The nutrition world just got dealt a curve ball this week when the results of a 2011 study just released warned us against the dangers of high levels of Omega 3 – for men. We have heard for the longest time how Omega 3 fatty acids from fatty fish will help protect us from heart disease, reduce triglycerides, act as a natural blood thinner and generally help to keep the cardiovascular system in good condition. And all of the above is true. Fish oil does do that – we know it does. But now we know that it might do something else too. Unfortunately the study showed that high levels of omega 3 showed a significantly increased risk of developing prostate cancer (43%) and those that had the highest levels of EPA and DHĀ – which is the omega 3 from fatty fish – had a 71% of developing an aggressive form of prostate cancer. Scary stuff.
The data comes from a study known as SELECT. Originally it looked at the effect of selenium and vitamin E on prostate cancer. What was found that vitamin E increased risk of cancer, but selenium had no effect. This is not the first time that studies have shown dangerous effects of supplementing with vitamin E. There is another well known study where taking vitamin E in supplemental form increased the growth of lung cancer and that study had to be abandoned. What has also come out of the SELECT data now is the increased risk of prostate cancer with too much omega 3.
Like vitamin E supplementation, it’s also not the first time we have heard that omega 3 might cause a growth in prostate cancer. There have been other studies, which raise concerns about the effect of omega and prostate risk. But like all things to do with nutritional science – on the other hand, a research study specifically designed to elucidate the effects of Omega 3 on prostate cancer concluded that there was no significant relationship. This study was a meta-analysis that looked at eight other studies to try to figure some this stuff out. The fact is – we just don’t know.
So now we have to ask ourselves – does this pose a problem for men who use omega 3 as protection from heart disease? It’s not uncommon for people to take up to 2 grams, or even higher on a daily basis to protect their cardiovascular health. Men in the study who were developed prostate cancer had blood levels of omega 3 that would be comparable to eating a little over 2 meals of fatty fish per week. That would be about 4-6 grams of omega 3 if you had a 6 ounce portion of wild Alaskan Salmon at each meal. But the amount of omega 3 can vary widely depending on the type of fish and whether it is farm raised or wild caught.
What has to be remembered though is that the SELECT was not designed to test the effect of omega 3 and prostate cancer, so the information needs to be taken cautiously. It might well make a difference if the omega 3 in the SELECT study was the result of supplementation with fish oil tablets or eating fish. When nutrients are taken in isolation they seem to have a different effect on the body than if they obtained naturally from food. The interaction of other nutrients and phyto-chemicals in food all play into how a micronutrient reacts in the body.
It seems that the real message is to be wary of too much supplementation. If you are taking omega 3 for heart health under with the approval of your doctor it would be a good idea to talk to your doctor about your risks for prostate cancer and your heart risk before you make a decision. Don’t just quit taking it without letting your doctor know because if you do decide to quit taking it, there might be other things that have to happen to protect your cardiovascular system.
You might be wondering if its a better idea to get your omega 3 from flax seeds or chia seeds. Getting omega 3 from non animal sources will limit the amount of EPA and DHA because plant sources don’t contain it. Your body will make EPA and DHA with the use of niacin, pyridoxine, vitamin C, magnesium and zinc. Because of the need for a lot enzymatic work using these vitamins, the conversion isn’t efficient and you won’t get the same amount of EPA and DHA. The truth is, we don’t have enough information and to quote another recent study
“This discontinuity of scientific evidence from animal to human studies suggests that future studies should focus on defining the optimal dosage range and the efficacy of n-3 PUFA compared to standard treatments using standardised study designs. Further studies on ALA would seem justified.”
Here is what you can do in regard to your diet to help protect your heart. If triglycerides are a problem for you – it might be worth adopting a lower carb diet to help keep your triglycerides lower. Lots of sugar and starch and alcohol raise triglycerides, so it’s a good idea not to consume excessive amounts of those. If you need to get cholesterol down then eating lots of soluble fiber will help do that for you. You need about 30 grams fiber a day in total, with half of it being soluble. Eat a moderate amount of healthy fat in the form of olives, avocados and coconut oil. And eat plenty of beans and lentils, red, yellow, and green vegetables along with a few walnuts per day and plenty of vitamin C rich foods. And eat moderate amounts of wild caught fatty fish – limit it to twice per week.
National Cancer Institute Selenium and Vitamin E Cancer Prevention Trial (SELECT)
Am J Respir Crit Care Med. 2008 Mar 1;177(5):524-30. Epub 2007 Nov 7.
Long-term use of supplemental multivitamins, vitamin C, vitamin E, and folate does not reduce the risk of lung cancer. Slatore CG, Littman AJ, Au DH, Satia JA, White E.
Can Urol Assoc J. 2013 May;7(5-6):E333-43. doi: 10.5489/cuaj.1056.
The relevance of serum levels of long chain omega-3 polyunsaturated fatty acids and prostate cancer risk: A meta-analysis Chua ME, Sio MC, Sorongon MC, Morales ML Jr.