Essential fatty acid transfer and fetal development.

ABSTRACT

Docosahexaenoic acid (226n-3) and arachidonic acid (204n-6) are important structural components of the central nervous system. These fatty acids are transferred across the placenta, and are accumulated in the brain and other organs during fetal development. Depletion of 226n-3 from the retina and brain results in reduced visual function and learning deficits these may involve critical roles of 226n-3 in membrane-dependent signaling pathways and neurotransmitter metabolism. Transfer of 226n-3 across the placenta involves specific binding and transfer proteins that facilitate higher concentrations of 226n-3 and 204n-6, but lower linoleic acid (182n-6) in fetal compared with maternal plasma, or in the breast-fed or formula-fed infant. However, human and animal studies both demonstrate that maternal diet impacts fetal 226n-3 and 204n-6 accretion. After birth, parenteral lipid, human milk and infant formula feeding all result in a marked decrease in plasma 226n-3 and 204n-6 and an increase in 182n-6. Estimation of fetal tissue fatty acid accretion suggests that current preterm infant feeds are unlikely to meet in utero rates of 226n-3 accretion. Consideration needs to be given to whether fetal plasma 226n-3 and 204n-6 enrichment and the low 182n-6 facilitates accretion of 226n-3 and 204n-6 in developing tissues.