High doses of omega-3 fatty acids may protect against further damage in heart attack patients, a preliminary study suggests.
The research included 374 heart attack survivors who received standard treatment and took either a 4-gram prescription-only dose of omega-3 fatty acids each day or a placebo.
The researchers said that people probably couldn't get that level of omega-3 fatty acids from diet alone.
To illustrate how large a dose that is, the researchers noted that 4 grams of omega-3 fatty acids is the equivalent of eating 8 ounces of salmon.
Using MRIs, the patients' hearts were scanned two weeks, four weeks and six months after their heart attack.
Compared to those taking the placebo, patients taking the omega-3 capsules had lower levels of inflammation and were 39 percent less likely to show deterioration of heart function.
There was also less thickening or scarring of the areas of the heart that were not directly damaged during the heart attack. This thickening, also known as fibrosis, often develops when the surviving heart muscle works harder to compensate for the damaged tissue, according to the researchers.
Patients with a 5 percent rise in the amount of omega-3 fatty acids in their blood seemed most likely to benefit from the supplements.
The study is to be presented March 16 at the annual meeting of the American College of Cardiology (ACC) in San Diego. Research presented at meetings should be considered preliminary until published in a peer-reviewed journal.
"Giving a high dose of fish oil [omega-3 fatty acids] soon after a heart attack appears to improve cardiac structure and heart functioning above and beyond the standard of care," senior study author said Dr. Raymond Kwong in an ACC news release.
He is director of cardiac magnetic resonance imaging at Brigham and Women's Hospital in Boston.
"Because this is a unique group of patients with remarkably high adherence to [guideline-directed] treatments for acute [heart attack] already, we feel fairly confident that the benefits from the supplement are additive. The implications of this study could be fairly large," Kwong said.
Previous research has shown that omega-3 fatty acids may lower the risk of heart rhythm problems and death from heart attack.
"Fish oil [omega-3 fatty acids] may have anti-inflammatory effects and also promote better cardiac healing," Kwong said. "This is important because other anti-inflammatory agents, including steroids and NSAIDs, have failed to make a difference after [heart attack]."
About 735,000 Americans suffer a heart attack each year, according to the U.S. Centers for Disease Control and Prevention.