Humans evolved with a staple source of the essential omega-3 fat docosahexaenoic acid (DHA) in their diets, namely seafood.
Animal based omega-3 fats are considered essential because they cannot be synthesized in appropriate quantities by your body and must be supplied through your diet.
The introduction of high-quality, easily digested nutrients from seafood into the human diet coincided with the rapid expansion of grey matter in the cerebral cortex — a defining characteristic of the modern human brain.
The DHA molecule has unique structural properties that provide optimal conditions for a wide range of cell membrane functions, and grey matter is a particularly membrane-rich tissue.
There’s no doubt you need omega-3 fat for proper brain function.
In fact, mounting evidence suggests that deficiency in this essential fat may lead to brain degeneration. According to a recent article published in the journal Nutrients1:
“An emerging body of research is exploring a unique role for DHA in neurodevelopment and the prevention of neuropsychiatric and neurodegenerative disorders.”