World Bulletin / News Desk
Children's risk of developing attention-deficit/hyperactivity disorder (ADHD) later in life may be tied to how much fish their mothers ate while pregnant, according to a U.S. study.
Researchers writing in the Archives of Pediatrics & Adolescent Medicine found that eating at least two servings of fish per week was linked to about a 60 percent lower risk of kids developing certain ADHD-like symptoms.
But elevated mercury levels, which can also come from eating more fish - depending on the fish - were tied to a higher risk of developing the symptoms, such as hyperactivity, impulsiveness and inattentiveness.
Though the study did not prove cause and effect, and did not use a formal diagnosis of ADHD, it may offer insights into a condition that's estimated to have an impact on one in 10 children in the United States, researchers say.
"The really important message is to eat fish," said Sharon Sagiv, the study's lead author from the Boston University School of Public Health.
"Just stay away from mercury-containing fish, because these protective effects are pretty important."
Sagiv said it's best to stay away from "big fishes," such as tuna and swordfish, which typically contain the most mercury. Instead, stick to fishes such as haddock and salmon.
Past studies looking at the link between mercury and ADHD have produced conflicting results.
For the new study, the researchers followed 788 children who were born near New Bedford, Massachusetts, between 1993 and 1998. They used hair samples taken from the mothers right after delivery to test their mercury levels, and food diaries to see how much fish they ate.
Then, once the children were about 8 years old, the researchers asked their teachers to evaluate the kids' behaviors to see how many exhibited ADHD-like symptoms.
After taking all of the information into account, the researchers found 1 microgram of mercury per gram of a mother's hair - about eight times the average levels found in similar women's hair in another analysis - was tied to about a 60 percent increase in the risk of their child exhibiting ADHD-like behaviors.
But there was no link below 1 microgram of mercury per gram of a mother's hair.
Sagiv added that the negative effects from lower levels of mercury may be canceled out by the benefits from eating fish. The children appeared to be 60 percent less likely to exhibit impulsive or hyperactive behaviors if their mothers ate two or more servings of fish per week.
That finding conflicts with the U.S. government's recommendation that says pregnant women should eat no more than two six-ounce servings of fish per week to limit their exposure to mercury.
"I think it does call into question those guidelines, but this is only one study and the results should be confirmed," Sagiv told Reuters health.
In an editorial that appeared with the study, Bruce Lanphear at Simon Fraser University in Vancouver, echoed Sagiv's advice on avoiding "big fishes."
In the long term, we have to really find ways to fight contamination levels in fish so years from now we don't have to give this advice," he added.
Some of the world's major cities, most Pacific island nations are at risk of disappearing due to rising seas
Yemen forces allied to the Houthi have launched a scud missile toward southern Saudi Arabia
Three dozens of fires may cause an ecological catastrophe to Lake Baikal in Russia
National and international slow responses to epidemies show how far the world is from achieving global health security
Call for action in madrassas and mosques around the world is intended to emphasize the role Islam can play in combating climate change
New reports claim parent company Alphabet is attempting to fight malaria and other diseases transmitted via insects
Scientists are predicting that Earth could be heading towards an extraordinary event which would see compasses point south and the sun rise in the West.
Ambitious document to be ratified next month during General Assembly meeting
Using alternative sources to firewood as opened the path for one Kenyan factory to reduce energy costs and save the environment
A vaccine developed by researchers has shown promising results with a trial tests showing 100% protection against Ebola
Low lying areas in the Sundarbans region has forced many mothers to join fathers away from home to work, leaving little choice for their children but to take refuge in hostels away from family.
World Wildlife Fund communications manager says plan could come to fruition by 2020, but depends on final gov’t approval
Meteorologists expect El Nino effects to delay the rainy season as dry conditions force locals to pray for rain
Hawaii has become the first American state to ban the use of plastic bags.
Gene therapy for cystic fibrosis has for the first time shown slight but significant benefit on lung function, new British research reveals.