Linoleic acid (LA) which is an omega-6 fatty acid and Alpha-Linolenic acid (LnA) which is an omega-3 fatty acid are both needed in the diet since neither can be produced by the body. That is why they are called essential fatty acids. On the other hand EPA , DHA and AA can be produced by the body and they are nonessential fatty acids. DHA and EPA are long chain polyunsaturated fatty acids (LC-PUFAs) The input of omega-6 fatty acids are important in inflammation, clotting, cell communication and delivery. Omega-3 ‘s are useful in counter- balancing the effects of omega-6′s.
The effect of DHA and EPA is to prevent prematurity and increase fetal birth weight. That is why many women who have premature delivery have a deficiency of omega-3′s and increased levels of the omega-6′s, namely the omega-6 AA (arachidonic acid) and DPA (docosapentaenoic acid). Also women with PIH (pregnancy induced hypertension) have low levels of omega-3′s. Preeclampsia risk is also higher if the levels of omega-3′s are low. These levels must be increased prior to pregnancy to provide benefits.
A 15% increase of the ratio of omega-3′s versus omega-6′s was found to cut the risk of preeclampsia by 46%. The supplementation needs to begin prior to conception in order to be effective against preeclampsia, PIH (pregnancy induced hypertension) and IUGR (intrauterine growth restriction). When infants have adequate DHA intake prior to birth, they then have lower risk of type 1 diabetes, better endocrine, immunity and heart function later in life.
Also maternal dietary DHA while breastfeeding confers improved retinal and brain development to the infants. Best sources of DHA are deep ocean fish that feed on specific algae called Schizotryum that are found in the deep ocean. These algea are also grown in large containers and used to enrich foods. Salmon and sardines are good sources. Fish oil, flaxseed oil and walnut oil are rich in omega-3′s. Daily recommended values (DRVs) are at least 300 mg of DHA and EPA daily during pregnancy, 20mg per kg for t erm infants and 40 mg per kg for preterm infants.
1) Williams MA, Zingheim RW, King IB, Zebelman AM. Omega-3 fatty acids in maternal erythrocytes and risk of preeclampsia. Epidemiol. 1995;232-237. 2) Carlson Sr, Workman SH, and Tolley EA. Effect of long-chain n-3 fatty acid supplementation on visual acuity and growth of preterm infants with and withourt bronchopulmonary dysplasia. Amer J Clin Nutr. 1996;63:687- 607.