Higher maternal seafood consumption during pregnancy results in children showing better neurological function than children whose mothers eat low amounts or no seafood during pregnancy, according to an article published in this week's issue of The Lancet.
Seafood is the predominant source of omega-3 fatty acids, which are essential for optimum fetal brain development. However, in the USA, women are advised to limit their seafood intake during pregnancy to 340 g per week, to avoid fetal exposure to trace contaminants of neurotoxins*.
Joseph Hibbeln (National Institutes of Health, Bethesda, USA) and colleagues from Bristol University, analysed an observational cohort study, the Avon Longitudinal Study of Parents and Children (ALSPAC)**, to assess the possible benefits and hazards to a child's development of different levels of maternal seafood intake during pregnancy. Maternal seafood intake during pregnancy of less than 340 g (ie, less than three portions) per week was to found to be associated with increased risk of their children being in the lowest quartile of verbal IQ, compared with mothers who consumed more than 340 g per week. Furthermore, low maternal seafood intake was associated with increased risk of suboptimum outcomes for prosocial behaviour, fine motor, communication, and social development scores***. For each outcome measure, the lower the intake of seafood during pregnancy, the higher the risk of suboptimum developmental outcome.
The authors conclude: "We recorded no evidence to lend support to the warnings of the US advisory that pregnant women should limit their seafood consumption. In contrast, we noted that children of mothers who ate small amounts (<340 g per week) of seafood were more likely to have suboptimum neurodevelopmental outcomes than children of mothers who ate more seafood than the recommended amounts."
In an accompanying Comment, Gary Myers and Philip Davidson (University of Rochester Medical Center, New York, USA) state: "Epidemiological findings have presented a dilemma for regulatory authorities around the world. Should fish consumption be restricted to lower methylmercury exposure? Or should it be encouraged for the nutrients essential to neurodevelopment?…People are perhaps best served by advisories that follow science and are conservative in the absence of compelling scientific evidence of harm."
Dr Joseph Hibbeln, National Institutes of Health, Bethesda, USA. T) +1 301 435 4028 jhibbeln@mail.nih.gov
Professor Jean Golding, University of Bristol, UK. T) +44 (0)117 331 7925 jean.golding@bristol.ac.uk
Comment Dr Gary Myers, University of Rochester Medical Center, New York, USA. gary_myers@urmc.rochester.edu
Notes to Editors
*The 2004 US advisory (US Environmental Protection Agency and Department of Health and Human Services) aimed to reduce the potential harm from pollutants in seafood, specifically methylmercury, which can have harmful effects on the developing brain.
**ALSPAC (www.alspac.bris.ac.uk)—was designed to assess the environmental factors (including diet) during and after pregnancy that might affect the development, health, or wellbeing of the child. All pregnant women living in Bristol, UK, with an expected delivery date between April 1, 1991 and December 31, 1992, were eligible for inclusion. Mothers were sent postal questionnaires four times during pregnancy and then at specific time points after birth of the child to obtain information about diet, education, social circumstances, and behavioural and developmental outcomes. Children had their intelligence quotient (IQ) measured by the Weschler Intelligence Scale for Children III at age 8 years.
***Adverse outcomes associated with insufficient intakes of long chain omega-3 fatty acids during pregnancy in other studies include: intrauterine growth retardation, delayed or suboptimum depth perception, adverse neurodevelopmental measures, residual deficits in fine motor skills, speed of information processing in infants, and irreversible deficits in serotonin and dopamine release.
Journal
The Lancet