Regular consumption of fish oil supplements, which contain high levels of the omega-3 fatty acids, EPA and DHA, was linked with a 32 percent reduced risk of breast cancer concluded the observational study conducted at the Fred Hutchinson Cancer Research Center, Seattle, Washington.
The reduction in risk seemed to be limited to invasive ductal breast cancer, the most common type of the disease.
Omega-3 fatty acids
Lead researcher Emily White, works with the center’s public health sciences division, said: “It may be that the amount of omega-3 fatty acids in fish oil supplements are higher than most people would typically get from their diet.” But she highlighted the need for more research: “Without confirming studies specifically addressing this we should not draw any conclusions about a causal relationship.”
Researchers asked 35,016 postmenopausal women in Washington State, aged between 50 and 76, who did not have a history of breast cancer to complete a 24-page questionnaire about their use of non-vitamin, non-mineral specialty supplements.
After six years, 880 cases of breast cancer were identified using the Surveillance, Epidemiology and End Results registry.
The use of other supplements, sometimes taken by women to treat menopause symptoms, such as black cohosh, dong quai, soy, or St. John's wort, were not associated with the reduced risk of breast cancer.
White’s study is the first to link the use of fish oil supplements with a decreased risk of this type of cancer. Previous studies have proved inconsistent.
One theory is that fish oil reduces inflammation which contributes to the development of cancer.
Fish oil has also been linked to a protective effect on cardiovascular disease.
Meanwhile, researchers at Harvard University are seeking patients for the randomized Vitamin D and Omega-3 Trial. The research programme, known as VITAL, will assess the impact of fish oil supplements and vitamin D on cancer, heart disease and stroke.
Breast cancer occurs in both men and women but male breast cancer is rare. The National Cancer Institute estimated that there will be 207,090 new cases of female breast cancer this year and 1,970 new cases in males.
It predicts that the disease will cause 39,840 female deaths and 390 male deaths.
Source: Cancer Epidemiology, Biomarkers & Prevention, American Association for Cancer Research (AACR) Canc Epidemiol Biomark Prevent. July 19, 2010.
Title: Specialty Supplements and Breast Cancer Risk in the Vitamins And Lifestyle (VITAL) Cohort
Authors: E White, T Brasky, J Lampe, J Potter, and R Patterson