Fish consumption during pregnancy is a topic that has long puzzled expectant mothers and health experts alike. On one hand, fish are rich in nutrients essential for brain development, including polyunsaturated fatty acids, selenium, iodine, and vitamin D. On the other hand, fish contain methyl mercury, a known neurotoxicant. Balancing these factors can be challenging.
A recent study published in the American Journal of Epidemiology sheds light on this complex issue. Researchers analysed data from a coastal community in Massachusetts to create a new framework for understanding the risks and benefits of fish consumption during pregnancy.
The Alternative Modelling Approach
The study’s authors, including Sally Thurston, PhD, from the University of Rochester Medical Center, propose an alternative modelling approach. Instead of lumping all fish consumption together, they separated mercury exposure into fish intake and average mercury content of the consumed fish. This allowed for a more precise assessment.
The New Bedford Cohort
The research drew from the New Bedford Cohort, which assessed the health of children born to mothers residing near the New Bedford Harbour Superfund site. Hair samples collected from mothers after birth provided data on mercury exposure during the third trimester. However, this method alone couldn’t distinguish between low-mercury and high-mercury fish consumption.
A More Detailed Method
To address this limitation, the researchers estimated mercury exposure per serving of fish. Mothers completed food questionnaires, reporting the type and frequency of fish and shellfish consumed during pregnancy. By combining this information with average mercury levels by fish type, they created a detailed model to assess the impact on neurodevelopment.
Findings and Implications
The study revealed that consuming low mercury-containing fish was beneficial for neurodevelopment, while fish with higher mercury levels had detrimental effects. The authors emphasise the need to consider both mercury content and nutritional benefits when advising pregnant women on fish consumption.
Future work will apply this model to other large studies, providing clearer guidance for expectant mothers. The Seychelles Child Development Study is among those being explored.
