Children who eat fish at least once a week sleep better and have IQ scores that are 4 points higher, on average, than those who eat fish less frequently or not at all, according to a new study.
According to researchers at the University of Pennsylvania, previous studies showed a relationship between omega-3s, the fatty acids in many types of fish, and improved intelligence, as well as omega-3s and better sleep. But they’ve never been connected before, the researchers say.
The new research conducted by Jianghong Liu, Jennifer Pinto-Martin, and Alexandra Hanlon of the School of Nursing, and Penn Integrates Knowledge Professor Adrian Raine, reveals sleep as a possible mediating pathway, the potential missing link between fish and intelligence.
“This area of research is not well-developed. It’s emerging,” said Liu, lead author on the paper and an associate professor of nursing and public health. “Here we look at omega-3s coming from our food instead of from supplements.”
For the study, the researchers recruited 541 children between the ages of 9 and 11 in China. More than half — 54 percent — were boys, while 46 percent were girls.
The children completed a questionnaire about how often they ate fish in the past month, with options ranging from “never” to “at least once per week.”
The kids also took the Chinese version of an IQ test called the Wechsler Intelligence Scale for Children-Revised, which examines verbal and non-verbal skills, such as vocabulary and coding, the researchers said.
Their parents then answered questions about sleep quality using the standardized Children Sleep Habits Questionnaire, which included topics such as sleep duration and frequency of night waking or daytime sleepiness.
Finally, the researchers controlled for demographic information, including parental education, occupation, and marital status and the number of children in the home.
Analyzing these data points, the Penn team found that children who reported eating fish weekly scored 4.8 points higher on the IQ exams than those who said they “seldom” or “never” ate fish.
Those whose meals sometimes included fish scored 3.3 points higher.
Increased fish consumption also was associated with fewer disturbances of sleep, which the researchers say indicates better overall sleep quality.
“Lack of sleep is associated with antisocial behavior; poor cognition is associated with antisocial behavior,” said Raine. “We have found that omega-3 supplements reduce antisocial behavior, so it’s not too surprising that fish is behind this.”
“It 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,” added Pinto-Martin. “Children should be introduced to it early on.”
That could be as young as 10 months, as long as the fish has no bones and has been finely chopped, but should start by around age 2, the researcher advises.
“Introducing the taste early makes it more palatable,” she said. “It really has to be a concerted effort, especially in a culture where fish is not as commonly served or smelled. Children are sensitive to smell. If they’re not used to it, they may shy away from it.”
Given the young age of the study group, the researchers chose not to analyze the details participants reported about the types of fish consumed, though they plan to do so for work on an older group in the future.
The researchers also want to add to this current observational study to establish, through randomized controlled trials, that eating fish can lead to better sleep, better school performance, and other real-life, practical outcomes.
For the moment, the researchers recommend incrementally incorporating additional fish into a diet. Eating fish just once a week moves a family into the “high” fish-eating group as defined in the study, the researchers noted.
“Doing that could be a lot easier than nudging children about going to bed,” Raine said. “If the fish improves sleep, great. If it also improves cognitive performance — like we’ve seen here — even better. It’s a double hit.”
The study was published in Scientific Reports, a Nature journal.
Source: University of Pennsylvania