The Real Facts on Prostate Cancer and Omega-3s

Omega-3s: one day they’re a gift from the health gods; the next they’re a known carcinogenic. Here’s a critical look at the latest study linking omega-3s to prostate cancer.

You might have heard about the new study on omega-3 fatty acids – you know, the type pretty much everyone has recommended since we were all kids. Even our parents and some of their parents took cod liver oil as children to boost their health. Of course, back then it didn’t taste like it does now, sometimes lightly flavored with lemon. But the newest research has been blowing up in the media, and for good reason.

Specifically, the research indicated that people with the highest amount of omega-3 fatty acids in their blood had a 44%, 71%, and 43% greater risk of low-grade, high-grade and total prostate cancer, respectively.

With such a long history of supplementation, it makes sense that people are talking. If omega-3s really do cause prostate cancer, the male readers of Breaking Muscle are probably all at risk. Most of us have supplemented with a mercury-free alternative to an otherwise healthy high-fish diet.

The first thing to consider with a study like this is that we need to examine the results carefully. If we look at the results of this particular study, we see they give us a possible relationship, but not a cause.

Let me give you an example of what I mean. It’s true that increased dietary consumption of omega-3 fatty acids means greater plasma (blood) concentrations, especially for EPA, one of the omega-3s. DHA, the other primary omega-3 fatty acid, increases plasma concentrations only up to a point of consumption. In the prostate cancer study, elevated levels of either indicate a cancer risk.

But imagine if prostate cancer, amongst other things, prevented the body from using these omega-3s. With even a modest consumption of foods rich in omega-3s, the plasma levels may appear as though they were much higher than normal if that were true, because the omega-3s would be absorbed but not used. In that example, the results could appear exactly as they do in this study without omega-3s contributing to prostate cancer at all. There would be a relationship with an undiscovered cause.

The next point to consider is what other benefits omega-3s do have. Even if the risk for prostate cancer is increased, it might be true that it is worth the risk for the other benefits. Numerous studies support this consideration. To give you an idea, one study showed the reduction of many risk factors for numerous diseases, and another study showed a reduced risk of mortality. In other words, when we don’t isolate a single possible association, we see plainly that omega-3s are healthy.

So ultimately, what we have here is a dubious association between omega-3 consumption and the risk of one disease. However, we shouldn’t forget that omega-3s protect us from death, plain and simple. They also have numerous other benefits for athletes, so this is one case where we shouldn’t hold our breath for more damning evidence. Omega-3s are here to stay as a healthy part of an athlete’s diet.


1. Theodore M. Brasky, et. al., “Plasma Phospholipid Fatty Acids and Prostate Cancer Risk in the SELECT Trial,” J Natl Cancer Inst (2013) doi: 10.1093/jnci/djt174

2. Arterburn LM, et. al., “Distribution, interconversion, and dose response of n-3 fatty acids in humans,” Am J Clin Nutr. 2006 Jun;83(6 Suppl)

3. Dariush Mozaffarian , et. al., “Plasma Phospholipid Long-Chain ω-3 Fatty Acids and Total and Cause-Specific Mortality in Older Adults: A Cohort Study,” Ann Intern Med. 2013;158(7)

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