Fish oil associated with lower breast cancer risk

Postmenopausal women who take fish oil supplements may have a one-third lower risk for developing breast cancer than those who don't use supplements, according to the results of a recent observational, case-control study.

The study involved 35,000 postmenopausal women between the ages of 50 and 76 years participating in the VITamins And Lifestyle (VITAL) Cohort. The women, who resided in western Washington state, completed a 24-page questionnaire that included questions about current and past use of fish oil and other supplements. They were followed for an average of 6 years, during which time 880 women were diagnosed with the breast cancer.

The study found that current, regular use of fish oil supplements reduced the risk for breast cancer (hazard ratio, 0.68; 95% confidence interval [CI], 0.50-0.92). The reduced risk remained even after adjusting for a number of known and suspected risk factors for breast cancer, including older age, obesity, heavy drinking, and sedentary lifestyle. The results held for ductal cancers but not for lobular disease. Ten-year average use of fish oil was also suggestive of reduced risk (P trend=.09).

Brasky TM, Lampe JW, Potter JD, Patterson RE, White E. Specialty supplements and breast cancer risk in the VITamins And Lifestyle (VITAL) cohort. Cancer Epidemiol Biomarkers Prev. 2010;19(7):1696-1708.