The Food and Drug Administration and Environmental Protection Agency recently issued an updated draft of advice on fish consumption for pregnant and breastfeeding women, after survey data indicated that the majority of pregnant women do not eat much fish and thus may have inadequate intake of the omega 3 fatty acids eicosapentaenoic acid [EPA] and ducosahexaenoic acid [DHA].

Omega 3 fatty acids are essential components of membranes in all cells of the body and are vitally important for normal development of the brain and retinal tissues (especially myelin and retinal photoreceptors) and for maintenance of normal neurotransmission and connectivity. They also serve as substrates for the synthesis of a variety of anti-inflammatory and inflammation-resolving mediators, favorably alter the production of thromboxane and prostaglandin E2, and improve cardiovascular health by preventing fatal arrhythmias and reducing triglyceride and C-reactive protein levels.

Maternal ingestion of adequate quantities of fish (defined in many studies as at least 340 g of oily fish each week) has been associated with better childhood IQ scores, fine motor coordination, and communication and social skills, along with other benefits.

Although the FDA did not clarify which fish to eat, it specifically advised against eating fish with the highest mercury levels and implied that fish with high levels of EPA and DHA and low levels of mercury are ideal. The FDA draft did not recommend taking omega 3 fatty acid or fish oil supplements instead of eating fish, which is advice that may reflect the fact that randomized controlled trials of DHA and EPA or fish oil supplementation generally have been disappointing and that the ideal daily dose of DHA and EPA is unknown.

It seems safe to conclude that pregnant and nursing women should be advised to eat fish to benefit from naturally occurring omega 3 fatty acids, to avoid fish with high levels of mercury and other contaminants, and, if possible, to choose fish with high levels of EPA and DHA.