Figure 1.

EPA and DHA can be synthesized from ALA, and adopt distinct orientations in the lipid bilayer. Production of EPA and DHA from ALA is an inefficient process, thus the most effective route to obtaining these O3FAs is often through the diet or pharmaceutical formulations. Within the membrane, EPA and DHA adopt distinct orientations and have contrasting effects on membrane fluidity. EPA has an extended, stable conformation and maintains normal cholesterol distribution and overall membrane fluidity, while DHA rapidly isomerizes on a nanosecond time scale, increases fluidity, and displace cholesterol into distinct domains, often rich in sphingolipids. DHA is known to often concentrate in retina and neuronal cell membranes, while EPA may concentrate in the membranes of endothelial cells and other vascular cells. FADS1, Δ⁵-desaturase; FADS2, Δ⁶-desaturase; ELOVL1, elongase of very long chain fatty acids protein 1; ELOVL2, elongase of very long chain fatty acids protein 2; ACOX1, peroxisomal acyl-coenzyme A oxidase 1; HSD1784, peroxisomal multifunctional enzyme type 2.