The health benefits of long-chain omega-3 fatty acids — docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) – are well known.
Recently, a large randomized controlled t
rial examined whether supplementing with 4 grams of omega-3 would help repair some of the damage caused by a heart attack. Below is a detailed summary of its findings.
This study examined the benefits of high-dose omega-3 supplementation on heart recovery after a heart attack.
This randomized controlled trial investigated the effects of omega-3 fatty acids on changes in heart function and structure during the first 6 months after a heart attack (acute myocardial infarction).
A total of 358 participants were randomly assigned to one of two groups 14 to 28 days after they had a heart attack:
- Omega-3: The participants received high-dose omega-3 supplements from fish oil (4 grams per day for 6 months). The supplement contained ethyl esters of EPA (465 mg) and DHA (375 mg).
- Placebo: The control capsules contained corn oil, providing 600 mg of omega-6 linoleic acid.
During the study, all of the participants were also receiving standard medical therapy to treat heart disease.
At the start and end of the study, the researchers measured heart structure and function using cardiac magnetic resonance imaging. They also measured several markers of inflammation and cardiac fibrosis.
Bottom Line: This was a large randomized controlled trial investigating the effects of high-dose omega-3 supplementation on changes in heart structure and function after a heart attack.
Finding 1: Omega-3 Supplements Improved Heart Function
Left ventricular systolic volume index (LVSVI) is a marker of the heart’s ability to pump blood.
The researchers discovered that high-dose omega-3 supplementation reduced LVSVI by 5.8%, compared to a placebo. This is a beneficial change, indicating improved heart function.
The chart below shows the changes in LVSVI in both groups:
There was a dose-response relationship between these benefits and increases in the omega-3 content of red blood cells (RBC).
Among those participants who achieved the highest increase in the omega-3 content of RBCs, the reduction in LVSVI was much higher at 13%.
Bottom Line: Supplementing with 4 grams of omega-3 for half a year after a heart attack significantly improved heart function, compared to a placebo.
Finding 2: Omega-3 Supplements Reduced Myocardial Fibrosis
Myocardial fibrosis (MF) is a condition characterized by the accumulation of scar tissue in the heart muscle. It reduces the heart’s ability to contract and pump blood.
Increased MF is often seen following a heart attack and increases the risk of heart failure.
The researchers assessed non-infarct myocardial fibrosis (NMF), which is myocardial fibrosis in undamaged areas of the heart.
The researchers were unable to measure NMF directly. Instead, they measured extracellular volume fraction, which is a marker of MF.
On average, the participants experienced a 5.6% improvement in NMF, compared to a placebo. The chart below shows the differences between groups:
They discovered that high-dose omega-3 supplementation reduced ST2 by 7.9%, further confirming its benefits for patients with heart disease. These findings are consistent with previous studies (4).
Both groups also experienced a significant improvement in infarct size (areas of dead heart tissue), but the difference was not statistically significant between groups.
All of these benefits were associated with an increase in the omega-3 content of red blood cells.
Bottom Line: Supplementing with omega-3 decreased heart tissue scarring (myocardial fibrosis), reducing the risk of heart failure.
Finding 3: Omega-3 Supplements Decreased Inflammation
The study found that supplementing with omega-3 reduced circulating levels of myeloperoxidase by 8.1%.
Myeloperoxidase is an enzyme that has been used as a marker of inflammation in the heart (5).
The authors speculated that the anti-inflammatory effects of omega-3 fatty acids explain the health benefits seen in the current study.
Bottom Line: Omega-3 supplements also decreased inflammation, potentially explaining their benefits for heart function.
This study didn’t have any major limitations.
However, a considerable proportion of the participants couldn’t return for a lab visit at the end of the study.
Additionally, the participants started supplementing with omega-3 two to four weeks after having a heart attack.
Changes in LVSVI and NMF were only modest compared to clinical care guidelines, but much greater benefits could have been achieved if the treatment had started earlier.
Finally, the omega-3 came from a prescription supplement with the brand name Lovaza, which was provided by the pharmaceutical company GlaxoSmithKline. It is unclear if regular omega-3 supplements are as effective.
Bottom Line: This study didn’t appear to have any major limitations. However, if the omega-3 treatment had started immediately after a heart attack, the participants might have achieved much greater benefits.
Summary and Real-Life Application
In short, this study showed that supplementing with 4 grams of omega-3 for 6 months helped repair some of the damage caused by a heart attack.
Many previous studies have confirmed the health benefits of omega-3 supplements, and most health authorities promote adequate dietary intake of omega-3 oils.
The present results strongly support the use of high-dose omega-3 supplements after a heart attack.
But even if you are healthy and fit, regularly eating fatty fish or supplementing with omega-3 might reduce your risk of developing chronic disease later in life.