Higher IQ, Better Sleep For Kids Who Eat Fish

According to a new study from University of Pennsylvania, children who consume 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.

Previous studies have revealed 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 researchers had not connected all three before.

The findings show sleep is a possible mediating pathway, the potential missing link between fish and intelligence.

Emerging Research Area

Jianghong Liu, associate professor of nursing and public health at the University of Pennsylvania and lead author of the study, said:

“This area of research is not well-developed. It’s emerging. Here we look at omega-3s coming from our food instead of from supplements.”

A group of 541 9 to 11-year-olds in China, of which 54 percent were boys and the rest girls, completed a questionnaire about how often they ate fish in the past month, with options ranging from “never” to “at least once per week.”

Children 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.

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, as well as the number of children in the home.

Fewer Sleep Disturbances

The findings show that children who reported eating fish weekly scored 4.8 points higher on the IQ exams than those who said they “seldom” or “never” consumed fish. Those whose meals sometimes included fish scored 3.3 points higher.

Further, increased fish consumption was linked to 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. We have found that omega-3 supplements reduce antisocial behavior, so it’s not too surprising that fish is behind this,”

said Adrian Raine, a professor with appointments in the School of Arts and Sciences and the Perelman School of Medicine.

Total and mediated effect of fish consumption on IQ

Total and mediated effect of fish consumption on IQ scores.
Note: All multivariable models adjusted for gender, father’s education, mother’s education, siblings, home location, and breakfast consumption habits.
Reference group: never or seldom (fish consumption).
Acronym: O, often; S, sometimes; N/S, never or seldom; β, estimated regression coefficient; SE, standard error; TSD, total sleep disturbance.
Credit: Jianghong Liu, et al. CC-BY

There are strong potential for the implications of this research, said Jennifer Pinto-Martin, professor of nursing and of epidemiology and also executive director of the Center for Public Health Initiatives:

“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. 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. Developing a taste for fish early makes it more palatable.

Fish Once A Week

Given the young age of the study group, researchers decided not to analyze the details participants reported about the types of fish consumed, though they plan to do so for work on an older cohort in the future. They 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, researchers recommend incrementally incorporating additional fish into a diet; consumption even once a week moves a family into the “high” fish-eating group as defined in the study.

“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 research was supported by National Institutes of Health/National Institute of Environmental Health Sciences grants and the Intramural program of the National Institute on Alcohol Abuse and Alcoholism.

Jianghong Liu, Ying Cui, Linda Li, Lezhou Wu, Alexandra Hanlon, Jennifer Pinto-Martin, Adrian Raine & Joseph R. Hibbeln
The mediating role of sleep in the fish consumption – cognitive functioning relationship: a cohort study
Scientific Reports 7, Article number: 17961 (2017) doi:10.1038/s41598-017-17520-w