Marine Oils

In: Drugs and Lactation Database (LactMed) [Internet]. Bethesda (MD): National Library of Medicine (US); 2006–.


Marine oils, such as fish oil or algal oil, are a rich source of omega-3 fatty acids, especially the essential fatty acids, docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA). Algal oil is high in DHA and low in EPA, whereas fish oil has more EPA than DHA. DHA and EPA are normal components of breastmilk where concentrations reflect maternal intake. The DHA level in breastmilk is typically between 0.2% and 0.3% in Western countries.[1] This is usually sufficient to meet the DHA requirements of term breastfed infants, but not the higher requirements of pre-term infants, where additional maternal supplementation is needed.[2] Maternal supplementation increases breastmilk levels of DHA and EPA, although it appears that milk concentrations depend more on long-term intake than short-term (past 3-days) intake.[3,4] Higher milk levels result in higher infant plasma and erythrocyte levels of omega-3 fatty acid-derived phospholipid; one study found that breastmilk DHA was a better predictor of infant erythrocyte DHA than direct supplementation of the infants with fish oil.[5] Current dietary recommendations for nursing mothers is 250 to 375 mg daily of DHA plus EPA.[6] Lactating women require a daily dosage of about 1000 mg DHA plus EPA to reach a milk DHA plus EPA of 1 g/dL at 4 weeks postpartum.[7]

Supplementation with omega-3 fatty acids has been studied for reduction of postpartum depression in nursing mothers and for improving various infant outcomes. A meta-analysis of 35 randomized, controlled trials found that women with a diagnosis of severe depression obtained benefit from omega-3 fatty acids, but those with mild depression did not.[8]

Fish oil up to 3 grams daily is “generally recognized as safe” (GRAS) as a food by the U.S. Food and Drug Administration. The most common complaint is burping a fishy taste after ingestion. However, breast milk odor is not changed by maternal fish oil consumption.[20] Rarely, allergic reactions are reported with nut oil-derived omega-3 fatty acids in patients allergic to nuts.

Dietary supplements do not require extensive pre-marketing approval from the U.S. Food and Drug Administration. Manufacturers are responsible to ensure the safety, but do not need to prove the safety and effectiveness of dietary supplements before they are marketed. Dietary supplements may contain multiple ingredients, and differences are often found between labeled and actual ingredients or their amounts. A manufacturer may contract with an independent organization to verify the quality of a product or its ingredients, but that does not certify the safety or effectiveness of a product. Because of the above issues, clinical testing results on one product may not be applicable to other products. More detailed information about dietary supplements is available elsewhere on the LactMed Web site.

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