams & Weil integrative medicine approaches for prostate cancer8
    • Alschuler & Gazella complementary approaches:9
      • Elimination and detoxification
      • Immune enhancement
      • Reversing insulin resistance
      • Breast cancer
      • Colorectal cancer
      • Prostate cancer
    • Block program:10
      • Core diet plan
      • Anti-inflammation
      • Blood circulation
    • Lemole, Mehta & McKee protocols:11
      • Whole foods diet
      • Peripheral neuropathy
      • Chemo brain
    • McKinney protocols12
      • Breast cancer
      • Cervical cancer
      • Ovarian cancer
      • Pancreatic cancer
      • Prostate cancer
      • Uterine cancer
      • Cancer risk reduction
    • Ornish Lifestyle Medicine

View All References

More Information

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