Fish oil appears to have substantial cardiovascular benefits. Now a large observational study of 35,000 women over six years suggests that those who take fish oil supplements had a lower risk of breast cancer. Fish oil users were one-third less likely to be diagnosed with this disease. The investigators are quick to point out that this type of study cannot show cause and effect and the only way to really know if fish oil has anti-cancer potential is to conduct a randomized, double-blind, placebo-controlled trial. Just such a study is enrolling 20,000 people, both men and women, to determine whether fish oil or vitamins can recue the risk of stroke, heart disease or cancer. It will be many years, though, before the results are published.
[Cancer Epidemiology Biomarkers and Prevention, July, 2010]