Study
Effect of High-Dose Omega-3 Fatty Acids vs Corn Oil on Major Adverse Cardiovascular Events in Patients at High Cardiovascular Risk: The STRENGTH Randomized Clinical Trial.
4 g/day EPA+DHA carboxylic acid (Epanova) showed no cardiovascular benefit vs corn oil and was stopped early for futility.
Summary Does high-dose fish oil prevent heart attacks and strokes? Show / hide ↓
Researchers gave 13,708 people at high heart risk either 4 grams of omega-3 fats daily or corn oil. All participants took cholesterol-lowering medicines and had high triglycerides, which are fats in the blood. After about three and a half years, the omega-3 group had about the same number of heart attacks, strokes, and related problems as the corn oil group, 12.0% versus 12.2%. The study stopped early because omega-3 showed no likely benefit. Irregular heartbeats called atrial fibrillation were more common with omega-3, as were stomach and bowel problems.
What this means for you: For people like those studied, high-dose omega-3 did not prevent major heart problems. Do not buy high-dose fish oil for this purpose based on this study, and discuss any supplement with a healthcare professional.
solid evidenceSTRENGTH randomized 13,708 statin-treated patients with high cardiovascular risk and hypertriglyceridemia to 4 g/day of omega-3 carboxylic acid (EPA+DHA, Epanova) or corn oil placebo. The primary composite endpoint (CV death, nonfatal MI, nonfatal stroke, coronary revascularization, unstable angina) occurred in 12.0% vs 12.2% (HR 0.99, 95% CI 0.90-1.09, P=0.84). The trial was stopped early for futility after 3.5 years. Triglycerides decreased 19% with omega-3 vs 0.9% with corn oil (P<0.001), but this did not translate to event reduction. Atrial fibrillation was significantly increased (2.2% vs 1.3%, P<0.001), as were gastrointestinal adverse events. A secondary analysis (JAMA Cardiol 2021) found no benefit even in patients achieving the highest EPA blood levels.
Among patients with high cardiovascular risk, the addition of omega-3 fatty acids to statin therapy did not reduce the composite outcome of major adverse cardiovascular events.
The contrast with REDUCE-IT raises the possibility that pure EPA is more effective than EPA+DHA combined, or that the mineral oil placebo in REDUCE-IT inflated its apparent benefit. Both trials found increased atrial fibrillation.
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