Eicosapentaenoic acid (EPA), docosapentaenoic acid (DPA), and docosahexaenoic acid (DHA) are long-chain omega-3 polyunsaturated fatty acids essential for proper human function. These compounds are integral components of cell membranes, influencing fluidity and playing a part in cell signaling processes. Low levels of these fatty acids are common in many Western populations and represent a measurable health concern associated with insufficient intake.
Specific Health Consequences of Low Levels
Insufficient levels of EPA, DPA, and DHA pose risks, particularly to the cardiovascular network. These fatty acids help regulate blood lipid levels, blood pressure, and inflammation. Individuals with lower circulating levels of EPA and DHA have a greater likelihood of experiencing cardiovascular events, including fatal coronary heart disease.
The anti-inflammatory effects of omega-3s are linked to their ability to compete with omega-6 fatty acids in the production of signaling molecules. This competition shifts the balance toward less inflammatory activity. When EPA and DHA levels are low, the production of compounds that resolve inflammation is reduced. Maintaining adequate levels is associated with lower total mortality and reduced risk of chronic conditions.
Brain and cognitive functions are highly dependent on adequate omega-3 status, as DHA is a primary structural component of neural cell membranes. Lower levels are linked to reduced brain volume, which can accelerate progression toward dementia. Low omega-3 status is also associated with mood regulation issues and impaired cognitive abilities, including difficulties with focus and memory.
Studies have linked lower blood levels of EPA and DHA to conditions such as attention-deficit/hyperactivity disorder (ADHD) and major depression. EPA is noted for its ability to reduce neuroinflammation, a factor in some psychiatric conditions. DPA is associated with a lower incidence of coronary heart disease and may act as a reservoir for conversion into EPA and DHA, supporting neural health and reducing platelet aggregation.
Primary Drivers of EPA, DPA, and DHA Deficiency
The primary reason for low omega-3 status is insufficient dietary intake, especially in populations consuming a modern diet. This diet often lacks sufficient cold-water fatty fish, the most direct source of EPA and DHA. Without regular consumption of these marine sources, the body relies on conversion from the plant-based omega-3 alpha-linolenic acid (ALA).
The body’s ability to convert ALA, found in foods like flaxseeds and walnuts, into EPA and DHA is inefficient. Conversion rates are very low; only about 5% to 8% of ALA converts to EPA, and 0.5% to 5% converts to DHA. Most ingested ALA is used for energy or stored, making reliance on ALA an unreliable strategy for maintaining optimal EPA and DHA levels.
Genetic variations also play a substantial role in determining omega-3 status. The FADS gene cluster encodes the desaturase enzymes that perform the rate-limiting steps in converting ALA to the longer-chain omega-3s. Certain genetic variations within the FADS genes can reduce the efficiency of these enzymes, significantly lowering the body’s capacity to synthesize EPA and DHA from ALA.
Certain medical conditions or medications can impair the absorption of dietary fats, including omega-3s. Conditions affecting fat digestion and absorption in the gastrointestinal tract limit the amount of EPA and DHA that enters the bloodstream, regardless of dietary intake. The combination of a low-intake diet and poor conversion efficiency explains the widespread prevalence of low omega-3 levels.
Measuring Omega-3 Status: The Omega-3 Index
The Omega-3 Index is used to determine an individual’s long-term omega-3 status. This index is defined as the percentage of EPA and DHA present in red blood cell (RBC) membranes relative to the total fatty acids present. Because RBCs have a lifespan of approximately 120 days, the Index provides a stable, long-term reflection of tissue status, unlike plasma tests that reflect recent meals.
The measurement is performed using a simple blood sample, often a finger-stick blood spot analysis. Results are categorized into ranges: below 4% is considered low and corresponds to a higher risk of health issues. The intermediate range is 4% to 8%, and an optimal or protective score is 8% or higher.
Reaching the optimal range is associated with the lowest risk of chronic diseases, including cardiovascular disease. Measuring this index allows healthcare professionals to monitor status and tailor recommendations to achieve the target range.
Effective Strategies for Increasing Levels
Correcting a low Omega-3 Index requires increasing the direct intake of EPA and DHA. The most effective way is through regular consumption of fatty fish, such as salmon, mackerel, sardines, and herring. Eating two to three servings of these cold-water fish per week is an excellent dietary foundation for boosting levels.
Although plant sources like flax and walnuts contain ALA, direct consumption of preformed EPA and DHA from marine sources is the only practical way to elevate tissue levels due to poor conversion capability. For individuals who do not consume fish, algae-derived supplements offer a plant-based source of preformed DHA.
Supplementation is a method for rapidly achieving therapeutic levels, especially when aiming for an index of 8% or higher. Omega-3 supplements come in various chemical forms, primarily triglycerides (TG) and ethyl esters (EE). The natural form of omega-3s found in fish is the triglyceride form.
Triglyceride-form supplements, including the re-esterified triglyceride (rTG) form, demonstrate higher bioavailability compared to the ethyl ester form. Ethyl esters are a processed, concentrated form that requires an extra step of enzymatic digestion, which is less efficient, especially when not consumed with fat. Dosage should be guided by the Omega-3 Index result, as lower baseline scores require higher daily intake to reach the protective 8% range.