The Developing Brain and Dietary Omega-3 Fatty Acids

Abstract

The ω-3 fatty acids are essential dietary nutrients and are present in humans diets in three major forms, the 18-carbon chain α-linolenic acid (18:3ω-3) which is found in vegetable oils and other plant foods, and the 20- and 22-carbon chain eicosapentaenoic acid (EPA, 20:5ω-3) and docosahexaenoic acid (DHA, 22:6ω-3), respectively, for which the richest dietary source is fish. One of most important roles of the ω-3 fatty acids is providing DHA for brain development and function. DHA is specifically enriched in brain grey matter ethanolamine phosphoglycerides and phosphatidylserine, represents 7–10% of human brain total fatty acids, and plays important roles in neurogenesis, neurite outgrowth, monoaminergic neurotransmission, and protection against oxidative and inflammatory insults. Dietary deficiency of ω-3 fatty acids results in decreased DHA and replacement by long chain ω-6 fatty acids which do not provide a functional substitute for the essential roles of DHA in the brain. During early development, DHA is provided by placental transfer and then in breast milk, placing the importance of ω-3 fatty acid nutrition on the mother, after weaning the importance of ω-3 fatty acid nutrition is shifted to the diet of children. Modern diets favoring high intakes of ω-6 fatty acids and low intakes of fish raise concern due to limited supplies of preformed DHA and EPA and interference with endogenous capacity to use ω-3 fatty acids. Evidence is growing to suggest that these dietary patterns may contribute to poor infant and child neural development, potentially impacting both behavior and cognitive abilities.