A study published earlier this week linking fish oil to prostate cancer has triggered a minor frenzy in the news media. In recent years, fish oil has been the proverbial “golden boy” of the supplement world, winning bout after bout and racking up benefits related to conditions from depression to heavyweights like cardiovascular disease. No surprise then that the moment a contender threatens the crown, the media is all over the opportunity to smear this truly valuable dietary component.
The study examined associations between blood omega-3 fatty acid levels and risk of prostate cancer in men. Men with higher blood levels of omega-3’s had a 71% higher risk of aggressive prostate cancer than men with lower blood levels. Study authors conclude that findings suggest that these blood fats are likely involved in prostate tumor development.
I know of no other single study for which the drawn conclusions have been more wrongly stretched, strengthened and extrapolated than this one. Media outlets twisted the result to mean that supplementing with fish oil and even eating fish could cause prostate cancer!
There are two pieces to the problem here.
One, the study has serious flaws that drastically weaken the value of its result for drawing actionable conclusions. It tested blood levels of omega-3, NOT fish oil consumption. It was a retrospective case-control design, which can merely draw associations, NEVER cause and effect. The data was taken from another large-scale study not originally intended to look at omega-3’s. Authors did not control for major confounders known to influence prostate cancer risk such as body weight! Read an in depth critique in this reprint of comments by Dr. Robert Rountree, Chief Medical Officer of Thorne Research Inc.
Two, the media, and lay consumers of that media – two of my friends emailed me Tuesday to ask if they should stop taking fish oil – are jumping to extremes based on the results of a SINGLE study. Science takes far longer than that. Many more studies need to be done, far more robust than the current, before a decision can be made.
In the end it’s about being a smart consumer of health information. It’s about doing your homework and realizing that when it comes to scientific research, your local news station may NOT be doing theirs.