Researchers at the Fred Hutchinson Cancer Research Center, in Seattle, Washington tell us, “There have been no prospective studies of the association between the long-term use of these supplements (omega-3 fatty acids and others] and breast cancer risk….” until now.

This and other recent breakthroughs are summarized below.

First, the details.

  • 35,016 older women in the VITamins And Lifestyle (VITAL) Cohort study completed a 24-page questionnaire on their use of supplements.
  • The incidence of invasive breast cancer from 2000 to 2007 was obtained from the Surveillance, Epidemiology, and End Results (SEER) registry.

And, the results.

  • After 6 years of follow-up, 880 cases of breast cancer were identified.
  • Current use of fish oil was associated with a significant 32% reduced risk of breast cancer.
  • These results held for ductal but not lobular cancers.
    • More on breast ducts and lobes can be found here.
  • Supplements that are sometimes taken for menopausal symptoms (black cohosh, dong quai, soy, or St. John’s wort) were not associated with breast cancer risk.

The bottom line?

The authors concluded, “Fish oil may be inversely associated with breast cancer risk.”

OK. More fish oil lowers the risk of breast cancer.

But there’s more. The health effects of omega-3 fatty acids may be due to genetic differences in metabolism, according to The Center for Genetics, Nutrition and Health, in Washington, DC.

All this is good news. Now, this accumulated knowledge of fatty acids must be confirmed in future studies of patients in order to get a better idea of the patients most likely to benefit and the correct dosage.

In the related area of breast cancer therapy, a recently published review by researchers at the University of Aberdeen, Aberdeen, UK recommended that based what we know from epidemiological, laboratory, and animal studies, confirmation of the value of omega-3 as a complementary addition to standard breast cancer therapy should be a priority.

7/12/10 20:10 JR

Hi, I’m JR

John Russo, Jr., PharmD, is president of The MedCom Resource, Inc. Previously, he was senior vice president of medical communications at, a complementary and alternative medicine website.