Omega-3 fatty acids and Prostate Cancer

Posted on 25 July 2013 in by Dr. John Dawson
Dr. John Dawson

Earlier this month a study was published claiming a link between omega-3 fatty acids in the blood and prostate cancer. It seems as though when any article is published linking anything to cancer people stand up and notice, and the article usually gathers momentum in the press and social media.

The article itself is full of methods, results, and conclusions that come along with various 'randomized trials', significant 'p values', and various 'causal and correlation statements'. Taking the time to sift through all the technical terms , interpret all the scientific data, and find experts who agree and disagree with the findings would certainly take too much time before the initial statement has passed by its fifteen minutes of fame in the high paced media of today. However, it is important that an article with claims of such magnitude be given more than just fifteen minutes.

For any proper analysis to be done an original copy of the article needs to be obtained. Furthermore, it is necessary for 'the entire article to be reviewed'. There are websites that allow people to access an 'abstract' of an article which gives a brief summary of what the article wanted to test, how it did the test, and what was found; however, this is not enough. Using abstracts from journal articles is a quick way of gathering information to prove a point and say that the information was gained from scientifically proven sources.

Quoting respected researchers who have reviewed the article in its entirety such as Dr. James Chestnut B.Ed., M.Sc., D.C., C.C.W.P and Dr. William Harris PhD:

'The select trial was actually a trial designed to study the effects of selenium and Vitamin E supplementation on Prostate Cancer risk. The study was never designed or set up to prospectively study either the intake of fish oil or to measure the effect of fish oil consumption on the incidence of prostate cancer.'
'...the study did not test the question of whether giving fish oil supplements or eating more oily fish increased prostate cancer risk, it simply measured omega-3 levels in the plasma (which can also be affected by genetics and metabolism) and correlated them with incident prostate cancer up to 9 years later...correlation does not imply causation.'
'Remember also that we have no data about how much omega-3 fatty acids these subjects were consuming or what their source of omega-3 fatty acids were (contaminated fish with cancer causing mercury and PCBs or contaminant-free fish oil).'

The unfortunate thing that has happened here is that something was noticed in this particular study that was not being tested or controlled using the scientific method—it was simply realized after the fact. Even more unfortunate is how media and readers quickly pick up on headlines and journal abstracts that contain buzz phrases like 'cancer linked with' or 'research shows' without taking the time to read more than just the headline.

If 500 people in the Isle of Man were surveyed; and, of those 500 people 12 had been in road traffic accidents; and, of those 12 accidents 3 had been driving motorcycles—does that mean that people driving motorcycles in the Isle of Man are more likely to be involved in a road traffic accident? With this simple statistic is it fair to say that 25% of all road traffic accidents in the Isle of Man involve motorcycles? No.

I think Dr. Harris concluded his commentary best with the following statement:

'Study authors and the media alike must discipline themselves to report the findings themselves and to resist the temptation to wildly extrapolate in order to grab headlines. They need to provide a balanced context to show the nuances in science that might be lost on general audiences, and to ensure that their conclusions do not overreach their data, particularly when doing so can put patients at risk.'

Please find links below for the complete versions of the articles I have referenced. Furthermore, feel free to contact the clinic to clarify any questions you have on omega-3 fatty acid supplementation. If you would like to come into the clinic to arrange a twenty minute consultation—at no charge—on this topic please use the 'contact us' page.