HEALTH NEWS

Study Title:

Fish Oil and Breast Cancer Risk

Study Abstract

Background: Use of nonvitamin, nonmineral “specialty” supplements has increased substantially over recent decades. Several supplements may have anti-inflammatory or anticancer properties. Additionally, supplements taken for symptoms of menopause have been associated with reduced risk of breast cancer in two case-control studies. However, there have been no prospective studies of the association between the long-term use of these supplements and breast cancer risk.

Methods: Participants were female members of the VITamins And Lifestyle (VITAL) Cohort. Postmenopausal women, ages 50 to 76 years, who were residents of western Washington State, completed a 24-page baseline questionnaire in 2000 to 2002 (n = 35,016). Participants were queried on their recency (current versus past), frequency (days/week), and duration (years) of specialty supplement use. Incident invasive breast cancers (n = 880) from 2000 to 2007 were obtained from the Surveillance, Epidemiology, and End Results registry. Multivariable-adjusted hazards ratios (HR) and 95% confidence intervals (95% CI) were estimated by Cox proportional hazards models.

Results: Current use of fish oil was associated with reduced risk of breast cancer (HR, 0.68; 95% CI, 0.50-0.92). Ten-year average use was suggestive of reduced risk (P trend = 0.09). These results held for ductal but not lobular cancers. The remaining specialty supplements were not associated with breast cancer risk: Specifically, use of supplements sometimes taken for menopausal symptoms (black cohosh, dong quai, soy, or St. John's wort) was not associated with risk.

Conclusions: Fish oil may be inversely associated with breast cancer risk.

From press release:

Fish oil may help prevent breast cancer

Eating oily fish or taking fish oil supplements often may help reduce risk of developing breast cancer, according to a study published in the July 2010 issue of Cancer Epidemiology, Biomarkers & Prevention.

The study led by Brasky T.M. and colleagues from Fred Hutchinson Cancer Research Center in Seattle, Washington found current consumption of fish oil was correlated with a 32 percent reduced risk of breast cancer.

The researchers surveyed 35,000 women ages 50 to 76 in the Vitamins and Lifestyle Cohort on their dietary habits between 2000 and 2002. A total of 880 incidents of invasive breast cancer were identified from 2000 through 2007 in a database called the Surveillance, Epidemiology and End Results Registry.

The researchers found a ten-year average use of fish oil was associated with reduced risk of breast cancer. But the reduction was found only in the risk of ductal, not lobular breast cancer.

There was no association observed between use of black cohosh, dong quai, soy, or St. John's wort and the risk of breast cancer.

Fish oil, which is high in omega-3 fatty acids, has already been found protective against a number of cancers. Likewise, eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA), two omega-fatty acids found in fish oil have already been found protective against cancer.

Breast cancer is diagnosed in more than 175,000 women and kills about 50,000 each year in the United States, according to the National Cancer Institute. An estimated 12.5 percent of American women are expected to develop breast cancer sooner or later in their life time.

Nutrition experts believe that breast cancer in many cases is preventable. Diet and lifestyle are important in affecting the risk of this disease.

Study Information

Theodore M. Brasky, Johanna W. Lampe, John D. Potter, Ruth E. Patterson, and Emily White.
Specialty Supplements and Breast Cancer Risk in the VITamins And Lifestyle (VITAL) Cohort
Cancer Epidemiology, Biomarkers & Prevention.
2010 July
Fred Hutchinson Cancer Research Center in Seattle.