Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are omega-3 fatty acids found in certain foods and dietary supplements. These compounds are important for human health and influence various bodily functions, making them a key part of a balanced diet.
Defining EPA and DHA
Eicosapentaenoic acid (a 20-carbon chain) and docosahexaenoic acid (a 22-carbon chain) are long-chain polyunsaturated omega-3 fatty acids. Their chemical structures contain multiple double bonds, which is why they are called “polyunsaturated.” The “omega-3” designation refers to the location of the final double bond in their molecular structure.
The human body can create EPA and DHA from alpha-linolenic acid (ALA), an omega-3 found in plant foods. However, this conversion process is inefficient, with a rate often less than 15%. This makes obtaining EPA and DHA directly from dietary sources the most practical way to ensure adequate levels.
Primary Dietary Sources
The most concentrated dietary sources of EPA and DHA are marine-based. Fatty fish are particularly rich in these omega-3s, including:
- Salmon
- Mackerel
- Herring
- Sardines
- Trout
These fish build up high levels of EPA and DHA through the marine food chain. Microalgae are the original producers of these fatty acids, which are then concentrated as they move from smaller to larger fish.
For those on vegetarian or vegan diets, algal oil provides a direct plant-based source of EPA and DHA. Krill oil is another marine-based supplement option. Some foods, like certain brands of milk and infant formulas, are fortified with DHA. While nuts and seeds like flaxseed are high in ALA, they are not direct sources of EPA and DHA.
Health Significance of EPA and DHA
DHA is a structural component of the human brain and the retina of the eye, making up a significant portion of the brain’s weight. It is important for brain development in infants and is associated with cognitive function throughout life.
EPA’s main role relates to managing inflammation as a precursor to signaling molecules called eicosanoids. Scientific evidence supports the role of omega-3s, including EPA, in reducing blood triglyceride levels. Some studies also indicate modest blood pressure reductions in people who take fish oil supplements.
While they have individual functions, EPA and DHA often work together. Both are components of cell membranes, influencing their fluidity and function. Their combined effects are important for cardiovascular health, as research shows regular seafood consumption is associated with a lower risk of heart-related issues. The balance between these two fatty acids is an ongoing area of scientific investigation.
Intake Guidelines and Supplement Options
Health organizations often recommend eating fatty fish at least twice a week. The specific amount of EPA and DHA needed can differ based on age, life stage, and health. For instance, the need for DHA is higher during pregnancy and lactation to support a baby’s brain and eye development.
If dietary intake is insufficient, supplementation may be considered. Common supplement options include fish oil, krill oil, and algal oil, a suitable choice for those avoiding animal products. When selecting a supplement, check the label for the specific amounts of EPA and DHA per serving and for information about purity and testing for contaminants like mercury.
It is advisable to consult with a healthcare provider before beginning any new supplement regimen. This is particularly important for those taking medications, such as blood thinners, as high doses of omega-3s can increase the risk of bleeding. A healthcare professional can provide personalized guidance based on an individual’s health status and dietary habits.