A new analysis could lead to heated debate among heart dictors over whether omega-3 polyunsaturated fatty acids deserves its own recommended daily intake levels.
Fish oil -- a centuries-old pharmacy shelf fixture -- has recently been the subject of much research to determine its heart-protecting properties. Now, some cardiologists say it is time for omega-3 polyunsaturated fatty acids to join others nutrients for which a daily recommended intake has been established.
Dr. Carl Lavie, medical director of Cardiac Rehabilitation and Prevention at the Ochsner Heart and Vascular Institute in New Orleans, is one such cardiologist. He says that healthy people should consume at least 500 mg per day of eicosapentaenoic acid (EPA) plus docosahexaenoic acid (DHA) in order to meet their daily needs for the nutrient.
Lavie and his colleagues made the recommendations in a paper released Monday in the Journal of the American College of Cardiology.
Those with known cardiovascular disease, the researchers added, should consume 800 to 1,000 mg per day of the nutrient.
Such recommendations, if widely established, could solidify omega-3's place in the pantheon of nutrients that diet experts recommend.
But other cardiologists were more measured in their assessment and at least one -- the oft-quoted contrarian Dr. Steven Nissen, director of cardiovascular medicine at the Cleveland Clinic -- said Lavie's conclusions are premature.
"I don't find the evidence for widespread usage of omega-3 particularly compelling," Nissen said.
Others, including Dr. Robert Bonow, past president of the American Heart Association and co-director of the Bluhm Cardiovascular Institute at Northwestern University in Chicago, attempted to temper the enthusiasm by pointing out that while advising patients to increase consumption of fish oil may be "good advice," it should be tempered by adding the caveat that the data are "strongest in those with established heart disease ... with the principal benefit being a reduction in serious rhythm problems.
"The other benefits do appear to be real, but there is less evidence -- and in some cases no evidence -- that these lead to better patient outcomes," Bonow added.
Lavie based his recommendation on a review of findings from four studies that, in total, looked at about 40,000 study participants -- ranging from healthy individuals to those who had experienced a heart attack or other cardiac problem.
The studies revealed a number of potential advantages to taking in omega-3 fatty acids. One piece of research showed that in men who had recently experienced a heart attack, those who took omega-3-rich fish oil were 29 percent more likely to be alive after two years than their non-fish-oil-eating counterparts.
Even Lavie noted, however, that not all studies have been kind to omega-3s. In his study, he writes that one previous trial showed that patients who have experienced a form of heart-related chest pain known as angina who are treated with fish oil "seem to have a higher risk of [sudden cardiac death] than untreated control subjects." At least one other study has shown the benefits of omega-3 for those who have suffered a heart attack to be questionable.
This has not stopped some heart doctors from using omega-3 supplements in their patients, however. Dr. Melvyn Rubenfire, director of preventive cardiology at the University of Michigan in Ann Arbor, says he is currently using EPA + DHA supplements in patients with coronary artery disease because "available evidence supports it."
But Rubenfire added that he would like to see a "trial in the modern era in patients on other evidence-based treatments such as aspirin, [blood pressure] control, statin and non smoking" to confirm an omega-3 benefit on top of standard care.
And then there is the question of whether people who take commercially available supplements will be getting enough of the nutrient to make a difference. Rubenfire warned that the lack of regulation in the supplement industry means "that 1,000 mg of fish oil caplets may contain as little as 300 mg of EPA+DHA."
The American Heart Association (AHA) appears to already be on board with omega-3 guidelines. The organization's current recommendation is that people with confirmed coronary heart disease should consume 1,000 mg daily of combined DHA + EPA. For healthy adults, the AHA recommends consuming 500 mg per day, which works out to consuming at least two servings of fatty fish a week.
But while it does promote heart healthy diets for all, the AHA remains wary about mercury contamination in fish and cautions that fish with the highest potential for contamination -- namely shark, swordfish, king mackerel or tilefish -- should be avoided.