Meeting the fetal requirement for polyunsaturated fatty acids in pregnancy.

PURPOSE OF REVIEW: The aim of this review is to summarize recent evidence on the importance of individual long chain polyunsaturated fatty acid (LCPUFA) to the developing fetus and the maternal dietary requirement for these. RECENT
FINDINGS: Large-scale randomized controlled trials and innovative genetic and stable isotope studies are providing new insights in this field.
SUMMARY: Large randomized controlled trials of LCPUFA supplementation in pregnancy suggest that higher n-3 LCPUFA intake reduces the risk of preterm birth and increases the length of gestation, with secondary effects on birth weight. There is little evidence of an effect on postnatal visual function and cognition, but interpretation is complicated by maternal metabolic adaptations and adipose tissue status in the newborn. The links between polymorphisms in the FADS genes and tissue fatty acid composition suggest that LCPUFA synthesis influences overall availability. Stable isotope studies have also demonstrated the capacity for LCPUFA synthesis in pregnancy, the fact that n-6 synthesis is greater than n-3, metabolic channeling of individual fatty acids to different fates, and selective placental transfer. Studies linking FADS genotype to cognition imply that n-3 LCPUFA synthesis could have an effect on infant cognition, but more large-scale genetic studies are needed.