Omega-3 Fish Oil: Bad for the Prostate?

Consuming large amounts of omega-3 fatty acids may not be right for everyone: Researchers have observed a link between the intake of omega-3 —found in fish-oil supplements and fresh tuna, salmon, and trout–and an increased risk of prostate cancer.

Scientists found a strong association between high consumption of omega-3 fatty acids and a 43 percent increased risk of prostate cancer, according to a new study in the journal of the National Cancer Institute. Furthermore, omega-3 fatty acids are also connected to a 71 percent increased risk of aggressive prostate cancer.

This isn’t a definitive warning for men to steer clear of fish oil, but the findings are significant enough to warrant discussion. The anti-inflammatory properties of fish oil and omega-3s have been touted to aid in everything from depression to asthma to autoimmune diseases. Even the American Heart Association recommends fish oil or fatty fish as often as twice per week, based on evidence that it decreases triglyceride levels and the risk of abnormal heartbeats.

What’s the Connection?

Though the new study supports findings from earlier research that links prostate cancer risk and omega-3s, we need more research to uncover exactly why the two are connected. It’s possible that higher levels of omega-3s can actually damage a man’s DNA in a way that encourages prostate cancer tumor growth.

Dietary supplements come in and out of favor with the latest research, magazine articles and healthcare trends, which can make it difficult to decipher what helps and what hurts. For many, a balanced diet may be the best course of action.

Start by talking with your doctor, who can provide a comprehensive perspective on the latest research, your individual health, and your risk levels related to various diseases. If you’re at risk for heart disease, maybe fish oil can help. If you have a family history of prostate cancer, perhaps you should avoid it. For most, a balanced diet provides what the body needs and supplements may be unnecessary.

7 Responses to “Omega-3 Fish Oil: Bad for the Prostate?”

  1. dan murray

    I take 1000mg of fish oil a day is that to much in regards to this new study about the relationship between fish oil and prostate cancer?

    • David Samadi, MD

      If you have any family history of prostate cancer or an elevated PSA, I recommend you stop taking fish oil until we have further studies. Maintaining a balanced diet of two or three portions of fish a week should be enough Omega-3 fatty acid. Blood tests will reveal how much EPA and DHA you are receiving.

  2. Nancy Mohrmann

    I have been hearing doctors and biochemists on radio the past week mentioning that this is not really a good study; it isn’t double blind, etc. Also they said that a large percentage of the people studies with prostate cancer were obese (something like 80%), 40-something percent have a strong family history and 50 something percent were heavy smokers. I don’t have the exact numbers in front of me but these are pretty close.

  3. David Samadi, MD

    It is true that this study was not designed directly for this purpose, but the correlation and association that they observed was quite strong. This is the second study that correlates the relationship between fish oil and prostate cancer. I agree that this is not a cause-and-effect study and does not prove the risk, but it is strong enough to recommend and get this information to public.

    No question that we need better designed studies. But for now if you have a family history of prostate cancer or elevated PSAs, you need to avoid taking fish oil. Try two to three portion of salmon a week instead and that should help.

  4. M Dulko

    Asian men have the lowest incidence of prostate and are one of the largest consumers of fish ;please explain.

  5. Smith

    This doesn’t make sense to me doctor. The study didn’t discriminate where the fish oil came from but you are recommending fatty fish 3 times a week over a daily 1000mg supplement? Salmon will easily have 2000mg per serving of omega 3 and at 3x a week that’s 6000mg. So 6000mg from fatty fish is ok in a week, but 7000mg from a supplement is dangerous?

  6. David Samadi, MD

    Thank you for your comment. While this could be a confusing topic for everyone, the best way to clarify this for the time being is to limit the amount of fish oil one takes.

    Remember, all the studies on supplements so far are not really done scientifically. Since my work is all dedicated to prostate cancer, I am trying to make everyone aware that it COULD harm them. So limiting the amount of it and sticking to two portions of salmon would be enough to protect the heart while not causing any issues with your prostate.

    No one has the crystal ball right now, but the similar phenomenon happened with Vitamin E, so common sense and moderation are the key.


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