“Advice that limits seafood consumption might reduce the intake of nutrients necessary for optimal neurological development.”
12% of women reported eating no fish or seafood during pregnancy; 65% consumed up to 12 ounces (340 g) of fish per week; 23% consumed more than 12 ounces of fish per week.
Higher seafood consumption during pregnancy was associated with lower risk of suboptimal verbal IQ.
In every outcome measured, the lower the seafood consumption by the mother during pregnancy, the greater the risk of suboptimal development in the child.
EPA and DHA Omega-3 intake during pregnancy and developmental outcomes in children
Hibbeln JR, Davis JM, et al. Maternal seafood consumption in pregnancy and neurodevelopmental outcomes in childhood (ALSPAC study): An observational cohort study. Lancet, 2007;369:578-585.
In 2004, the United States Food and Drug Administration (FDA) and US Environmental Protection Agency (EPA) published advice for pregnant and nursing women and young children . They were advised to 1) avoid eating shark, swordfish, king mackerel and tilefish and 2) eat up to (and not more than) 12 ounces a week of a variety of fish and shellfish that are low in mercury (e.g., tuna, salmon, shrimp). However, fish consumption among pregnant women has been shown to decline following national advisories .
The Avon Longitudinal Study of Parents and Children (ALSPAC) was designed to assess environmental factors, including diet, during and after pregnancy that may affect the development, health, or well-being of the child. Nearly 12,000 pregnant women living in Bristol, UK and surrounding areas participated in the study. These women were expected to give birth between April 1, 1991 and December 31, 1992.
This carefully controlled study gathered information on the mothers’ diets during pregnancy and compared developmental, behavioral, and cognitive outcomes in the children from 6 months to 8 years of age. A remarkable 28 potential confounding variables were controlled, including family adversity, education, ethnicity, housing, partner in the home, alcohol and tobacco use, and 12 food groups in addition to fish.
Information about the mothers’ intake of fish and seafood consumption during pregnancy was gathered using a validated Food Frequency Questionnaire at 32 weeks gestation. Questions about frequency of consumption of white fish (e.g., cod, haddock, etc.), dark or oily fish (e.g., tuna, sardines, etc.), and shellfish (e.g., prawns, crab, etc.) were asked. Women could choose between 5 consumption categories: never or rarely; once in 2 weeks; 1-3 times per week; 4-7 times or week; or more than once a day. Omega-3 fatty acid intake was assessed using typical nutrient profiles of British seafood products.
Assessment of Children
The children’s developmental, behavioral, and cognitive progress was assessed from the age of 6 months to 8 years at regular, pre-determined age intervals. Mothers completed structured questionnaires about their children’s development and behavior (e.g., communication, gross, fine motor and social skills) in their homes. The Griffiths scale was administered to a representative subpopulation (n=1045) by trained psychologists. Intelligence Quotient (IQ) was estimated using an abbreviated version of the Wechsler Intelligence Scale for Children (WISC-IIIUK) when the children were 8 years of age.
The pregnant women consumed from zero to 3,268 grams (g) of fish per week; mean 235 g per week (approximately 8.4 ounces).
Estimated intake of EPA and DHA omega-3 from seafood ranged from zero to 15.6 g per week; mean 1.06 g per week.
Low seafood consumption was more common in homes with social and economic disadvantage, in smokers, and those who did not breastfeed.
1.7% of women consumed fish oil supplements during pregnancy (in 1991 and 1992). The outcomes in the children of mothers who consumed supplements, but did not eat fish, were similar to those of mothers who did eat fish.
No statistical trends toward benefit (in any of the measured variables in the children) were associated with a dietary intake of less than 340 g (about 12 ounces) of seafood per week.
Compared to the children whose mothers consumed more than 340 grams (more than 12 ounces) of fish per week during pregnancy, the children of the women who consumed less than 340 grams (less than 12 ounces) of fish per week during pregnancy were associated with an increased risk of being in the lowest quartile of verbal IQ.
Higher risk of suboptimal development of social development, communication, and fine motor skills was also associated with low seafood intake
These data, collected over an 8-year period, from nearly 12,000 pregnant women and their children suggest beneficial effects on child development when maternal intake of fish and seafood is greater than 340 grams (> 12 ounces) per week. These findings suggest that following the US FDA and US EPA advisory to limit fish and seafood intake during pregnancy may result in suboptimal neural development in children; risk from the absence of nutrients may be greater than risk of harm from potential exposure to mercury.
Vannice GK, Byelashov A, Rice, B. Advances in EPA & DHA Research: EPA and DHA Omega-3 intake during pregnancy and developmental outcomes in children. Quarterly Journal of Significant Omega-3 Research, 03;(03), 2010.
1. http://www.epa.gov/waterscience/fish/files/MethylmercuryBrochure.pdf. accessed January 12, 2011.
Oken E, Kleinman KP, et al. Decline in fish consumption among pregnant women after a national mercury advisory. Obstet Gynecol,