Assessing Omega-3 Fatty Acid Supplementation During Pregnancy and Lactation to Optimize Maternal Mental Health and Childhood Cognitive Development

Chelsea M Klemens; Kataneh Salari; Ellen L Mozurkewich


Clin Lipidology. 2012;7(1):93-109. 

In This Article

Maternal & Fetal Concentrations of Essential Fatty Acids & Long-chain PUFAs

Several investigations have demonstrated that fetal and maternal plasma and red blood cell levels of essential fatty acids and long-chain PUFAs are highly correlated.[68] Notably, fetal long-chain PUFA levels typically exceed maternal levels.[42,68] These findings have demonstrated that the long-chain PUFAs are preferentially transported across the placenta.[68] Similarly, DHA is preferentially transported relative to ARA.[44,68] The placenta is unable to elongate and desaturate essential fatty acids to long-chain PUFAs.[2,71] Thus the fetus must rely upon transport of preformed ALA and DHA from the maternal compartment.[71] Fetal accretion of the long-chain PUFAs DHA and ARA is dependent upon adequate provision of DHA and ARA preformed in the maternal diet, as the fetus only converts ALA to DHA to a limited degree.[69] However, not all placental transport reflects recent maternal diet. Long-chain PUFA stores laid down in maternal adipose tissue during early fetal life are mobilized via lipolysis in the third trimester for transport to the fetus.[71] Current knowledge of the activities of FABPs suggests that that DHA is transported preferentially across the placenta compared with other long-chain PUFAs and EFA in the following hierarchical fashion: DHA > ARA > ALA > LA.[2,71] The relative efficiency of placental transport of fatty acids is most likely influenced by individual genetic variations.[2]

Additionally, fatty acid transport to the fetal compartment is responsive to variations in maternal blood fatty acid status.[72] In an observational study of Tanzanian mothers with low, intermediate and high fish intake, Kuipers et al. compared maternal and fetal red blood cell fatty acid composition, as well as the fatty acid composition of fetal cord blood at delivery and infant DHA status at 3 months of age.[72] The investigators observed that in conditions of low-to-intermediate maternal fish intake, biomagnification of DHA via placental transport occurs.[72] By contrast, in conditions of high maternal fish intake, bioattenuation of transport across the placenta occurs, suggesting that there is a DHA equilibrium that is optimal for fetal growth and development.[72] The authors speculate that rather than an optimal DHA level, an appropriate DHA:ARA ratio is necessary for fetal health.[72] However, they concede that the optimal maternal and fetal DHA levels are not known.[72] In the absence of definitive data, they recommend adhering to the consensus guidelines of Koletzko et al., recommending maternal DHA intake of at least 200 mg/day.[10]


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