Are the purported benefits of fish oil supplementation for the prevention and treatment of heart disease just a “fish tale“? Thanks to recommendations from organizations such as the American Heart Association that individuals at high risk for heart disease ask their physicians about fish oil supplementation, fish oil has grown into a multibillion dollar industry. We now consume over 100,000 tons of fish oil every year.
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
- Are krill oil supplements better than fish oil capsules?
These same contaminants are found in the fish themselves. This raises concern for children (Nerves of Mercury), and pregnant moms:
- 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.
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