Research links higher omega-3 levels with reduced rates of breast fibrocysts and related cancer risks
by Craig Weatherby
At some point in their lives, about six in 10 women will experience the changes in the breast tissue called fibrocystic breast disease or FBD.
Calling this normally benign condition a disease is misleading, since, in most cases, the changes are safe and non-cancerous.
But there are variations in FBD, and some raise cancer risk substantially.
The most common types, called non-proliferative fibrocystic conditions, do not increase your risk for breast cancer.
However, about one-third of women biopsied for suspicious breast conditions have a proliferative fibrocystic condition… the type associated with a significantly greater risk of breast cancer.
The highest-risk group is the four percent of women with fibrocystic tissue containing so-called “atypical cells”.
For all these groups, the risks are higher if the fibrocystic condition occurred when the woman was only in her 30’s or 40’s. A strong family history of breast cancer can also increase the risks for later developing the disease.
Fibrocystic breast disease usually subsides with menopause, when ovary function changes, and FBD also may vary during the menstrual cycle.
It’s most common in women between the ages of 30 and 50, less so in women who take birth control pills, and rare in women who have passed through menopause.
Omega-3 EPA linked to reduced rates of breast fibrocysts and cancer
An omega-3 fatty acid called EPA is essential to human metabolism and immunity, and it’s also one of the two key omega-3s in fish oil.
A recent study in women with breast cancer found that, compared with the women with the lowest blood levels of EPA, the women who had the highest blood levels of EPA had less than half the risk of having fibrocystic breasts, and were about half as likely to have breast cancer.
Similar study finds like benefits from soy isoflavones
Two years ago, the US-Chinese team uncovered similar links between higher blood levels of soy isoflavones and rates of FBD and cancer.
Compared to women with low levels of an isoflavone called genistein, those with high blood levels were 26 percent less likely to have breast cancer and 40 percent less likely to have FBD.
Researchers at Oregon Health and Science University noticed that although benign breast changes are more common than breast cancer, we have little evidence regarding risk factors for benign breast conditions.
As they wrote, “Omega-3 fatty acids have anti-inflammatory and anti-proliferative actions and may be important in reducing the risk of benign conditions.”
So the Oregonians teamed with Chinese researchers to search for any statistically significant links between blood levels of various fatty acids, and the risks of proliferative and non-proliferative fibrocystic disease.
The conducted a case-control study among 1,611 women in Shanghai, China… including 581 diagnosed with some form of FBD and 1,030 healthy controls.
Their objective was to evaluate the role of omega-3 and other fatty acids in the development of fibrocystic breast conditions and benign non-proliferative fibrocystic breast conditions (NPFCs), and to evaluate the progression of fibrocystic changes in breast cancer.
The found that the 25 percent of the women with the highest blood levels of omega-3 EPA were 67 percent less likely to have any form of FBD.
And among women with (somewhat riskier) proliferative fibrocystic breast conditions, the 25 percent with the highest blood levels of omega-3 EPA were 49 percent less likely to also have breast cancer.
Interestingly, women with high levels of a saturated fat called palmitic acid also had reduced rates of FBD and cancer, though it was not as large an effect as the one found with EPA.
And the women with the highest levels of omega-6 GLA were the most likely to have either FBD or cancer. This fits with a fast-growing body of evidence linking excess intake of omega-6 fatty acids to inflammation—a suspected factor in fibrocyst formation—and cancer.
As the Oregon-Shanghai team wrote, “Our results support protective effects of omega-3 fatty acid intake… against benign fibrocystic breast changes and the progression of proliferative changes to breast cancer.”
Earlier Harvard study found no link; Weight of evidence favors omega-3s
Sixteen years ago, a Harvard team published a similar case-control study, in which they failed to detect these associations between fatty acid levels and rates of breast cancer or FBD (London SJ et al. 1993).
Time will tell which team’s results prove to hold more predictive power.
In the meantime, lab, animal, and epidemiological evidence indicates that omega-3s from fish discourage cancer growth.
For more on this, see “Breast Cancer and Omega-3s: More Encouraging Evidence” and search our archives for “breast”.
And the available evidence shows that, when they’re eaten in excess, omega-6 fats fuel tumors. These dominate most vegetable oils—except olive, macadamia, and special hi-oleic sunflower oils—and abound in standard, grain-fed meats, and in prepared/packaged foods
Given these findings, it seems pretty smart to favor fish and minimize intake of corn, soy, cottonseed, and standard sunflower and safflower oils… as well as grain-fed beef, pork, chicken, and farmed fish.
- Lampe JW, Nishino Y, Ray RM, Wu C, Li W, Lin MG, Gao DL, Hu Y, Shannon J, Stalsberg H, Porter PL, Frankenfeld CL, Wähälä K, Thomas DB. Plasma isoflavones and fibrocystic breast conditions and breast cancer among women in Shanghai, China. Cancer Epidemiol Biomarkers Prev. 2007 Dec;16(12):2579-86.
- London SJ, Sacks FM, Stampfer MJ, Henderson IC, Maclure M, Tomita A, Wood WC, Remine S, Robert NJ, Dmochowski JR, et al. Fatty acid composition of the subcutaneous adipose tissue and risk of proliferative benign breast disease and breast cancer. J Natl Cancer Inst. 1993 May 19;85(10):785-93.
- Shannon J, King IB, Lampe JW, Gao DL, Ray RM, Lin MG, Stalsberg H, Thomas DB. Erythrocyte fatty acids and risk of proliferative and nonproliferative fibrocystic disease in women in Shanghai, China. Am J Clin Nutr. 2009 Jan;89(1):265-76. Epub 2008 Dec 3.