Flaxseed – Anti-cancer Properties in the Breast? An Interesting Question.

In a fascinating and well-done study, Swedish researchers found that in women undergoing breast reduction surgery, those who took Flaxseed (25 grams daily) had a significant increase in levels of IL-1Ra – an inhibitor of pro-cancerous inflammatory cytokines – in the breast tissue taken at surgery.

The effect of flaxseed was similar to that in women who before the surgery took Tamoxifen, an estrogen receptor modulator that lowers breast cancer risks and is used to treat estrogen-sensitive breast cancers.

Women who were exposed to estrogen before their surgery, on the other hand, had lowered IL-1 levels and an increase in pro-cancerous inflammatory cytokines on their breast biopsies.

Estradiol, Tamoxifen, and Flaxseed Alter IL-1β and IL-1Ra Levels in Normal Human Breast Tissue in Vivo.Annelie Abrahamsson, Vivian Morad, Niina M. Saarinen and Charlotta Dabrosin

Objective: The objective of this study was to elucidate whether estrogen, tamoxifen, and/or diet modification altered IL-1 levels in normal human breast tissue.

Design and Methods: Microdialysis was performed in healthy women under various hormone exposures, tamoxifen therapy, and diet modifications and in breast cancers of women before surgery. Breast tissue biopsies from reduction mammoplasties were cultured.

Results: We show a significant positive correlation between estradiol and in vivo levels of IL-1β in breast tissue and abdominal sc fat, whereas IL-1Ra exhibited a significant negative correlation with estradiol in breast tissue. Tamoxifen or a dietary addition of 25 g flaxseed per day resulted in significantly increased levels of IL-1Ra in the breast. These results were confirmed in ex vivoculture of breast biopsies. Immunohistochemistry of the biopsies did not reveal any changes in cellular content of the IL-1s, suggesting that mainly the secreted levels were affected. In breast cancer patients, intratumoral levels of IL-1β were significantly higher compared with normal adjacent breast tissue.

Conclusion: IL-1 may be under the control of estrogen in vivo and may be attenuated by antiestrogen therapy and diet modifications. The increased IL-1β in breast cancers of women strongly suggests IL-1 as a potential therapeutic target in breast cancer treatment and prevention

It’s a very interesting study, though certainly not enough data to make any kind of statement about flaxseed for cancer prevention. Swedish women undergoing reduction mammoplasty are certainly not representative of the population of women at large.
And before you go stocking up on flaxseed, read this on the potential risks as well as benefits of flaxseed and its oil.

All that said, I still find this a very interesting study with a biologically plausible result, and hope there’s more data coming from this group an others on this approach to cancer prevention and treatment.