Don’t Fear Your Fish Oil

The media went wild this summer with a study published in the Journal of the National Cancer Institute. The study linked elevated plasma omega-3 fatty acid levels (found in fish and fish oil supplements) to a heightened risk of prostate cancer.


"Hold the salmon: Omega-3 fatty acids linked to higher risk of cancer," read a CNN headline. "Does Fish Oil Increase One's Risk of Getting Prostate Cancer?" wrote Forbes. But the Huffington Post called the story for what it was, "Media Madness: Fish Oil Supplements Cause Prostate Cancer!"


Robert Rountree, MD, Chief Medical Officer of Thorne Research, Inc., spoke at the Raby Institute on the heels of the study's publication, and warned people to use caution when reading about the potential link.


"Considering the extensive body of literature that supports the anti-inflammatory effects of omega-3 fatty acids, there is no credible biological mechanism, nor is one suggested in the article, that would explain why these essential fatty acids might increase tumorigenesis," he said.


Jonny Bowden, PhD, CNS, echoes that sentiment in the Huffington Post. "The first thing you need to know is that no fish oil supplements-or any other kind of supplements, for that matter-were given in this study. None."


Rountree cited additional red flags, including:


• Researchers pulled data from a previously conducted trial, not originally intended to examine the relationship between omega-3 fatty acid levels and prostate cancer.


• Results conflict with other studies that suggest that omega-3 fatty acids protect against prostate cancer-studies designed to analyze that very outcome.


• One particular physiologic marker in a group of individuals with a given condition (i.e. an elevated omega-3 level in men with prostate cancer) does not prove causation, especially when diet or behavior can influence that marker.


• Researchers did not assess participants' dietary intake of fatty fish or omega-3 supplements. Conclusions are based on the results of a single blood test, which is subject to significant day-to-day variability. Other tests, such as the omega-3 index which measures both EPA and DHA within red blood cells, is a much more accurate indicator of long-term omega-3 intake and tissue status.


• Other risk factors might have influenced the purported outcomes in the study:


1. 53 percent were smokers.


2. 64 percent regularly consumed alcohol.


3. 30 percent had at least one first-degree relative with prostate cancer.


4. 80 percent were overweight or obese.


Writes Bowden: "The men with the higher levels of DHA weren't necessarily eating more fish, and we pretty much know that the majority weren't taking supplements (because the researchers said as much). Though DHA levels in the blood go up when you consume lots of omega-3s, they can also go up for other reasons, one of them being a low-fat diet."


So as you read about this study in the coming weeks, remember this: Correlation does not equal causation.


"Given the inconsistent data attributable to omega-3 fatty acids and prostate cancer, and acknowledging the broad range of health benefits that are almost universally accorded to omega-3 fatty acid consumption, it would be premature to stop eating fish or to discontinue taking omega-3 nutritional supplements on the basis of this study," Rountree said.


"Dr. Raby is very knowledgeable about all different kinds of treatments and is open to new ideas and natural remedies.  She is compassionate, understanding, honest and real."
- Raby Institute patient