Blood Markers of Seafood Intake Linked to Better Child Verbal Skills and Behavior

This Swedish study followed mothers and their children to see whether eating seafood during pregnancy and early childhood was linked to how kids scored on tests of thinking skills and behavior at age four. Researchers compared two ways of measuring seafood intake: questionnaires where parents reported what they ate, and biological markers measured directly in blood and urine (like mercury, arsenic compounds, and omega-3 fatty acids).

Surprisingly, the self-reported seafood intake from questionnaires showed no connection to children’s cognitive scores or behavioral problems. However, the biological markers told a different story. Higher levels of certain arsenic compounds (arsenobetaine, which comes specifically from seafood) and mercury in blood were associated with better verbal ability scores in children. Levels of DHA and total omega-3 fatty acids in mothers’ blood also showed links to improved verbal skills. Additionally, higher mercury levels in cord blood at birth were associated with fewer reported behavioral problems in children.

The researchers concluded that biological markers, rather than questionnaire-based estimates, better captured the relationship between seafood consumption and children’s neurodevelopment—especially in this population where seafood intake was generally below recommended levels.