Dietary omega 3 fatty acids and the developing brain.

Key Findings

This review provides a background on ω-3 fatty acids and current knowledge relating early fatty acid nutrition to cognitive and behavioral development. The possibility that western diets poor in ω-3 fatty acids and rich in ω-6 fatty acids contribute to poor CNS development and function is becoming increasingly recognized. The evidence to show low rates of conversion of 18:3ω-3 to DHA in individuals following western diets. Recent research to show genetic variations in the fatty acid desaturase pathway influences circulating and human milk essential fatty acids also raise the need to understand whether gene polymorphisms alter the requirements for particular ω-3 fatty acids, and if diet-gene interactions increase risk of poor neural development or disease in some individuals.

ABSTRACT

The ω-3 fatty acids are essential dietary nutrients and one of their important roles is providing the fatty acid with 22 carbons and 6 double bonds known as docosahexaenoic acid (DHA) for nervous tissue growth and function. Inadequate intakes of ω-3 fatty acids decrease DHA and increase ω-6 fatty acids in the brain. Decreased DHA in the developing brain leads to deficits in neurogenesis, neurotransmitter metabolism, and altered learning and visual function in animals. Western diets are low in ω-3 fatty acids, including the 18 carbon ω-3 fatty acid alpha linolenic acid found mainly in plant oils, and DHA, which is found mainly in fish. The DHA status of the newborn and breast-fed infant depends on the maternal intake of DHA and varies widely. Epidemiological studies have linked low maternal DHA to increased risk of poor child neural development. Intervention studies have shown improving maternal DHA nutrition decreases the risk of poor infant and child visual and neural development. Thus, sufficient evidence is available to conclude that maternal fatty acid nutrition is important to DHA transfer to the infant before and after birth, with short and long-term implications for neural function. However, genetic variation in genes encoding fatty acid desaturases also influence essential fatty acid metabolism, and may increase requirements in some individuals. Consideration of ω-3 fatty acid to include brain development, optimizing ω-3 and ω-6 fatty acids in gestation and lactation, and in fatty acid nutrition support for intravenous and formula-fed neonates is important.