Fish oil may reduce breast cancer risk
MedWire News: Researchers studying the impact of non-vitamin, non-mineral, specialty supplements on cancer risk have found that regular use of fish oil may reduce the risk for breast cancer.
Theodore Brasky (Fred Hutchinson Cancer Research Center, Seattle, Washington, USA) and colleagues asked 35,016 postmenopausal participants of the Vitamins and Lifestyle (VITAL) cohort study with no history of breast cancer, to complete a 24-page questionnaire about their use of specialty supplements.
After 6 years of follow-up, 880 cases of breast cancer were identified in the cohort using the Surveillance, Epidemiology and End Results registry.
The researchers found that regular use of fish oil supplements was associated with a 32% reduced risk for breast cancer. Further analysis revealed that the reduced risk was restricted to women with ductal but not lobular carcinoma.
Other specialty supplements reported by the women were not associated with breast cancer risk. These included black cohosh, dong quai, soy, and St John's wort, which are commonly taken to treat the symptoms of menopause.
This is the first prospective study to demonstrate a link between the use of fish oil supplements and a reduction in breast cancer risk, remarks the research team. Previous studies of dietary intake of fish or omega-3 fatty acids have been inconsistent.
However, "until these results are replicated, fish oil supplements should not be promoted for reduction of breast cancer risk," Brasky and co-authors caution.
They add that further studies should focus particularly on the timing of exposure and dose of fish oil, as well as on mechanisms of action that might explain differences by tumor stage or histologic type.
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By Laura Dean