Dietary Fats and Prostate Health

Omega-3s not good for prostate health

/ Author:  / Reviewed by: Joseph V. Madia, MD

(RxWiki News) You can't turn around without hearing praise for the health benefits of omega-3 fatty acids. Likewise, trans-fatty acids are considered one of the most unhealthful substances we can eat. Well, hold your horses - when it comes to prostate health, all that's wrong!

Found in fish oil, omega-3s are known to be good for the heart because they reduce inflammation. But new findings show omega-3s can be bad - very bad - for the prostate. Meanwhile, trans-fatty acids actually reduce the risk of aggressive prostate cancer.

Researchers from Fred Hutchinson Cancer Research Center found that men with the highest amounts of DHA, an inflammation-lowering omega-3 fatty acid, have a much higher (2 1/2 times) risk of developing aggressive, high-grade prostate cancer compared to men with the lowest DHA levels.

Conversely, those with the highest rates of trans-fatty acids in their blood had a 50 percent lower risk of this deadly form of prostate cancer.

"Omega-3s increase the risk of aggressive prostate cancer, while trans-fatty acids cut that risk."

"We were stunned to see these results and we spent a lot of time making sure the analyses were correct," said Theodore M. Brasky, Ph.D., a postdoctoral research fellow in the Hutchinson Center’s Cancer Prevention Program.

"Our findings turn what we know — or rather what we think we know — about diet, inflammation and the development of prostate cancer on its head and shine a light on the complexity of studying the association between nutrition and the risk of various chronic diseases."

Brasky and the researchers undertook the study because chronic inflammation is known to increase the risk of several cancers, and the omega-3 fatty acids found primarily in fish and fish oil supplements have anti-inflammatory effects.

In contrast, other fats, such as the omega-6 fats in vegetable oil and trans-fats found in fast foods, may promote inflammation.

"We wanted to test the hypothesis that the concentrations of these fats in blood would be associated with prostate cancer risk," Brasky said. "Specifically, we thought that omega-3 fatty acids would reduce and omega-6 and trans-fatty acids would increase prostate cancer risk."

So based on these findings, should men concerned about heart disease not take fish oil supplements or eat grilled salmon in the interest of reducing their risk of aggressive prostate cancer? Brasky and colleagues don’t think so.

"Overall, the beneficial effects of eating fish to prevent heart disease outweigh any harm related to prostate cancer risk," Brasky said. "What this study shows is the complexity of nutrition and its impact on disease risk, and that we should study such associations rigorously rather than make assumptions," Brasky said.

The Study

  • Study based on data from the Prostate Cancer Prevention Trial, a nationwide randomized clinical trial that tested the efficacy of the drug finasteride to prevent prostate cancer
  • While the trial involved nearly 19,000 men age 55 and older, data in this analysis came from a subset of 3,400 study participants, half of whom developed prostate cancer during the course of the study and half of whom did not
  • Prostate biopsy was used to confirm the presence or absence of prostate cancer in all study participants
  • Most participants got omega-3s from eating fish, not from supplements
Reviewed by: 
Review Date: 
April 27, 2011
Last Updated:
May 3, 2011