What is the comparative efficacy of omega-3 fatty acids versus krill oil?

From the Guidelines

Omega-3 fatty acids are the preferred choice over krill oil for reducing cardiovascular risk, as evidenced by the most recent and highest quality study, the REDUCE-IT trial 1. When considering the use of omega-3 fatty acids versus krill oil, it is essential to prioritize the reduction of morbidity, mortality, and improvement of quality of life. The REDUCE-IT trial, published in 2021, demonstrated that icosapent ethyl (IPE), a highly purified ethyl ester of EPA, significantly reduced cardiovascular events, including cardiovascular death, nonfatal MI, or nonfatal stroke, with a hazard ratio of 0.74 (95% CI: 0.65-0.83) 1. Key benefits of omega-3 fatty acids include:

• Reduction in triglycerides by a median of 19.7% compared to placebo at 1 year 1
• Median reductions in LDL-C of 5.0 mg/dL (6.6%) and in non–HDL-C of 15.5 mg/dL (13.1%) 1
• Potential anti-inflammatory effects, including a reduction in log-transformed high-sensitivity C-reactive protein (hs-CRP) from 0.8 to 0.6 mg/L in the IPE group versus an increase from 0.8 to 1.0 mg/L in the placebo group 1 In contrast, the STRENGTH trial, which compared omega-3 carboxylic acids to placebo, found no significant difference in cardiovascular events (HR: 0.99; 95% CI: 0.90-1.09; P = 0.84) 1. The differences in outcomes between the REDUCE-IT and STRENGTH trials may be attributed to the different therapies studied, lower blood levels of EPA achieved in STRENGTH, and different biological effects of a mixture of EPA/DHA as compared with EPA alone 1. While krill oil may offer some benefits, the current evidence suggests that omega-3 fatty acids, particularly IPE, are the more effective choice for reducing cardiovascular risk. Therefore, omega-3 fatty acids are recommended over krill oil for patients with persistent hypertriglyceridemia or those at high risk of cardiovascular events.

From the Research

Omega-3 Fatty Acids

• Omega-3 fatty acids, including eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), play a crucial role in cardiovascular health and disease 2, 3
• They have been shown to have cardioprotective effects, including reducing the risk of arrhythmias, atherosclerosis, inflammation, and thrombosis 3
• Omega-3 fatty acids may also improve endothelial function, lower blood pressure, and significantly lower triglycerides 3

Comparison with Krill Oil

• There is limited direct comparison between omega-3 fatty acids and krill oil in the provided studies
• However, krill oil is a source of omega-3 fatty acids, particularly EPA and DHA, and may have similar cardioprotective effects 4

Cardiovascular Health

• Increasing intake of omega-3 fatty acids, particularly EPA and DHA, may slightly reduce the risk of coronary heart disease mortality and events 5, 6
• Omega-3 fatty acids may also reduce serum triglycerides and have anti-inflammatory effects, which can contribute to cardiovascular health 5, 6
• The evidence for primary prevention of cardiovascular disease through omega-3 fatty acid supplementation is relatively weak, but there is stronger evidence for secondary prevention in high-risk patients 4

Dosage and Sources

• The optimal dosage of omega-3 fatty acids for cardiovascular health is not well established, but doses ranging from 0.5 g to 5 g per day have been studied 5, 6
• Sources of omega-3 fatty acids include fatty fish, supplements, and concentrated pharmaceutical preparations 4