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Women who eat fish regularly during pregnancy give their unborn children a dramatic intellectual advantage, scientists have discovered.
Research based on more than 300 children tested at the age of 3 shows that those whose mothers ate fish more than twice a week during the second trimester performed better in intelligence tests.
"Maternal fish intake more than twice a week was associated with improved performance on tests of language and motor skills. Dietary recommendations for pregnant women should incorporate the nutritional benefits as well as the risks of fish intake," said the Harvard University researchers.
"In the present study, women who ate more than two weekly servings of tuna had children who performed better on the developmental tests," Professor Emily Oken said.
But the effects may hinge on the type of fish, because the research also shows that the children of women with the highest levels of mercury, a heavy metal found in trace amounts in some fish, scored poorly.
While mothers-to-be might feel safer eating white fish such as cod and haddock, as they tend to have lower mercury levels, these also have lower levels of fatty acids. Small fatty fish such as sardines and canned light tuna tend to contain relatively more fatty acids with less mercury, whereas dark meat fish, such as swordfish and mackerel, while offering more fatty acids, also tend to contain more mercury.
In the study, the researchers monitored 341 mothers and their children.
The children completed two tests designed to assess various aspects of intelligence. The results show that higher fish intake was associated with better child test performance, but higher mercury levels with poorer scores.
The researchers, who have carried out a second study with similar results on babies, said it may be that omega-3 fatty acids, which are linked to neurological development and which are abundant in fish, especially oily fish, are responsible for the improved performances.
The Food Standards Agency recommends pregnant women avoid eating shark, swordfish and marlin and limit the amount of tuna to two steaks or four mid-size cans a week because of the levels of mercury. It also recommends two portions of oily fish a week.
- INDEPENDENT
