Surprising findings on omega-3s, trans fats, and prostate cancer risk don’t warrant a change in diet

By Suzanne Rose, Editor, Annual Report on Prostate Diseases

Over the past four years, I’ve read numerous studies and spoken with several experts on the connection between nutrition and prostate cancer. Although their recommendations for men concerned about prostate health haven’t always been consistent, most agreed on two things: eat more healthy fat, particularly the omega-3 fats found in fatty fish like salmon, and eat less unhealthy fat, namely trans and saturated fats. So I did a double take when I came across a study in the American Journal of Epidemiology that came to the opposite conclusion.

Chronic inflammation may play a role in the development and progression of prostate cancer. Omega-3 fats tend to be calm inflammation, while trans fats tend promote it. So researchers analyzed data and blood samples from 3,461 men ages 55 to 84 in the nationwide Prostate Cancer Prevention Trial to examine the relationship between the levels of these and other fats and prostate cancer risk.

Men with the highest levels of DHA, a type of omega-3, were 2.5 times more likely to have developed aggressive, high-grade prostate cancer over a seven-year period compared with men who had the lowest levels of DHA—the exact opposite of what the researchers had hypothesized. Another surprising result was that men with the highest blood levels of trans fats, often found in processed foods, were 50% less likely to have developed aggressive, high-grade prostate cancer compared with those who had the lowest levels.

“Our findings are disconcerting,” the researchers wrote,” as they suggest that omega-3 fatty acids, considered beneficial for coronary artery disease prevention, may increase high-grade prostate cancer risk, whereas trans fatty acids, considered harmful, may reduce high-grade prostate cancer risk.”

Should these results prompt men to scale back on fish and eat more processed food? I put that question to Stacy Kennedy, senior clinical nutritionist at Dana-Farber Cancer Institute, and Dr. David Rosenthal, director of Harvard University Health Service and medical director of the Leonard P. Zakim Center for Integrative Therapies at Dana-Farber. Both gave me an emphatic “no.” One key reason: the risk of dying from heart disease is much higher than the risk of dying from prostate cancer.

Eating moderate amounts of wild salmon, walnuts, pumpkin seeds, and other foods rich in omega-3s is a healthy strategy, Kennedy told me. The best “medicine” for men who are worried about their risk of prostate cancer is to maintain a healthy weight, eat plenty of fruits and vegetables, exercise regularly, and control stress. The good news is that taking these steps will promote heart health, too.

Posted May 5, 2011


  1. Frank

    I’m not sure I buy this study at all either. After increasing my Salmon intake my PSA levels didn’t increase, to the contrary, it dropped. I also added more fiber to my diet, Oatmeal and Bran.

  2. Michael

    What this study shows to me is that men who develop aggressive prostate cancer tend to modify their diets to increase Omega 3 and reduce transfats, thereby giving the appearance, after developing the disease, that less O3 & more transfats in blood is found in those who do not have aggressive prostate cancer, and conversely, more O3 and less transfat in blood is found in those who do. This is a good example of how a study can be interpreted incorrectly.

  3. SKY

    if pumpkin seeds,cayenne pepper capsules,or pomegranates dont get rid of the prostated

    inflammation,nothing will.

  4. Paul F Davis

    Thanks for this great article and research.

  5. Ahmed

    When you ask your doctor or any doctor(specialist)about prostate cancer, cholesterol, cardio-vascular related problems, blood pressure, diabets1,2 the answer will be, you have to avoid saturated fats, trans fats, etc. and gives you advise to chenge your diet(eat vegetables fruits Omega3 rich foods), do excercise, approach to proper weight,etc. it seems that all these illeness have a common trigger, then what is taht common trigger? i think this need deeper researchs on the matter.

  6. Terri

    I too would be interested in knowing the incidence of prostate cancer in Japan and surrounding areas that consume large amounts of Omega 3.

    I am a nutritionist and have learned that men that consume large amounts of omega 6 increase their risk of prostate cancer?

    My husband has had prostitis for 6+ months. He has been on antibiotics for all this time and still has symptoms. We have taken him off omega 3 for now. What is causing this inflammation and why can no one treat it. My Osteopath suggested he could release some of the scar tissue from all the inflammation, any thoughts or recommendations would be greatly appreciated!!!

  7. T. Lawalsh

    So… no Omega 3 supplements?

  8. Uriahh

    Once again the epidemiologists have stirred up some cloudy soup! The contrairian results of this study are so outstanding that they have to be approached with great caution. The statistical analyses shows confidence limits around the mean values big enoug to drive a truck through.

    So before anyone dumps the accepted wisdom regarding omega 3’s and their ilk, let’s see if anyone replicates the results. Keep the grill hot and the fresh fish broiling!

  9. David Holzman

    I second the request for absolute numbers.

  10. Greg Williams

    It would be interesting to know if countries with really high fish consumption, like Japan and Iceland, have high prostate cancer rates.

  11. Phyllis Heard

    just basing research on diet and food without looking at pesticide residues in fat and lipid production and the resulting endocrine disruption and neurotoxicity is falling short.Prostrate cancer may be caused by stress? There is no greater cause of oxidative stress in my view than the continued use of excess pesticides with associated penetrants or surfucants designed to permeate the plant waxes possibly causing chaos in the human fat and lipid chain.

  12. David L

    I wish the absolute risk increase had been given. This report doesn’t give sufficient information to make an informed judgment. What is the value that is increased by a factor of 2.5? If it is very low then it’s not a big deal. If it is not so low then there is reason for concern.

  13. Ted Harazda

    What would be a moderate amount of salmon? I consume about a pound of wild salmon a week.

    Are there still any cultures still known for a high salmon or other high omega 3 fish diet…say in the Pacific coast areas from British Columbia to Alaska? If so, it would be interesting to know of the prostate cancer incidence rate in those populations.

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