DHA also maintains the activity of a key cell membrane enzyme called Na+/K+ ATPase that extracts energy from ATP to drive the cellular sodium pump, which controls electrical impulses betweens cells. For example, it has been shown that feeding rats a DHA-deficient diet lowers activity of Na+/K+ ATPase by 40%.43 This enzyme is also linked to 60% of the energy consumed by the brain.44 Maintaining cellular energy levels is particularly important in preventing excitotoxicity (a pathological process that damages or kills nerve cells), since low energy can dramatically increase sensitivity to this destructive process.
Another essential cognitive process controlled by DHA is regulating the brain’s concentration of phosphatidylserine (PS), which is also vital for cell survival.45 Diets low in DHA reduce brain PS, which affects cell signaling for survival through enzymes including Na+/K+ ATPase and calcium uptake. Calcium is one of the most common and versatile cell-signaling systems. DHA, but not EPA, has been shown to be a major regulator of calcium oscillations (waves within cells),46 which regulate a vast array of cellular functions, including neurotransmitter release, mitochondrial function, gene activation, oxidative stress, and, in the developing brain, neuron migration and maturation.47Low DHA levels are also known to lower brain and cellular growth factors, such as brain-derived growth factor.