Patient Question: Does taking fish oil or any type of omega 3 supplements effect a PSA level or cause prostate cancer?
Answer: Great question. I tweeted 7/11/13 about an interesting article. "Fish Oil May Raise Prostate Cancer Risk - Highest versus lowest intake of long-chain omega-3 fatty acids - http://ow.ly/2ygVJu . 2,198 men with risk for prostate cancer were followed in the SELECT (Selenium and Vitamin E Cancer Prevention Trial) Trial. 834 were diagnosed with prostate cancer. When looking at the consumption of total long-chain omega-3 fatty acids those men who were in the top 1/4 of consumers had a 43% increased risk of getting prostate cancer over those in the bottom 1/4. The risk for high grade disease was even higher, 71% greater than the low consumer. Jonny Bowden, in a Huffington Post blog noted that fish oil and other supplements weren't even given in this study.
As with so many studies there are innumerable variable that we don't take into consideration. Science/Medicine may change their minds next year. Look at how medicine has viewed estrogen in women. Over the last 20 years there have been several swings in it's favorability based on the variable looked at. This was not the first study to suggest this. An article in the American Journal of Epidemiology by Dr. Theodore Brasky et. al. in 2011 looked at similar data in the Prostate Cancer Prevention Trial (PCPT). This also suggested a trend but again they haven't looked at consumption of fish oil.
Is it definitive? No. Was it enough for me to think about what's in my medicine cabinet? Yes.