Mothers-to-be who eat seafood daily less likely to have children with attention deficit disorder
Scientists also uncovered rates of Attention Deficit Hyperactive Disorder (ADHD) were lower among children whose mothers consumed plenty of seafood in pregnancy.
Researchers based at the Barcelona Institute for Global Health looked at the diets of hundreds of mothers and their children.
Their research flies in the face of British Health Service (NHS) advice, which says mothers-to-be should not eat more than two portions of oily fish a week because it can be toxic.
The findings were published in the International Journal of Epidemiology.
Results showed eight-year-olds of mothers who consumed four portions each week scored 16 per cent better on tests of their attention span.
Youngsters whose mothers ate a portion of fish every day scored 24 per cent better, compared to those whose mother just had one portion each week.
Their risk of ADHD, which can cause hyperactive behaviour and is not always to blame for poor attention spans, was also slashed by up to 16 per cent.
Oily fish, such as salmon and mackerel, are the most beneficial because they are rich in omega-3 fatty acids, which aid brain structures in the womb, researchers said.
Consumption of various types of seafood was investigated by the research team, who looked at 1,641 mother/child pairs.
The mothers completed numerous questionnaires about what foods they ate from a list of more than 100 items and how often. One serving of fish was measured as 115 grams, which is roughly the weight of one fillet of salmon.
Data on the dietary habits of children were collected using the same questionnaire at one, five and eight years of age. Parents reported symptoms of ADHD using the Revised Conners’ Parent Rating Scale Short Form when their child was eight years of age.
It was at this age the children also completed the Attention Network Task (ANT), a computer-based test. It measures aspects of attention – in this study, error, and speed – by requiring the child to press keys in response to an action on the screen.
Results showed the apparent attention-boosting effects were only found in children whose mothers consumed at least four servings a week.
Scores were higher in children whose mothers preferred fatty fish, such as salmon and mackerel, or lean fish, such as cod or haddock, compared to mothers who relied on canned tuna or shellfish.
Dr. Jordi Júlvez, the lead author of the study, said the consumption of seafood during the first trimester of pregnancy had a greater effect on attention capacity. Little effect was noted among children who consumed seafood regularly aged five, or for mothers who consumed lots of oily fish later in pregnancy.
This, he claims, is because brain development during the early stages of pregnancy is more crucial.
The researchers also found genetic variations affect how well children can process fatty acids, and hence develop healthy attention spans.
Júlvez said: “Children with, for example, the rs1260326 CC genotype – which has been associated with lower PUFA levels – had worse attention scores if their mothers had not eaten much seafood during pregnancy. But their outcomes improved if their mothers consumed more seafood.”
The team insists on the need for more research on this subject to determine exactly which species of fish and what quantities may be beneficial to foetal development.