Difference Between Omega-3 and EPA Supplements
EPA (eicosapentaenoic acid) is one specific type of omega-3 fatty acid, while omega-3 supplements typically contain a combination of EPA and DHA (docosahexaenoic acid), each with distinct physiological roles and benefits. 1
Omega-3 Fatty Acids: Types and Sources
- Omega-3 fatty acids are polyunsaturated fatty acids obtained from two main dietary sources: seafood (marine sources) and certain plant oils 1
- The three main types of omega-3 fatty acids are:
- EPA (eicosapentaenoic acid): 20-carbon fatty acid found primarily in fatty fish and fish oils 1
- DHA (docosahexaenoic acid): 22-carbon fatty acid also found in fatty fish and fish oils 1
- ALA (α-linolenic acid): 18-carbon fatty acid found in plant sources like canola, walnut, soybean, and flaxseed oils 1, 2
Key Differences Between EPA and Omega-3 Supplements
Composition
- EPA supplements contain only eicosapentaenoic acid 3
- Standard omega-3 supplements typically contain a mixture of EPA and DHA 4
- Only one prescription EPA-only product (Vascepa/icosapent ethyl) is available in the US, while most other omega-3 products contain both EPA and DHA 3
Effects on Blood Lipids
- EPA-only supplements do not raise LDL cholesterol levels, even in patients with very high triglyceride levels (>500 mg/dL) 3, 4
- Omega-3 supplements containing both EPA and DHA may lower triglycerides but can also increase LDL cholesterol levels 5, 4
Cardiovascular Benefits
- Both EPA and combined EPA+DHA supplements can lower triglyceride levels 5
- EPA-only therapy has shown significant cardiovascular benefit in clinical trials, particularly in the JELIS study which demonstrated a 19% reduction in major coronary events when EPA was added to statin therapy 1
- Higher doses of combined EPA and DHA may be required for secondary cardiovascular disease prevention, especially in patients on high-intensity statins 1
Cognitive Function
- DHA appears more important than EPA for cognitive function due to its high concentration in the brain (comprising approximately 25% of total fatty acids in the human cerebral cortex) 1
- DHA levels above the median have been associated with improvements in verbal fluency, language, memory, and visual-motor coordination, while EPA levels alone did not show these benefits 1
- However, combined EPA and DHA supplementation led to the best cognitive improvement in clinical trials, possibly due to conversion of EPA to DHA 1
- The Chicago Memory and Aging project found that total intake of omega-3 fatty acids and DHA were associated with reduced risk of Alzheimer's disease, but EPA alone was not 1
Quality and Regulation Differences
- Prescription omega-3 products (including EPA-only formulations) undergo rigorous FDA approval processes and must demonstrate safety and efficacy 4
- Dietary supplements containing omega-3s are not FDA-approved as drugs and have less regulatory oversight 4
- Dietary supplements may contain variable concentrations of EPA and DHA, and potentially other contaminants 5, 4
- Supplements should not be substituted for prescription products when treating medical conditions 4
Clinical Recommendations
- For cardiovascular health, the American Heart Association recommends:
- For cognitive health:
Important Considerations
- The conversion of ALA (plant-based omega-3) to EPA and DHA is inefficient in humans, making direct consumption of EPA and DHA important, especially for vegetarians 2
- Vegetarians may need to double their ALA intake or consider algae-derived EPA and DHA supplements 2
- When selecting an omega-3 supplement, consider whether raising LDL cholesterol is a concern; if so, an EPA-only formulation may be preferable 3, 4
- For specific medical conditions, prescription products are recommended over dietary supplements due to consistent potency and purity 4