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Research Looks for Links Between Fish Oil, Lower Risk

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A study suggests that there may be a link between fish oil and a lower risk of breast cancer. Still, this study is preliminary and more research is needed to figure out if this link holds up under more rigorous testing.

Fish oil contains omega-3 fatty acids: eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). These compounds may have health benefits, including:

  • reducing inflammation
  • reducing cancer risk
  • improving heart health -- reducing certain fat levels in blood (cholesterol and triglycerides) and reducing plaque buildup in heart arteries (coronary artery disease)

It's important to know that the only fish oil benefit that's been proven by research is lowering blood triglyceride levels.

You can add fish oil to your diet by eating more fatty fish (salmon, mackerel, lake trout, sardines) or by taking fish oil supplement capsules.

More than 35,000 postmenopausal women have been participating in this large research study, called the Vitamins and Lifestyle study (VITAL). The VITAL study is looking to see if there are any health risks related to taking nutritional supplements. Unlike prescription medicines, supplements aren't regulated or analyzed by the U.S. Food and Drug Administration (FDA) for health benefits and risks. VITAL has been recording the health of the participating women and their use of nutritional supplements.

From 2000 to 2007, 880 women in the VITAL study were diagnosed with invasive breast cancer. The supplements these women took were compared to the supplements taken by the women in the study who weren't diagnosed with breast cancer.

Women who were taking fish oil were 32% less likely to be diagnosed with breast cancer compared to women who didn't take fish oil. Still, taking fish oil before the VITAL study started wasn't linked to lower breast cancer risk. This suggests that regularly taking fish oil may contribute to lower breast cancer risk; taking fish oil for a period of time and then stopping doesn't seem to lower breast cancer risk.

Some women take fish oil for better cardiovascular health. The VITAL study suggests that taking fish oil may increase breast cancer risk in women who have been diagnosed with coronary artery disease. Still, there were only a small number of women in the VITAL study who were diagnosed with coronary artery disease, so this area needs more research.

The VITAL study also looked for any link between breast cancer risk and other nutritional supplements.

Breast cancer risk didn't seem to be influenced by:

  • glucosamine
  • chondroitin
  • methylsulfonylmethane
  • grapeseed

(These supplements are used for possible anti-inflammatory benefits -- to help ease arthritis, for example.)

  • black cohosh
  • dong quai
  • soy
  • St. John's wort

(These supplements are used to ease menopause symptoms.)

  • acidophilus
  • coenzyme Q10
  • garlic
  • ginkgo biloba
  • ginseng
  • melatonin

(These supplements are taken for a variety of possible health benefits.)

While these results are promising, more research is needed to help doctors decide if fish oil supplements truly lower breast cancer risk.

It's also promising that none of the supplements in the VITAL study seemed to increase breast cancer risk. Still, all supplements may have potential health risks along with the benefits. If you're taking or thinking of taking one or more supplements, be sure to ask your doctor about any health risks as well as how a supplement might interact with any medicines you may be taking.

For more information on well-known supplements and suggestions for using them, visit the Dietary Supplements page in the Breastcancer.org Nutrition Section.

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