Study confirms link between omega-3 fatty acids and increased prostate cancer risk

A second large, prospective study by scientists at Fred Hutchinson Cancer Research Center has confirmed the link between high blood concentrations of omega-3 fatty acids and an increased risk of prostate cancer.

Published July 11 in the online edition of the Journal of the National Cancer Institute, the latest findings indicate that high concentrations of EPA, DPA and DHA – the three anti-inflammatory and metabolically related derived from and fish-oil supplements – are associated with a 71 percent increased risk of high-grade prostate cancer. The study also found a 44 percent increase in the risk of low-grade prostate cancer and an overall 43 percent increase in risk for all prostate cancers.

The increase in risk for high-grade prostate cancer is important because those tumors are more likely to be fatal.

The findings confirm a 2011 study published by the same Fred Hutch scientific team that reported a similar link between high blood concentrations of DHA and a more than doubling of the risk for developing high-grade prostate cancer. The latest study also confirms results from a large European study.

"The consistency of these findings suggests that these fatty acids are involved in prostate tumorigenesis and recommendations to increase long-chain omega-3 fatty acid intake, in particular through supplementation, should consider its potential risks," the authors wrote.

"We've shown once again that use of nutritional supplements may be harmful," said Alan Kristal, Dr.P.H., the paper's senior author and member of the Fred Hutch Public Health Sciences Division. Kristal also noted a recent analysis published in the Journal of the American Medical Association that questioned the benefit of omega-3 supplementation for cardiovascular diseases. The analysis, which combined the data from 20 studies, found no reduction in all-cause mortality, heart attacks or strokes.

"What's important is that we have been able to replicate our findings from 2011 and we have confirmed that marine omega-3 fatty acids play a role in prostate cancer occurrence," said corresponding author Theodore Brasky, Ph.D., a research assistant professor at The Ohio State University Comprehensive Cancer Center who was a postdoctoral trainee at Fred Hutch when the research was conducted. "It's important to note, however, that these results do not address the question of whether omega-3's play a detrimental role in prostate cancer prognosis," he said.

Kristal said the findings in both Fred Hutch studies were surprising because omega-3 fatty acids are believed to have a host of positive health effects based on their anti-inflammatory properties. Inflammation plays a role in the development and growth of many cancers.

It is unclear from this study why high levels of omega-3 fatty acids would increase prostate cancer risk, according to the authors, however the replication of this finding in two large studies indicates the need for further research into possible mechanisms. One potentially harmful effect of omega-3 fatty acids is their conversion into compounds that can cause damage to cells and DNA, and their role in immunosuppression. Whether these effects impact is not known.

The difference in blood concentrations of omega-3 fatty acids between the lowest and highest risk groups was about 2.5 percentage points (3.2 percent vs. 5.7 percent), which is somewhat larger than the effect of eating salmon twice a week, Kristal said.

The current study analyzed data and specimens collected from men who participated in the Selenium and Vitamin E Cancer Prevention Trial (SELECT), a large randomized, placebo-controlled trial to test whether selenium and vitamin E, either alone or combined, reduced . That study showed no benefit from selenium intake and an increase in prostate cancers in men who took vitamin E.

The group included in the this analysis consisted of 834 men who had been diagnosed with incident, primary prostate cancers (156 were high-grade cancer) along with a comparison group of 1,393 men selected randomly from the 35,500 participants in SELECT.

Explore further

High percentage of omega-3s in the blood may boost risk of aggressive prostate cancer

More information: "Plasma Phospholipid Fatty Acids and Prostate Cancer Risk in the Selenium and Vitamin E Cancer Prevention Trial." Journal of the National Cancer Institute, 2013.
Citation: Study confirms link between omega-3 fatty acids and increased prostate cancer risk (2013, July 10) retrieved 24 June 2019 from
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Jul 10, 2013
Stop that fish oil supplementation?

Jul 10, 2013
Here is the link to the abstract (and paid subscription paper)

Jul 10, 2013
Stop that fish oil supplementation?
maybe just add more soy and tomatoes ;)

"Soy and tomato combo may be effective in preventing prostate cancer"

...and vegetable fats:
"Men with prostate cancer should eat healthy vegetable fats"

Jul 10, 2013
Just to show that nothing beats eating a natural, minimally processed foodstuff. There are hundreds of other chemicals in natural foods that modern science yet to have a clue of working out how they ALL work together. Making simplified assumptions based on limited researches, that we need THIS to fix THAT without causing THOSE is just plain arrogance , since the knowledge is still incomplete. Those suckers subscribed to the hypes will just fatten the stocks of the Pharmacoms, paying to be guinea pigs.

Jul 10, 2013
My logic has always been , humans have to be able to catch a fish to survive? I wish more of these articles would explain , for the benefit of those who may not know , not all omega-3 fatty acids come from fish. The fatty acids found in fish are produced from the plant fatty acid alpha-linolenic , at ratios compatible with health , not massive doses as supplied by eating fish.
"Association between interaction and ratio of ω-3 and ω-6 polyunsaturated fatty acid and the metabolic syndrome in adults."
"Fish oils contains two types of omega 3 fatty acids, namely eicosapentanoic acid (EPA) and docosahexanoic acid (DHA)."
"This is in contrast to plant sources of omega 3 oils that contain alpha linolenic acid (ALA)."

Jul 11, 2013
As the incidence of Prostatic Cancer in elderly men is very high (but usually not clinically important) , raising it from 60% found at autopsies to the '60% plus 71% of 60%' yields the possibility of nearly 100% incidence which then really might become clinically important iF the added cases are more-aggressive.
Usually, prostatic cancers are quite slow-growing and most men expire before the disease has much clinical consequence.
Perhaps some epidemiologist here can help us understand better ..

Jul 14, 2013
Remember the math problem with yellow, green, and dark blue paint, and you had to calculate how to mix them to get dark green? That was Three Simultaneous Unknowns (or whatever it was called). Sure wasn't easy to solve.

Here's a problem: soon we will know the ten thousand most usual molecules in normal healthy food. Each has a nonlinear function of pros and cons for the amount eaten.

But you only have your local grocery store selection to play with. How do you optimize health and long life span? How do you balance the effects of what you ate on vacation? What to do when they simultaneously run out of spinach and carrots?

Now, there's a multivariate optimization problem for your IPad app, with 10,000 variables. And it's probably too heavy for the phone, so you have to pay to use the Cloud. And that means the friendly gentlemen will know even this in Langley, VA.


Sarcasm aside, a healthy diet is quickly becoming rocket science.

Jul 14, 2013
I will continue taking fish oil supplements, because I think the benefits to the brain and cardiovascular system outweigh the risks of prostate cancer.
However, I will take PSA tests until this theory is debunked.

Jul 14, 2013
I will continue taking fish oil supplements, because I think the benefits to the brain and cardiovascular system outweigh the risks of prostate cancer.
However, I will take PSA tests until this theory is debunked.

Jul 15, 2013
We are the Great Experimental Generation, starting with pharmacy and illegal drugs in the 60s and culminating in GM foods and genetic engineering. What works and how does it work? What are the side effects and long-term effects?

The only way to find these things out is to try them out on a large number of people for a large portion of their lives.

MKULTRA was a very small part of a much larger Experiment.

And soon enough a significant number of us will have realtime monitoring via implant transponders, which will make comprehensive data collection much easier. What we ingest and how it affects our chemistry will be know in unprecedented detail.

As soon as this becomes possible, insurance companies will make it mandatory.

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