The importance of PUFA in neuronal health and function is suggested by the rigid maintenance of a unique membrane fatty acid composition with high levels of palmitate and the polyunsaturated fatty acids (PUFA), including DHA and arachidonic acid
Brain phospholipids are much more (about 300 times) enriched in DHA than EPA.
DHA (DeMar et al., 2004) are much better retained in the brain, making a case for direct intake of these long chains PUFA rather than their shorter-chained precursors, if one were to ensure more efficient accumulation of these PUFA in the brain.
In cases of liver damage, failure or age-related impairment of liver function, one may need dietary intake of DHA to establish normal levels of DHA in the brain. Furthermore, neuronal membrane n-3 PUFA content may decrease with age and neurodegenerative diseases high levels of DPA (n-6) instead of DHA will lead to cognitive impairment, even though these molecules differ only by a single double bond.
DHA-derived resolvins play an important role in the resolution process of inflammation,which is concerned with specific mechanisms to promote return to homeostasis. DHA appears to be the critical PUFA for cognitive enhancement, at least during development DHA steeply increased prior to the period of synaptogenesis while other fatty acids reached plateau, implying its important role during this critical period of development. Thus, depletion of DHA during these critical periods of brain growth could catastrophically interfere with neurogenesis and synaptogenesis.
DHA was shown to play an important role in myelinogenesis.
Females must provide DHA for the growth of the unusually large brains of
their offspring from maternal fat stored during childhood, so their need for DHA is particularly great increasing doses of DHA and found that appropriate doses (150 or 300 mg/kg/d) significantly improved learning and memory.