Restrictions on the amount of fish pregnant women should eat may need to be re-evaluated.
For a new study, a group of Spanish scientists conducted a study of nearly 2,000 pairs of mothers and children from the Spanish Childhood Environment Project population study to determine whether seafood is beneficial for a child's neuropsychological development. Their answer? A resounding yes.
Researchers followed the pairs from the first trimester through the child's 5th birthday, finding improved brain function in children.
The women involved consumed large fatty fish, such as swordfish and albacore tuna; smaller fatty fish, such as mackerel, sardines, anchovies and salmon; and lean fish, such as hake or sole, as well as shellfish and other seafood, reports The Independent.
Women were tested for blood levels of vitamin D and iodine, which are both thought to contribute to a child's brain and cognitive function. Umbilical cord blood was tested after delivery to measure fetal exposure to mercury and polychlorinated biphenyls (PCBs), which are thought to be linked to learning deficits and developmental delays in children who are exposed to these chemicals in the womb.
The research also suggests that fears of mercury contamination may be too intense in some countries. This study found that women who ate 600 grams of fish each week while pregnant were not negatively affected by mercury and PCBs linked with the food. Past studies have found the two substances to be neurotoxic and potentially harmful to a baby's nervous system, The Independent reports.
The children were administered a Childhood Asperger Syndrome Test (CAST) at the ages of 14 months and 5 years. The research, which was published in the American Journal of Epidemiology, found that the children of pregnant women who ate more than 340 grams of seafood a week were more likely to have higher neuropsychological scores. There was also an apparent increase in children's test scores with every additional 10 grams per week, up to about 600 grams, or 21 ounces. The link between higher maternal fish consumption and increased brain development in children was apparent at the age of 5.
Lean fish and large fatty fish, specifically, showed a correlation with better test scores. And fish intake during the first trimester, in comparison with a later point during pregnancy, had the strongest associations.
The US Food and Drug Administration's 2014 guidelines suggest that women eat no more than 12 ounces of fish per week. The National Health Service for England recommends that pregnant women steer clear of shark, swordfish and marlin because they contain high levels of mercury. It also states women should limit themselves to two portions a week of salmon, trout, mackerel, herring, sardines, pilchards and fresh tuna.
"I think that in general people should follow the current recommendations," said lead study author Dr. Jordi Julvez, of the Center for Research in Environmental Epidemiology in Barcelona, in an interview with Reuters. "Nevertheless this study pointed out that maybe some of them, particularly the American ones, should be less stringent."
Future research should be carried out to better understand the effects of fish intake on pregnant women and their children, these researchers said. Talk to your doctor about any diet concerns you may have.
This study was funded by grants from the Spanish Institute of Health Carlos III and others. The authors disclosed no conflicts of interest.