Many of you have emailed or called with concerns about the new study that claims that fish oil can increase risk of prostate cancer. After reading the original research, these are my thoughts as they pertain to my patients who are on fish oil or for anyone for that matter may be concerned about their supplementation.

The first point to note is that the length of the study and the sheer number of people involved was quite large. It was a randomized, placebo-controlled trial over 7 years with over 18,000 male patients over age 55. It is really important when analyzing research that you consider the length of the trial and the number of people involved. In the case of research, bigger and longer is better.

However, between January 1994 and May 1997, 18,882 men were randomized to receive Finasteride (5 mg/day) or placebo. Finasteride decreases DHT or dihydrotestosterone. DHT is a metabolite of testosterone and is considered "supercharged testosterone" as it is 2-3 times stronger than testosterone. When DHT is high it can cause male pattern baldness and prostatic inflammation. But 2 studies in 2012 showed that decreasing DHT too low with medications such as Finasteride and Dutasteride was been shown to increase risk of invasive prostate cancer. This risk was serious enough for the FDA to send out a warning on the medications themselves. See it here:

http://www.fda.gov/drugs/drugsafety/ucm258314.htm

So now the study looks very different. At least ½ of these men in the study (the other half placebo) were given a medication to reduce DHT. We don't know if DHT was ever measured again; in my clinical experience treating many men who have been put on these medications, it rarely is.

Where does the omega 3 come in to the picture? Non-fasting blood was collected approximately 3 months prior to randomization and annually thereafter until diagnosis or the end of the study. "Non-fasting" is a problem here. All lipids should be drawn fasting so that we can see what is going on in a system un-affected by foods that were ingested 8-10 hours prior. Additionally, we are missing key pieces of information: no dietary history was taken, no supplementation history was taken AND this study was NOT based on giving men a fish oil supplement for 7 years and measuring the outcome. It was simply based on what the non-fasting blood every 3 months told them. We have no idea what other medications these patients were on or what their history of hyperlipidemia is. Finally, there are certain metabolic conditions that raise serum lipids and we don't know what those were, who may have had those conditions or how they may or may not have been treated.

Correlation does not determine causation. This study was certainly interesting, but in my opinion, it speaks much, much more to the research in 2012 that showed that Finasteride and other alpha reductase inhibitors that reduce DHT can increase risk of a more invasive type of prostate cancer.

When doing research, it is important to control as many variables as you can so that you can really see a correlation between the things you are studying. I don't believe that this study controlled for enough of those variables, leaving many questions unanswered.

How does this relate to you, who may be on a lot of fish oil? First of all, too much of anything can be unhealthy. About 2400 mg of Omega 3's daily has been shown to decrease inflammation and reduce harmful serum cholesterol (triglycerides and LDL). This same amount has also been shown to reduce PSA and C-reactive protein that are both markers for inflammation. My proof? Many years of practice measuring blood levels of these markers in many men every few months on fish oil, coupled by prostate exams, ultrasounds and biopsy results.

It is very important that the fish oil you use is pure and tested by a 3rd party. The supplements I prescribe to all my patients fit these criteria. Additionally, fish oil should always be stored in the refrigerator. We know that when oils go rancid which they can very quickly from light and ambient temperatures, they become carcinogenic. It is difficult to taste the difference when this happens, especially if they are in capsule form.

It is also an important point here that getting fatty acids from whole foods is ideally the best way to obtain them. It is always better to eat cold-water fish 3 days a week than to take a ton of pills. It is better to eat an abundance of nuts and legumes and avocados and other foods that contain high quality healthy fats. If you eat a balanced diet and eat whole foods and reduce the amount of saturated fat you get from other animal foods, including red meat, dairy, eggs, chicken, turkey, etc. you will be much healthier for it.

And then finally, if you are on a DHT blocker like Finasteride, and many of you who are on testosterone therapy are, it is crucial that those levels are measured every 3 months so that we are certain that your DHT is not too low. If we keep it in a healthy range, your chances of invasive prostate cancer are, as far as we know now, not any different than someone else's.

So to sum it up, while this study was interesting, I feel that it wasn't clear by the end what exactly was causing the issue. It was a very muddy study and it was not made clear enough whether or not supplementation is dangerous. I am not concerned and am not recommending my patients go off of fish oil at this time.