Do Omega 3 Fats Increase Prostate Cancer Risk?

The short answer is No!!!  Omega 3 fats from fish and fish oil have been shown in numerous (hundreds) scientific studies to be associated with decreases in various chronic diseases, such as heart disease, diabetes, and cancer of various types.  Omega 3 fats like DHA and EPA (found in fish) are anti-inflammatory and we know that inflammation is a factor in many chronic diseases, such as cancer. A recent paper has been making the news that claims that higher levels of omega 3 fats in the blood are associated with higher rates of prostate cancer. http://www.ncbi.nlm.nih.gov/pubmed/23843441  This is being reported in the news as reason not to take fish oil supplements.  But this study does not prove that and the paper is very problematic.

First of all, this retrospective study was not conducted to test the effects of fish oil.  It was a study published several years ago that looked at the relationship between Vit E and selenium and prostate cancer.  Then they went back and looked for correlations between other nutritional factors and prostate cancer. They found that higher levels of omega 3 in the blood in this group were correlated with aggressive prostate cancer and that men with higher levels of omega 6 fats (which are pro-inflammatory) were the least likely to get aggressive prostate cancer, a result contrary to lots of other research.  The researchers do not know if any of the subjects were supplementing with fish oil or in fact, anything about their diets, so this result could have been a result of eating fish or walnuts or flaxseeds or maybe related to the cancer.  Should we stop eating fish and walnuts and flaxseeds and eat more corn oil?  If this study was accurate, then prostate cancer would be rampant in countries where fish consumption is high, such as Japan.  But the opposite is true.  And lots of research correlates the Mediterranean diet with longevity and reduced risk of various chronic diseases, including cancer, and fish consumption is a big part of this dietary approach.  This study by Brasky, et al, also found that smoking cigarettes resulted in a lower risk of prostate cancer than not smoking, so you have to question the results of this study.