BETHESDA, MARYLAND. In 2004 the U.S. government issued guidelines regarding fish consumption for pregnant women. The advice was to limit the consumption of seafood to 340 g per week, the objective being to limit the intake of neurotoxins that might adversely affect the fetus. But optimum fetal neurodevelopment depends on specific nutrients derived from dietary sources and the essential omega-3 fatty acid docosahexaenoic acid (DHA) is not only one of the most critical, but seafood is the major source. A study has just appeared in the journal Lancet, which examines an important question, i.e. is the limitation of seafood intake to less than 340 g/week during pregnancy potentially detrimental to fetal neurodevelopment? In this study, Hibbein et al report on the results of follow-up study based in Bristol, UK. Over 14,500 pregnancies were involved and 13,988 children survived for at least 12 months. Questionnaires were used during pregnancy and the children were followed for 6 months to 8 years. The object was to assess developmental, behavioral and cognitive outcomes as they related to the level of fish consumption during pregnancy. About 85% of the eligible expectant mothers participated. Questionnaires were used periodically to determine development and behavioral characteristics; the intelligence quotient (IQ) at age 8 was determined for 5449 children.
After adjustments for confounding, maternal seafood intake during pregnancy of less than 340 g/week was associated with increased risk of the children in question being in the lowest fifth for verbal IQ and in addition there was a significant trend to greater risk as the seafood consumption declined to zero. Low maternal seafood intake was also associated with increased risk of suboptimal outcomes for development in the areas of social behavior, as well as motor, communication and social development, and for each outcome the lower the fish intake the higher the risk for suboptimal development. The authors conclude that maternal fish consumption of less than 340 g/week did not protect children from adverse neural development, and that in fact intake exceeding 340 g/week (12 oz or 3/4 lb) resulted in beneficial effects on child development. Thus the authors conclude that following the guidelines could actually be detrimental, and that the results suggest that the benefits from eating more than 340 g of seafood per week outweighed the risk of harm from exposure to trace contaminants.
Hibbein, J. R. et al. Maternal Seafood Consumption in Pregnancy and Neurodevelopmental Outcomes in Childhood (ALSPAS study): An Observational Cohort Study. Lancet, 2007, Vol. 369, Feb 17, pp. 579-84.