LCPUFAs

LCPUFAs, or long-chain polyunsaturated fatty acids, are fatty acids with 20 or more carbon atoms and multiple cis double bonds. They include the omega-3 and omega-6 families, most notably EPA and DHA (omega-3) and arachidonic acid (ARA, omega-6). They play essential roles in membrane structure and cellular signaling.

Two essential fatty acids must be obtained from the diet: linoleic acid (LA, 18:2 n-6) and alpha-linolenic acid (ALA, 18:3 n-3). The body can elongate and desaturate LA and ALA to longer-chain derivatives such as AA, EPA, and DHA, but conversion rates—especially from ALA to EPA and DHA—are limited, making direct intake of EPA and DHA important for many people.

Dietary sources and forms: EPA and DHA are abundant in fatty fish, fish oil, and some microalgae, and are also added to some infant formulas and fortified foods. LA and ALA are found in various plant oils, nuts, and seeds. In the body, LCPUFAs are incorporated into cell membranes, with high concentrations in neural tissue and retina, and they act as precursors to bioactive lipids.

Physiological roles and health implications: LCPUFAs contribute to membrane fluidity, neurodevelopment, and vision, and they serve as precursors to eicosanoids that regulate inflammation and immunity. DHA is especially important for brain and retinal development; EPA is often associated with anti-inflammatory effects, while ARA-derived mediators can promote inflammatory responses under certain conditions. Adequate intake of EPA and DHA is linked to cardiovascular and cognitive benefits, with emphasis on balance between omega-3 and omega-6 intake.

Notes on intake: guidelines vary by region; dietary strategies aim to ensure sufficient EPA and DHA while moderating excessive omega-6 intake to support overall health.