Want smarter kids who sleep through the night? Feed them fish, a new study says

A new University of Pennsylvania School of Nursing study found that children who ate fish regularly scored nearly five points higher on a standard IQ test that measures cognitive function in children. The kids who favored fish over traditionally kid-friendly items like, say, chicken fingers and fries, also slept better and had fewer sleep interruptions.

The study of 541 boys and girls in China, ages 9 to 11, who completed a questionnaire about how often they consumed fish in the past month, was published Dec. 21 in Scientific Reports.

The results found that those who said they ate fish once a week scored 4.8 points higher on the Wechsler Intelligence Scale IQ test than those who seldom or never included fish in their diets.

“This area of research is not well-developed. It’s emerging,” said Jianghong Liu, the lead author on the paper and an associate professor of nursing and public health, told the school’s Penn News. “Here we look at omega-3s coming from our food instead of from supplements.”

Even these children who ate fish only occasionally benefited with better verbal and non-verbal skills and scored an average of 3.3 IQ points higher than those who turned their noses up at fish. The link between omega-3 fatty acids that are found in fish – but not all kinds of fish – and better brain function has been found in many studies over the years.

That’s good news in South Florida, which certainly doesn’t lack for fish options.

However, Sheah Rarback, a registered dietitian on the faculty of the University of Miami Miller School of Medicine, questions the Pennsylvania study’s conclusions. She said the study of these kids who kept a food diary and took an IQ test should not be considered cause and effect – as in an eat-fish-and-you’ll-be-smarter certainty.

“You have to be careful to say ‘eating fish will cause better intelligence.’ It’s an association. There could be other things factoring in there so it’s not cause and effect,” Rarback said.

“That said, fish is a good, nutritious, lean protein for kids and adults,” Rarback said. “They are probably zeroing in on the omega-3 fatty acids. There are fish that have higher amounts and, of these, is a fish kids love – tuna. Tuna is a great source of lean protein.”

The study’s results didn’t surprise Rarback, though. “This is not surprising because omega-3 fatty acids are concentrated in the brain and play a role in brain neurological function. So I would say this is an interesting study. But it’s association, not cause and effect.”

Other fish that are high in the beneficial omega-3 fatty acids are salmon and sardines. Since most kids like tuna, that’s an easy dish to serve in sandwiches, salads or by itself. Salmon burgers could also be a healthy and enticing option for kids.

“Fish oils are also very good anti-inflammatories and so many root causes of disease are inflammation. So you can’t lose by eating more fish. But what I say is important, particularly with kids with developing brains, is to go for lower mercury fish,” Rarback cautions.

Mercury, a metallic element found in the air and released by coal-fired power plants and other industries, can build up in the human body over years and cause neurological problems, including memory loss and personality disorders, according to the Food and Drug Administration. The FDA warns that children, pregnant women and women who plan to become pregnant are at the greatest risk because mercury can damage the nervous system of a developing child.

Fish highest in mercury are large predators like largemouth bass and sharks, since they ingest all the mercury from the fish they consume.

“Fish with the lowest potential for mercury is canned white tuna and salmon – those are two good choices for kids. And sardines, though I’ve yet to meet the kid who likes sardines,” Rarback said, laughing. “But sardines have the lowest potential for any types of toxins because they are so small, so they are terrific.”

Professor Jennifer Pinto-Martinone, executive director of Penn’s Center for Public Health Initiatives, told Penn News the research “adds to the growing body of evidence showing that fish consumption has really positive health benefits and should be something more heavily advertised and promoted. Children should be introduced to it early on.”