Fish and Prostate Cancer Risk

Recent studies suggest that high intake of omega-3 fats increases your risk of prostate cancer. Should you stop taking fish oil? Nutrition Diva takes a closer look at the pros and cons of fish and fish oil for men.

Monica Reinagel, MS, LD/N, CNS,
July 31, 2013
Episode #245

Page 2 of 2

(continued from previous page)

What's the Link Between Omega-3s and Prostate Cancer? 

In any case, most of the men in this latest study weren't taking fish oil supplements. The higher omega-3 levels observed here appear to be mostly the result of higher fish consumption. Which brings us to the million dollar question: Does eating fish increase your risk of prostate cancer? And if so, how do you weigh the benefits to your heart and brain against the potential risk to your prostate?

First, let me point out this finding is a correlation, meaning that these two characteristics (high blood levels of omega-3s and prostate cancer) tend to occur together. This study does not prove that omega-3s cause prostate cancer. In fact, other researchers have found a correlation between higher omega-3 blood levels and reduced risk of prostate cancer. Still other studies suggest that the relationship or ratio of omega-3s to other types of fat may be a factor.

See also: Does the Omega Ratio Matter?


I realize this is not very helpful for guys who are simply trying to figure out whether they should or should not order the salmon tonight. Unfortunately, that's how science works.  Scientists get used to dealing with this sort of uncertainty. When it's your prostate on the line, it's not so easy to be blase about it. But it might help settle your nerves to put the risks in perspective.

Putting the Risks in Perspective

The study found that men with the highest intake of fish oil had a 71% increase in aggressive prostate cancer. That's a big number connected to a scary diagnosis.  But as I explained in a recent episode, expressing things in terms of  relative risk often makes things seem a lot scarier than they actually are. Let me restate the same findings in slightly different terms:  If you're over 50 and you rarely or never eat fish, your risk of developing aggressive prostate cancer is a little over 1%. If you eat two or more servings of fish a week, your risk is a little under 2%. Meanwhile, your risk of developing heart disease is approximately 50%.

My Advice On Fish, Fish Oil, and Life in General

So, what, if anything, should you do in response to this new research? Ideally, decisions about diet and supplementation should be made in consultation with your doctor and/or a qualified nutrition professional who knows the details of your specific medical history. For example, if you have a history of or risk factors for either heart disease or prostate cancer, that would certainly influence how you'd weigh the cardioprotective benefits of fish against potential prostate risk. 

But here are some general guidelines that I think apply across the board. (Most will be familiar to you from past Nutrition Diva episodes.)

1. As much as possible, get your nutrition from food instead of pills.  A healthy diet beats a handful of supplements every time.

2. More is not always better.  Even healthy foods and valuable nutrients can be harmful when consumed in excess quantities. Aim for balance, variety, and moderation.

3. Live the healthiest life you can enjoy living.  Although the choices we make certainly have an impact, there's no one diet or lifestyle that guarantees that you'll never face health challenges. A lot of it is due to factors beyond our control. So, do the best you can but make sure to enjoy the ride!

See also: Moderation in All Things



Brasky TM, Darke AK, Song X, et al.  Phospholipid Fatty Acids and Prostate Cancer Risk in the SELECT Trial. J Natl Cancer Inst. 2013 Jul 10. View abstract

Kris-Etherton PM, Harris WS, Appel LJ; American Heart Association. Nutrition Committee. Fish consumption, fish oil, omega-3 fatty acids, and cardiovascular disease. Circulation. 2002 Nov 19;106(21):2747-57. View article  Norrish AE, Skeaff CM, Arribas GL, Sharpe SJ, Jackson RT. Prostate cancer risk and consumption of fish oils: a dietary biomarker-based case-control study. Br J Cancer. 1999 Dec;81(7):1238-42. View article Williams CD, Whitley BM, et al. A high ratio of dietary n-6/n-3 polyunsaturated fatty acids is associated with increased risk of prostate cancer. Nutr Res. 2011 Jan;31(1):1-8. View abstract.  

Fish dinner image courtesy of Shutterstock.


You May Also Like...