There are several different classifications of breast cancer. Recent research adds strong support to the use of fish oil in reducing the most common classification, known as invasive ductal carcinoma.
A study conducted by researchers at the Fred Hutchinson Cancer Research Center in Seattle, Washington, included 35,016 postmenopausal women between the ages of 50 and 76. Participants were members of the VITamins And Lifestyle (VITAL) study group. Subjects completed a 24-page baseline questionnaire that asked about recent (current versus past) supplement use. Frequency and duration of supplementation were also recorded. The women were asked specifically about the use of supplements other than basic vitamins and minerals.
After six years of follow-up, researchers found that regular use of fish oil supplements was associated with a 32 percent reduction in breast cancer risk. The reduced risk was limited to the most common form of breast cancer (the aforementioned invasive ductal carcinoma), which represents nearly 80% of diagnosed breast cancer cases. The highest level of benefit was also determined to be in women who were current users of fish oil.
Fish oil is a rich source of EPA (eicosapentoaenoic acid) and DHA (docosahexaenoic acid), two omega-3 fatty acids that have been studied extensively for prevention and treatment of various health conditions, including heart disease, arthritis and inflammatory conditions, macular degeneration, and depression. The results from this study give strong support to the possibility that regular fish oil consumption may also be associated with a reduced risk of the most common form of breast cancer.
Brasky TM, Lampe JW, Potter JD, Patterson RE, White E. Specialty Supplements and Breast Cancer Risk in the VITamins And Lifestyle (VITAL) Cohort. 2010. Cancer Epidemiol Biomarkers Prev 19(7):1696-708.