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


Essential polyunsaturated fatty acids (PUFAs) are termed 'essential' because they cannot be synthesized by the human body.[7] The omega-3 and omega-6 fatty acids comprise the two main families of essential fatty acids.[8] The omega-3 and omega-6 fatty acids are so named because of the position of the double bond from the methyl end of each molecule.[9] The first double bond of the omega-6 series is located at the sixth carbon atom. This configuration applies to linoleic acid (LA), the 18-carbon parent compound and its 20-carbon derivative, arachidonic acid (ARA).[8] Similarly, the 18-carbon parent compound of the omega-3 series is α-linolenic acid (ALA); its metabolic derivatives are eicosapentaenoic acid (EPA) (20 carbon), which in turn may be elongated to form DHA (22 carbon). Thus the PUFAs LA and ALA are elongated and desaturated to the long-chain PUFAs ARA, EPA and DHA[8] Both long-chain PUFAs in the omega-3 series share the first double bond at the third carbon atom.[8,9]

The essential fatty acid LA, of the omega-6 series, is found in grains and vegetable oils and is the precursor of ARA.[1] ARA is synthesized in the human body by a process of enzymatic elongation and desaturation, and is also supplied in the diet in red meat and meat products.[10,11] Similarly, the essential fatty acid parent of the omega-3 series, ALA, is present in flax seed, rapeseed oil and green leafy vegetables.[12] ALA undergoes elongation and desaturation to the long-chain PUFAs of the omega-3 series, EPA and DHA (Figure 1).[10] Although humans are able to metabolically convert the essential fatty acids to ARA, EPA and DHA via fatty acid desaturase enzymes, this process is relatively inefficient, and is unable to meet the maternal and fetal needs for DHA.[3,10,13] Thus DHA and EPA in the human diet are largely supplied through eating oily fish.[11,14] However, industrial contamination with mercury has led the US FDA to issue dietary advice to pregnant and lactating women, suggesting restriction of intake to two or fewer fish meals (˜340 g) per week.[14,101] Thus, pregnant women are at risk for lower levels of DHA.[3] This relative fatty acid deficiency is thought to play a role in maternal mental health during pregnancy and the postpartum period.

Figure 1.

Conversion of linoleic acid and α-linolenic acid to long-chain polyunsaturated fatty acids.


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