Total mercury exposure in early pregnancy has no adverse association with scholastic ability of the offspring particularly if the mother eats fish

FAB RESEARCH COMMENT:

This study confirms and extends earlier findings, showing that provided mothers eat fish and seafood, their total mercury levels during pregnancy are NOT linked with any harmful effects on their children's cognitive development.

Children's cognitive development was assessed here via many different measures of academic achievement recorded during their childhood - using comprehensive data from the UK birth cohort study 'ALSPAC' - The Avon Longitudinal Study of Parents and Children, which allowed the researchers to control for numerous other variables that could affect these outcomes.

These data support those from earlier studies, which found that

(1) the more fish and seafod mothers ate during pregnancy, the better was their children's development on a wide range of neurodevelopmental outcomes, including motor skills, social skills, and verbal IQ. See:

• Hibbeln et Al. 2007 - Maternal Seafood Consumption In Pregnancy And Neurodevelopmental Outcomes In Childhood

(2) higher maternal mercury levels in pregnancy were in fact associated with higher verbal IQ in their children - provided that the mother ate fish and seafood. 

Fish and seafood provides key brain nutrients essential to brain development but found in few other foods, including the long-chain omega-3 DHA, iodine, selenium and Vitamin D - as well as being an excellent source of zinc, B vitamins and high-quality protein.  These nutrients (particularly selenium) help the body to deal with toxins like methyl mercury. See:

• Golding et al 2017 - Maternal prenatal blood mercury is not adversely associated with offspring IQ at 8 years provided the mother eats fish: A British prebirth cohort study

These new data clearly show that mothers' mercury levels during pregnancy did not adversely affect the academic achievement of their children - procided that they ate fish and seafood.  

Since 2014, both the US FDA and the European Food Standards agency have recommended that women should aim to consume at least 2 portions of fish a week during their pregnancy - and that up to 4 portions per week is better for children's brain health than eating none.  However, fish and seafood intakes of pregnant women in most developed countries (and many developing ones) still fall far short of this target.

• EFSA - Scientific Opinion on health benefits of seafood (fish and shellfish) consumption in relation to health risks associated with exposure to methylmercury

• 10 June 2014 - FDA - Fish: What Pregnant Women and Parents Should Know

For more information on this subject, see the following list of articles, which is regularly updated:

• Fish and Seafood in Pregnancy and Early Life