Comparison of seafood intake estimates and biomarkers for assessing impact on child cognition and behavior

Neurodevelopmental benefits of seafood consumption are inconclusive. In a Swedish mother-child cohort, seafood intake was assessed by food frequency questionnaires at gestational week (GW)34 and four years and by seafood biomarkers (methylmercury, arsenobetaine, long-chain polyunsaturated omega-3 fatty acids [n-3 LCPUFAs]) at GW29, birth, and four years. Maternal and child seafood intake (median: 184 and 138 g/week, respectively) was not associated with cognitive abilities (Wechsler Preschool and Primary Scale of Intelligence - Fourth Edition, WPSI-IV) or behavioral problems (Child Behavior Checklist, CBCL and Social Responsiveness Scale, Second Edition, SRS-2) at four years. However, maternal urinary arsenobetaine and erythrocyte arsenic, strongly correlated to each other, were associated with verbal abilities (B [95% CI] 0.5 [-0.0, 1.1] and 1.0 [-0.0, 2.0], per exposure doubling, respectively), as was children's erythrocyte arsenic (full-scale IQ: 1.4 [0.3, 2.5], verbal: 1.9 [0.5, 3.4]), and maternal and child erythrocyte mercury (verbal comprehension: 1.0 [-0.2, 2.2] and 1.0 [-0.3, 2.4], respectively). Maternal erythrocyte DHA and total n-3 LCPUFAs showed non-linear associations with verbal abilities (4.4 [1.0, 7.9] per IQR [1.73%, >4.2%] and 1.3 [0.1, 2.6] per 1% [>6.0%], respectively). Gestational erythrocyte and particularly newborn mercury were associated with less behavioral problems (total CBCL: B [95% CI] -0.5 [-1.3, 0.2] and -1.0 [-1.6, -0.4], per exposure doubling, respectively). In conclusion, seafood biomarkers, predominantly arsenobetaine and n-3 LCPUFAs, but not reported intake, confirmed neurodevelopmental benefits of seafood consumption in a population with below-recommended intake levels.