by Craig Weatherby
Folks often ask us how much omega-3 fat they should be consuming.
This question flows from people's awareness of mounting evidence that omega-3s help prevent cardiovascular disease and protect heart patients.
Their 500 mg/day recommendation aligns with and bolsters the omega-3 intake advice from three official bodies: see our “Current guidelines for omega-3 intake” sidebar.
Study authors make recommendations for daily omega-3 intakeThe authors of a new study extensively reviewed data from a broad range of studies in almost 40,000 patients, and suggest daily targets for omega-3 consumption (Lavie JC et al 2009).
The paper appears in the August 11, 2009, issue of the Journal of the American College of Cardiology, and has made headlines worldwide.
“This isn't just hype; we now have tremendous and compelling evidence from very large studies, some dating back 20 and 30 years, that demonstrate the protective benefits of omega-3 fish oil in multiple aspects of preventive cardiology,” said lead author Carl Lavie, M.D., in a press release from the American College of Cardiology.
Dr. Lavie went on to say, “The strongest evidence of a cardio-protective effect of omega-3s appears in patients with established cardiovascular disease and following a heart attack with up to a 30 percent reduction in CV-related death.” (AAC 2009)
Dr. Lavie says that fish oil can also decrease the risk of atherosclerosis, arrhythmias, heart attack, sudden cardiac death and even health failure.
He adds that although there is a smaller benefit in reducing heart failure death—a nine percent death-rate reduction in a recent, major, randomized controlled trial—this is still very impressive given patients' grave prognosis.
“If we translate this finding, it means that we only need to treat 56 patients for four years to prevent one death,” he said. “And we are talking about a very safe and relatively inexpensive therapy” (AAC 2009).
Current guidelines for omega-3 intake
When asked how many omega-3s to take, we've pointed to guidance by three official bodies:
The American Heart Association recommends 1,000 mg per day for heart patients, and says that healthy people should eat fatty fish twice a week: omega-3-rich species like salmon, sardines, tuna, sablefish, and mackerel.
The International Society for the Study of Fatty Acids and Lipids (ISSFAL) recommends taking 660 mg of omega-3s per day, regardless of gender.
The US Institute of Medicine (IOM), which sets the recommended daily allowances (RDAs) for vitamins and minerals, recommends taking 260-400 mg of omega-3s per day (the higher amount for men, though there is no evidence that women need less).
To these we'll now add the 500 mg/day minimum recommended by the authors of the new heart-health evidence review.
Pick the right omega-3s… fish, not flax
Most evidence for their cardio-protective effects relates to the long-chain omega-3s known as DHA and EPA, which abound only in fish and fish oil.
The short-chain plant source omega-3 known as ALA--small amounts of which occur in leafy greens, with more found in walnuts and flaxseed--delivers lesser heart benefits. And those benefits occur mostly as a result of ALA being converted into EPA by the body, at a very inefficient rate of about 10 percent.
According to Dr. Lavie, EPA and DHA work by getting into the membranes of cells and, in doing so, may help to improve the heart's electrical activity, vascular tone, plaque stabilization and blood pressure, among other benefits. Studies show that the reduction in adverse cardiovascular events is inversely related to the tissue level EPA and, even more so, DHA.
Based on these findings, and because the body does not produce its own essential fatty acids, the authors recommend that healthy individuals should consume 500 mg daily of omega-3 fish oil containing EPA and DHA, and people with known heart disease or heart failure aim for at least 1,000 mg daily.
Ideally, people should split their omega-3 intake roughly equally between these two fatty acids (i.e., 250 mg or 500 mg each) because they bring different, overlapping cardiovascular benefits.
(The 500 mg recommendation for healthy people is double the 250 mg level recently recommended by a panel of the European Food Safety Authority. Prominent omega-3 researchers, including pioneering fatty acid scientist and informal Vital Choice advisor William E. Lands, Ph.D., have signed a petition urging the panel to reconsider.)
“There are clear health and heart benefits associated with increasing one's intake of foods that are rich in omega-3s, including oily fish like salmon, sardines, trout, herring, and oysters”, said Dr. Lavie. “Patients should talk with their doctors about whether a fish oil supplement is needed to get the right amount and, in turn, benefit from the associated cardiovascular protection” (AAC 2009).
Remaining therapeutic questions need answers
Dr. Lavie and his team came across only a few negative studies, including a recent one that showed no benefit in post-heart-attack patients, but it has raised the possibility that omega-3 fatty acids may not provide as much additional protective benefits in low-risk patients already receiving extensive and rigorous post-heart-attack therapies.
“It was a one-year study that enrolled fewer than 4,000 patients and the majority were using aspirin, Clopidogrel, statins, beta-blockers and ACE-inhibitors—the best of modern medicine,” he said. “It may be that their risk was so low to start, that a larger study with longer follow-up would be required to better assess the true efficacy of omega-3 in such relatively low-risk patients” (AAC 2009).
Dr. Lavie and his co-authors say further studies are needed to investigate and determine optimal dosages, as well as the relative ratio of DHA and EPA that provides maximum heart protection in those at risk of cardiovascular disease, and in the treatment of atherosclerosis, arrhythmias, and heart attacks.
Research shows that cultures with diets rich in fish oil (East Asian, Inuit, and Native Alaskan populations) had a lower prevalence of cardiovascular disease and mortality, including a reduced prevalence of atherosclerosis and heart disease, compared to European and United States populations where consumption of fish is lower.
Sadly, adoption of Western dietary practices by Asian and Native American cultures may be diluting the cardio-protective benefits enjoyed by these populations, by reducing intake of fish oils and overwhelming their benefits with junk food diets high in sugar, starch, and omega-6, saturated, and trans fats.
- Lavie JC et al. Omega-3 Polyunsaturated Fatty Acids and Cardiovascular Diseases. J Am Coll Cardiol, 2009; 54:585-594, doi:10.1016/j.jacc.2009.02.084
- American College of Cardiology (AAC). Study reveals mounting evidence of fish oil's heart health benefits: Researchers set forth recommendations for daily intake. August 3, 2009. Accessed at http://www.eurekalert.org/pub_releases/2009-08/acoc-srm080309.php