What is the best source of EPA and DHA?

October 19, 2025 •

3 min read

According to the American Heart Association, it is recommended that adults consume at least two servings of fatty fish per week to reduce the risk of heart problems. A key reason for this advice is the high concentration of EPA and DHA found in these fish, making seafood the primary and most direct answer to the question, "What is the best source of EPA and DHA?".

Quick Summary

Fatty fish like salmon and mackerel are the most direct and bioavailable sources of the omega-3 fatty acids EPA and DHA. For non-fish eaters, microalgae-based supplements and some plant foods offer alternatives, but the body's conversion of plant-based ALA is inefficient. Supplements from fish, krill, and algae are also excellent options for boosting intake.

Key Points

Fatty Fish are the Top Source: Oily fish like salmon, mackerel, and sardines provide the most direct and bioavailable forms of EPA and DHA.
Algal Oil is the Best Vegan Option: For those on a plant-based diet, algae-based oil is the only reliable source of preformed EPA and DHA.
ALA Conversion is Inefficient: Plant foods like flaxseeds and walnuts contain ALA, but the body's conversion to EPA and DHA is very limited and unreliable.
Supplements Offer a Consistent Dose: Fish oil, krill oil, and algal oil supplements provide a standardized and effective way to increase EPA and DHA intake.
Dietary Diversity is Key: A balanced diet combining various sources—fatty fish, algae, and ALA-rich plants—is the best strategy for comprehensive omega-3 intake.
Consider Sustainability: When choosing fish or supplements, look for sustainable sourcing certifications, such as from the Marine Stewardship Council (MSC).

Oily Fish: The Direct Pathway to EPA and DHA

For most individuals, the most efficient way to obtain sufficient eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) is through fatty fish consumption. Unlike plant sources requiring inefficient ALA conversion, fatty fish provide preformed long-chain omega-3s. The American Heart Association advises two weekly servings of fatty fish for heart health.

Top Fatty Fish Sources

Numerous types of fatty fish are excellent sources of EPA and DHA. Popular options include salmon, mackerel, and sardines, which also offer other beneficial nutrients. Other good sources are herring, anchovies, trout, and oysters.

Vegan and Vegetarian EPA and DHA Sources

Obtaining preformed EPA and DHA is more challenging for those avoiding fish. Plant-based diets typically contain ALA, which converts poorly to EPA and DHA. Therefore, direct plant-based sources are crucial. Microalgae, the original source of marine omega-3s for fish, provide the most reliable vegan option.

Algal Oil and Seaweed

Microalgae, such as those used in algal oil supplements, are a direct and sustainable plant-based source of EPA and DHA. These supplements offer a guaranteed dose of these omega-3s, bypassing the need for conversion. Seaweed varieties like nori also contain EPA and DHA.

The Role of ALA from Plants

Plant-based foods primarily offer ALA, which has some health benefits but is not a sufficient substitute for direct EPA and DHA due to inefficient conversion. Examples of ALA-rich foods include chia seeds, flaxseeds (especially ground), walnuts, and hemp seeds.

Comparison of EPA and DHA Sources

This table compares different sources of EPA and DHA:


Source Category	EPA & DHA Form	Bioavailability	Best For	Considerations
Fatty Fish	Preformed EPA and DHA	High	Omnivores	Potential mercury levels in some species (limit larger predatory fish).
Algal Oil Supplements	Preformed EPA and DHA	High	Vegans, Vegetarians, seafood-allergic individuals	Supplementation required; may be pricier per milligram than fish oil.
Fish Oil/Krill Oil Supplements	Preformed EPA and DHA	High	Individuals who dislike fish or need higher doses	Risk of contaminants if not purified; can cause fishy burps.
Plant-based ALA (e.g., Flax, Walnuts)	ALA (precursor)	Very low conversion rate to EPA/DHA	General health, but insufficient for boosting EPA/DHA levels.	Inefficient conversion means it cannot replace direct EPA and DHA sources.

The Role of Supplements

Supplements are a reliable way to ensure adequate EPA and DHA intake, particularly for those not consuming fish. Common types include fish oil, offering concentrated doses; cod liver oil, which also contains vitamins A and D; krill oil, which may have enhanced absorption due to phospholipid form; and algal oil, a vegan option from algae. Consulting a healthcare provider is recommended before starting supplements.

Conclusion

The ideal source of EPA and DHA varies based on diet. Fatty fish are the most bioavailable dietary sources for those eating animal products. Vegans and vegetarians can obtain direct EPA and DHA from algal oil and algae-based foods, bypassing the inefficient conversion of ALA from other plants like flaxseeds and walnuts. Combining whole foods and, if necessary, supplementation helps ensure optimal intake of these crucial fatty acids for overall health.

Frequently Asked Questions

Fatty fish like salmon, mackerel, herring, and sardines are among the richest dietary sources of EPA and DHA. Wild salmon often has slightly higher levels compared to farmed salmon.

Most plant foods contain ALA, which the body converts to EPA and DHA, but this process is highly inefficient. The most reliable plant-based sources are algal oil and seaweed, which provide preformed EPA and DHA.

Yes, supplements like fish oil, krill oil, and algal oil are effective alternatives for people who don't eat fish or need higher doses. They provide a concentrated source of EPA and DHA, though it is always best to consult a healthcare provider before starting supplements.

EPA and DHA support numerous bodily functions, including heart health, brain function, eye development, and reducing inflammation. DHA is particularly concentrated in the brain and retina.

ALA (alpha-linolenic acid) is a short-chain omega-3 found in plants. EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid) are long-chain omega-3s primarily found in marine life and algae. The body converts ALA into EPA and DHA, but at a very low rate.

Yes, larger, predatory fish like swordfish and king mackerel have higher mercury levels. It is recommended to choose fish lower in mercury, such as salmon, sardines, and canned light tuna, especially for pregnant women and young children.

Yes, and it's highly recommended. Adequate DHA intake during pregnancy and breastfeeding is crucial for the baby's brain and eye development. Pregnant women should focus on consuming 8 to 12 ounces of fish per week, choosing low-mercury varieties.