Omega-3 fatty acids, from fish like salmon and other sources, have for years been shown to help lower levels of heart disease and cardiac death.
New research suggests the fatty acids may possess an even more fundamental benefit: Heart patients with high omega-3 intake had relatively longer "telomeres," which are stretches of DNA whose length correlates with longevity.
Cardiologists from the University of California, San Francisco, and other hospitals measured telomere length over five years in 608 patients who had coronary-artery blockage and previous heart attacks. Researchers found that people with high levels of omega-3 fatty acids in their white blood cells experienced significantly less shortening of telomeres over five years, as compared with patients with lower omega-3 levels.
"What we're demonstrating is a potentially new link between omega-3 fatty acids and the aging process," said Ramin Farzaneh-Far, a clinical cardiologist and assistant medical professor at UCSF and San Francisco General Hospital who is the lead author of the research.
Published in this week's Journal of the American Medical Association, the study focused only on "marine" omega-3 found in fish, not the type found in vegetable sources like flaxseed, walnuts, canola oil or soybean oil.
The study didn't distinguish between meals of fatty fish and fish-oil supplements—leaving open the question of whether it's better for people to eat more fish, to eat plants such as flaxseed or just to take omega-3 supplements.
The American Heart Association, in a 2002 scientific statement in the journal Circulation, concluded that consuming omega-3 fatty acids in fish or supplements "significantly reduces subsequent cardiac and all-cause mortality." The fish most often cited are salmon, herring and sardines.
John LaPuma, a Santa Barbara, Calif., physician and nutrition expert, says, "The best data are in fish rather than supplements, but the data for supplements are better than they were five years ago."
There is "very little good evidence for the omega-3s from flax and walnuts," said Dr. LaPuma, author of "ChefMD's Big Book of Culinary Medicine." But these foods have other benefits, he said. For instance, "flax meal, by itself, is an important part of lowering LDL," or bad cholesterol, Dr. LaPuma said.
Researchers in the new study said they observed "baseline levels of marine omega-3 fatty acids were associated with decelerated telomere attrition over 5 years."
Additionally, Dr. Farzaneh-Far said, "in multiple studies, short telomere length [in white blood cells] has been shown to predict death and cardiovascular events and heart failure." He cautioned that "it's an open question as to whether telomere length is causal or just a marker" of cell death. But he referred to telomere shortening as "a key part of cellular aging."
"To definitively address the question of whether omega-3 fatty acids inhibit cellular aging, a double-blind, randomized, placebo-controlled trial would be necessary," the authors wrote. Dr. Farzaneh-Far suggested that such research should be done in healthy adults because the evidence already is powerful on behalf of advantages of these fatty acids in heart patients.
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