OMEGA 3 & 6 FATTY ACIDS-WHAT ARE THE RISKS FOR PROSTATE CANCER?
There has been a flurry of concerns in the media recently about the alleged risks of developing Prostate Cancer (PCa) from supplementation with Omega 3 & 6 fatty acids (Om3&6). Prof Shingai Mutambirwa The Head of Urology at MEDUNSA provides some perspective.
OMEGA 3 & 6 FATTY ACIDS – WHAT ARE THE RISKS FOR PROSTATE CANCER?
There has been a flurry of concerns in the media recently about the alleged risks of developing Prostate Cancer (PCa) from supplementation with Omega 3 & 6 fatty acids (Om36).
Om3&6 are necessary for normal cellular functioning, including in the prostate gland, but reports have been published that “supplementation” of Om3&6 can increase the risk of PCa “…..by up to 60%” . Surprisingly, this comes after data previously reporting on the possible benefits in preventing PCa from the same fatty acids. Unfortunately the data for benefits are not convincing in most well designed studies, but even more unfortunate is the media fanfare about increased risk from using OM3&6. To cut a long story short, the study quoted by the general press is at the very least flawed, and at worst, completely alarmist. The data on the so called “dangers” of Om3&6 are based on what we researchers call a retrospective (looking back on old data) analysis of a trial that was set up to assess the potential of using a mineral (selenium-S) and a vitamin (E) to prevent prostate cancer. This was based on the fact that a (small) quantity of these substances are necessary for normal prostate health and the idea was that more of them would be beneficial for prostate cancer prevention. This was called the “SELECT” trial and was well constructed as a prospective, randomized, controlled double blinded study (PRDBs) for assessing E and S (but not Om3&6!) which accrued its required patient numbers for statistical significance and the final results were released in 2008 with an updated re-analysis in 2011.
“SELECT” turned out to be what we call a “negative” trial as the primary end point of PCa prevention was not met. In fact, worringly, there was a trend towards an increase in PCa in the Vitamin E group and for type 2 diabetes in the Selenium arm, although these data were not satisfied statistically and therefore cannot be confirmed from this study.
This is where the authors of the “study” on Om3&6 causing PCa have erred. Firstly, as stated above without statistical significance from a PRDBs no scientist worth his salt will make a firm conclusion on the data presented (which is exactly why we cannot say that E or S should not be taken, as a “trend” is not sufficient to draw a conclusion).
Secondly, as the SELECT trial’s aim was not to prospectively assess the role of Om3&6 to prevent (or cause) PCa, the fact that the trial itself was a PRDBs makes it inadeaqaute to make any bold claims about Om3&6. In fact as with many trials, Om3&6 was just one of many “unrelated” tests done for control and monitoring purposes.
As stated above, what the authors of the “risks” of Om3&6 did was a retrospective analysis of the SELECT trial data, which as any statistician will tell you has numerous and often irreconcilable flaws including selection bias (“berry picking”), inability to exclude confounding variables (eg did any of the patient population have a “binge” of vitamins at any stage?) amongst many others.
Thirdly, the Om3&6 “risk” was based on the retrospective (again!) analysis of blood levels ONLY and therefore cannot and were not referenced as to the source or amount of intake of Om3&6.Therefore, to say the Om3&6 levels were due to “supplementation” cannot be proven, and is in fact an untrue statement. There are many other flaws which could be quoted but would require the reader to have an in depth knowledge of statistics and trial design.
Suffice it to say there is currently NO convincing evidence that Om3&6 cause PCa. Similairly, on the other hand there is NO convincing evidence that Om3&6 help in the prevention of PCa.
My advise for any man whether worried by the data or not is simply LESS IS MORE.
Less calories in your diet, less laziness (ie Exercise!) both of which are PROVEN to decrease abdominal fat, diabetes and hypertension whilst lowering the bad blood fats (triglycerides,LDLs) and raising the good blood fats (HDLs) which = LESS Cardiovascular disease/Metabolic Syndrome which is PROVEN to decrease PCa risk.
LESS stress about unsubstantiated claims of benefits and risks of products are also good recommendations I might add!
By Prof. Shingai Mutambirwa Head of Urology MEDUNSA
