47) Is docosahexaenoic acid synthesis from a-linolenic acid sufficient to supply the adult brain?

A.F. Domenichiello et al. / Progress in Lipid Research 59 (2015) 54–66

Docosahexaenoic acid (DHA, 22:6n-3) is highly concentrated in the brain, and is important for brain function in part by regulation of cell survival and neuroinflammation.

DHA cannot be synthesized de novo in mammals, and therefore, must be obtained in the diet primarily through fish, Nutraceuticals and functional foods
DHA is the main n-3 PUFA in the brain as it is concentrated at levels of about 10,000 nmol/g brain (10–15% of brain fatty acids or about 5 g in an adult brain [7,8]), at least 50-fold more than EPA and 200-fold more than ALA

DHA is highly concentrated in the brain and retina, and reductions in brain and retina DHA in rodents and non-human primates are associated with cognitive impairments such as severe learning deficits and anxiety, as well as visual impairments such as lower.
Electroretinogram amplitude and longer electroretinogram recovery time (reviewed in [30]). Supplemental DHA is associated with improved visual acuity in pre-term infants [31], and infant formula containing DHA and arachidonic acid.