Figure 2: Synthesis of PUFAs in the liver. Precursors of n-3 and n-6 polyunsaturated fatty acid (PUFA) α-linolenic (ALA; 18:3 n-3) and linoleic acid (LNA; 18:2 n-6) can be desaturated and elongated. This leads to the synthesis of long-chain PUFAs, including docosahexaenoic acid (DHA; 22:6 n-3), but also arachidonic acid (AA; 20:4 n-6) which are carried into the blood as free forms or lipoproteins. Both, n-3 and n-6 long-chain PUFAs, compete for their synthesis (for desaturation and elongation), meaning that PUFAs intake significantly impacts their cerebral incorporation level.