Advice to eat oily fish, or take fish oil, to lower risk of heart disease, stroke, or mortality is no longer supported by the balance of available evidence.
Is Fish Oil Just Snake Oil?
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Below is an approximation of this video’s audio content. To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video.
Are purported benefits of fish oil supplementation for the prevention and treatment of heart disease “just a fish tale”? Thanks to recommendations like this, from the American Heart Association—that individuals at high risk for heart disease ask their physicians about fish oil supplementation—it’s grown into a multibillion dollar industry. We now consume over 100,000 tons of fish oil every year.
But. what does the latest science say? “A Systematic Review and Meta-analysis” published in the Journal of the American Medical Association looked at all the best randomized clinical trials evaluating the effects of omega-3s on lifespan, cardiac death, sudden death, heart attack, and stroke. Either advice to eat more oily fish, or to take fish oil capsules. What did they find? Overall, they found no protective benefit for overall mortality, heart disease mortality, sudden cardiac death, heart attack, or stroke.
What about for those who’ve already had a heart attack, though, and are trying to prevent another one? Still, no benefit. Where did we even get this idea that omega-3s were good for the heart? Well, if you look at some of the older studies, the results looked promising—for example, 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 about the sequel, the DART-2 trial. Same group of researchers, an even bigger study—3,000 men. And, 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-3s. So, what should doctors say when their patients follow the American Heart Association advice to ask them about fish oil supplements? Well, given the new meta-analysis “and other negative meta-analyses, our job [as doctors] should be to stop highly marketed fish oil supplementation in all of our patients.”
Please consider volunteering to help out on the site.
- A. W. Turunen, A. Jula, A. L. Suominen, S. Männistö, J. Marniemi, H. Kiviranta, P. Tiittanen, H. Karanko, L. Moilanen, M. S. Nieminen, Y. A. Kesäniemi, M. Kähönen, P. K. Verkasalo. Fish consumption, omega-3 fatty acids, and environmental contaminants in relation to low-grade inflammation and early atherosclerosis. Environ. Res. 2013 120(NA):43 - 54.
- E. J. H. Lewis. Omega-3 Fatty Acid Supplementation and Cardiovascular Disease Events. JAMA 2013 309(1):27 - 27.
- M. L. Burr. Secondary prevention of CHD in UK men: The Diet and Reinfarction Trial and its sequel. Proc Nutr Soc 2007 66(1):9 - 15.
- M. L. Burr, P. A. L. Ashfield-Watt, F. D. J. Dunstan, A. M. Fehily, P. Breay, T. Ashton, P. C. Zotos, N. A. A. Haboubi, P. C. Elwood. Lack of benefit of dietary advice to men with angina: Results of a controlled trial. European journal of clinical nutrition 2003 57(2):193 - 200.
- S. M. Kwak, S.-K. Myung, Y. J. Lee, H. G. Seo. Efficacy of omega-3 fatty acid supplements (eicosapentaenoic acid and docosahexaenoic acid) in the secondary prevention of cardiovascular disease: A meta-analysis of randomized, double-blind, placebo-controlled trials. Arch. Intern. Med. 2012 172(9):686 - 694.
- F. B. Hu, J. E. Manson. Omega-3 fatty acids and secondary prevention of cardiovascular disease-is it just a fish tale? Arch. Intern. Med. 2012 172(9):694 - 696.
- M. L. Burr, A. M. Fehily, J. F. Gilbert, S. Rogers, R. M. Holliday, P. M. Sweetnam, P. C. Elwood, N. M. Deadman. Effects of changes in fat, fish, and fibre intakes on death and myocardial reinfarction: Diet and reinfarction trial (DART). Lancet 1989 2(8666):757 - 761.
- P. M. Kris-Etherton, W. S. Harris, L. J. Appel. Fish consumption, fish oil, omega-3 fatty acids, and cardiovascular disease. Arterioscler. Thromb. Vasc. Biol. 2003 23(2):e20 - 30.
- E. C. Rizos, E. E. Ntzani, E. Bika, M. S. Kostapanos, M. S. Elisaf. Association between omega-3 fatty acid supplementation and risk of major cardiovascular disease events: A systematic review and meta-analysis. JAMA 2012 308(10):1024 - 1033.
- C. J. Shepherd, A. J. Jackson. Global fishmeal and fish-oil supply: Inputs, outputs and markets. J. Fish Biol. 2013 83(4):1046 - 1066.
- Smith DA. Review: omega-3 polyunsaturated fatty acid supplements do not reduce major cardiovascular events in adults. Ann Intern Med. 2012 Dec 18;157(12):JC6-5.
Images thanks to Aardvark Ethel and James Palinsad via flickr
Below is an approximation of this video’s audio content. To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video.
