The roles of polyunsaturated fatty acids in brain development

Abstract

n-6 and n-3 polyunsaturated fatty acids （PUFAs） are essential nutrients for normal　brain development and function. Linoleic acid （LA） and α-linolenic acid （ALA） are the popular n-6 and n-3 PUFAs found in diet, and arachidonic acid （ARA） and docosahexaenoic acid （DHA） are the principal n-6 and n-3 PUFAs in the brain, respectively. ARA and DHA are rapidly deposited during brain development and are important regulators for embryonic neural stem cells. ARA and DHA share many enzymes in synthesis from the precursors, membrane phospholipid remodeling, and metabolism into lipid mediators, resulting in that ARA and DHA in the brain are generally competitive in these metabolic steps, and the dietary balance of n-6/n-3 PUFAs is considered to be important. However, intake of several vegetable oils, which are abundant in n-6 PUFAs, and that of fishes, which are abundant in n-3 PUFAs, have been increased and decreased, respectively, in many countries. I have recently reported that pregnant mice that consume a diet high in LA and low in ALA impairs neocortical development in the offspring by promoting the neurogenic-to-gliogenic fate transition of neural stem cells and also induces hedonic feeding behaviors in the offspring by upregulating midbrain dopaminergic system. In the present review, I summarize the functions of dietary n-6 and n-3 PUFAs in brain development.