No risk from mercury in seafood diet - study
confirms earlier findings that there is no detectable risk between
mercury in seafood and impaired neurodevelopment in young children.
Good news for pregnant mothers with a craving for fish.
Food safety agencies in a number of countries, including the UK and the US, have frequently warned pregnant mothers about eating certain types of seafood because of the supposed risk of mercury in the fish affecting the development of their unborn child.
But the latest research, published in this week's issue of The Lancet appears to show that these fears are unfounded, confirming earlier findings from the Seychelles - where fish consumption is the main component of the local diet - which also showed a seafood diet is not associated with impaired neurodevelopment in young children.
The latest findings come from a research team from the University of Rochester in the US who, along with colleagues from the Seychelles investigated 779 mother-infant pairs enrolled in the Seychelles Childhood Development Study, established in 1989/1990. The mothers reported high fish consumption - 12 meals a week compared with one meal a week on average in the US.
According to the researchers, the fish in Seychelles contained similar concentrations of methyl mercury as commercial ocean fish elsewhere, and the prenatal MeHg exposure was determined from maternal hair growing during pregnancy.
The investigators assessed neurocognitive, language, memory, motor, perceptual-motor and behavioural functions in children at nine years of age. Out of 21 endpoints, only two tests were associated with prenatal methyl mercury exposure: decreased performance in a motor test (the grooved pegboard using the non-dominant hand in males), and improved scores in the hyperactivity index of the Conner's teacher rating scale.
The investigators commented, however, that these two results probably arose by chance, and concluded that there was no evidence of neurodevelopmental risk from prenatal methyl mercury exposure resulting solely from ocean fish consumption.
In an accompanying commentary, Constantine Lyketsos from Johns Hopkins Hospital in the US concluded: "On balance, the existing evidence suggests that methyl mercury exposure from fish consumption during pregnancy, of the level seen in most parts of the world, does not have measurable cognitive or behavioural effects in later childhood. For now, there is no reason for pregnant women to reduce fish consumption below current levels, which are probably safe."