Are purported benefits of fish oil supplementation for the prevention and treatment of heart disease “just a fish tale”? Thanks to recommendations like this, from the American Heart Association—that individuals at high risk for heart disease ask their physicians about fish oil supplementation—it’s grown into a multibillion dollar industry. We now consume over 100,000 tons of fish oil every year.
But. what does the latest science say? “A Systematic Review and Meta-analysis” published in the Journal of the American Medical Association looked at all the best randomized clinical trials evaluating the effects of omega-3s on lifespan, cardiac death, sudden death, heart attack, and stroke. Either advice to eat more oily fish, or to take fish oil capsules. What did they find? Overall, they found no protective benefit for overall mortality, heart disease mortality, sudden cardiac death, heart attack, or stroke.
What about for those who’ve already had a heart attack, though, and are trying to prevent another one? Still, no benefit. Where did we even get this idea that omega-3s were good for the heart? Well, if you look at some of the older studies, the results looked promising—for example, 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 about the sequel, the DART-2 trial. Same group of researchers, an even bigger study—3,000 men. And, 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-3s. So, what should doctors say when their patients follow the American Heart Association advice to ask them about fish oil supplements? Well, given the new meta-analysis “and other negative meta-analyses, our job [as doctors] should be to stop highly marketed fish oil supplementation in all of our patients.”
Please consider volunteering to help out on the site.
- A. W. Turunen, A. Jula, A. L. Suominen, S. Männistö, J. Marniemi, H. Kiviranta, P. Tiittanen, H. Karanko, L. Moilanen, M. S. Nieminen, Y. A. Kesäniemi, M. Kähönen, P. K. Verkasalo. Fish consumption, omega-3 fatty acids, and environmental contaminants in relation to low-grade inflammation and early atherosclerosis. Environ. Res. 2013 120(NA):43 - 54.
- E. J. H. Lewis. Omega-3 Fatty Acid Supplementation and Cardiovascular Disease Events. JAMA 2013 309(1):27 - 27.
- M. L. Burr. Secondary prevention of CHD in UK men: The Diet and Reinfarction Trial and its sequel. Proc Nutr Soc 2007 66(1):9 - 15.
- M. L. Burr, P. A. L. Ashfield-Watt, F. D. J. Dunstan, A. M. Fehily, P. Breay, T. Ashton, P. C. Zotos, N. A. A. Haboubi, P. C. Elwood. Lack of benefit of dietary advice to men with angina: Results of a controlled trial. European journal of clinical nutrition 2003 57(2):193 - 200.
- S. M. Kwak, S.-K. Myung, Y. J. Lee, H. G. Seo. Efficacy of omega-3 fatty acid supplements (eicosapentaenoic acid and docosahexaenoic acid) in the secondary prevention of cardiovascular disease: A meta-analysis of randomized, double-blind, placebo-controlled trials. Arch. Intern. Med. 2012 172(9):686 - 694.
- F. B. Hu, J. E. Manson. Omega-3 fatty acids and secondary prevention of cardiovascular disease-is it just a fish tale? Arch. Intern. Med. 2012 172(9):694 - 696.
- M. L. Burr, A. M. Fehily, J. F. Gilbert, S. Rogers, R. M. Holliday, P. M. Sweetnam, P. C. Elwood, N. M. Deadman. Effects of changes in fat, fish, and fibre intakes on death and myocardial reinfarction: Diet and reinfarction trial (DART). Lancet 1989 2(8666):757 - 761.
- P. M. Kris-Etherton, W. S. Harris, L. J. Appel. Fish consumption, fish oil, omega-3 fatty acids, and cardiovascular disease. Arterioscler. Thromb. Vasc. Biol. 2003 23(2):e20 - 30.
- E. C. Rizos, E. E. Ntzani, E. Bika, M. S. Kostapanos, M. S. Elisaf. Association between omega-3 fatty acid supplementation and risk of major cardiovascular disease events: A systematic review and meta-analysis. JAMA 2012 308(10):1024 - 1033.
- C. J. Shepherd, A. J. Jackson. Global fishmeal and fish-oil supply: Inputs, outputs and markets. J. Fish Biol. 2013 83(4):1046 - 1066.
- Smith DA. Review: omega-3 polyunsaturated fatty acid supplements do not reduce major cardiovascular events in adults. Ann Intern Med. 2012 Dec 18;157(12):JC6-5.
Images thanks to Aardvark Ethel and James Palinsad via flickr
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Title
Is Fish Oil Just Snake Oil?
LicenseCreative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0)
Content URLDoctor's Note
I’ve previously discussed fish oil supplements in the context of risks vs. purported cardiovascular benefits:
- Dietary Supplement Snake Oil
- Fish Oil in Troubled Waters
- 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 fish fat.
These same contaminants are found in the fish themselves. This raises concern for adults, children (see 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?
Are Fish or Fish Oil Supplements Good for the Heart? Check out the video.
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