But what does the science say? A systematic review and meta-analysis published in the Journal of the American Medical Association,highlighted in my video Is Fish Oil Just Snake Oil? looked at all the best “randomized clinical trials evaluating the effects of omega-3’s on lifespan, cardiac death, sudden death, heart attack, and stroke.” The studies told the subjects to either eat more oily fish or to take fish oil capsules. What did the study find? Overall, the researchers found no protective benefit for all-cause mortality, heart disease mortality, sudden cardiac death, heart attack, or stroke.
What about for those who already had a heart attack and are trying to prevent another? Still no benefit. Where did we even get this idea that omega 3’s were good for the heart? If we look at some of the older studies, the results seemed promising. For example, there was the famous DART trial back in the 80s involving 2,000 men. Those advised to eat fatty fish had a 29% reduction in mortality. Pretty impressive—no wonder it got a lot of attention. But people seemed to have forgotten the sequel, the DART-2 trial. The same group of researchers, and an even bigger study (3,000 men). In DART-2 “those advised to eat oily fish and particularly those supplied with fish oil capsules had a higher risk of cardiac death.”
Put all the studies together, and there’s no justification for the use of omega 3s as a structured intervention in everyday clinical practice or for guidelines supporting more dietary omega-3’s. So what should doctors say when their patients follow the American Heart Association advice to ask them about fish oil supplements? Given this and other negative meta-analyses, “our job as doctors should be to stop highly marketed fish oil supplementation in all of our patients.”
I’ve previously discussed fish oil supplements in the context of risks versus purported cardiovascular benefits:
- Dietary Supplement Snake Oil
- Fish Oil in Troubled Waters
- DDT in Fish Oil Supplements
- Is Cod Liver Oil Good For You?
- Are krill oil supplements better than fish oil capsules?
But if the benefits aren’t there, then all one is left with are concerns over the industrial pollutants that concentrate in the fish fat (even in distilled fish oil, see Is Distilled Fish Oil Toxin-Free?).
- Fish Intake Associated With Brain Shrinkage
- Mercury vs. Omega-3s for Brain Development
- How Long to Detox From Fish Before Pregnancy?
–Michael Greger, M.D.
PS: If you haven’t yet, you can subscribe to my free videos here and watch my live year-in-review presentations Uprooting the Leading Causes of Death, More Than an Apple a Day ,and From Table to Able.
Image Credit: Jo Christian Oterhals / Flickr