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December 26, 2017

Penn study: Sleep may explain link between fish consumption, intelligence

Fish oil has long been prescribed as a supplement for mental clarity and focus, but could it be that the cognitive benefits of omega-3 fatty acids come indirectly from an improvement in sleep health?

New research from the University of Pennsylvania shows that weekly consumption of fish boosts the IQs of growing children and also appears to help reduce disturbances in their sleep. It might be that their learning ability is significantly aided by the rest and recovery they get from having fish in their diet.

While previous studies on omega-3s have separately established positive relationships with intelligence and sleep, the Penn team's study in Scientific Reports represents the first investigation connect all three using pediatric diet instead of supplements.

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

The cohort study used a questionnaire given to 541 Chinese children between the ages of nine and 11 years old, controlling for demographic factors such as parental education, occupation, marital status and number of children in the home. Fifty-four percent of the children were boys and 46 percent girls.

Children were first asked how often they eat fish, with options ranging from "never" to "at least once a week," before taking the Wechsler Intelligence Scale for Children-Revised, a Chinese test that assesses verbal and non-verbal skills, including vocabulary and coding.

Parents of the children participating in the study answered questions about sleep quality using the Children Sleep Habits Questionnaire, which covers issues such as sleep duration, frequency of night waking an daytime sleepiness.

Across all data points, researchers found that children who reported eating fish weekly scored 4.8 points higher on the IQ tests than those who said they "seldom" or "never" consumed fish. Among children who "sometimes" ate fish, IQs were 3.3 points higher.

The majority of the children who reported eating fish regularly had fewer sleep disturbances those without fish in their diets, according to their parents.

Lack of sleep is associated with antisocial behavior; poor cognition is associated with antisocial behavior," said Raine, who has appointments in the School of Arts and Sciences and Penn's Perelman School of Medicine. "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 Penn Integrates Knowledge Professor attached to the study.

Researchers believe the study results could provide parents a promising approach to improving their kids' sleep health without having to pester them about getting to bed.

Jennifer Pinto-Martin, executive director of Penn's Center for Public Health Initiatives, said parents should look to introduce their kids to fish early, between 10 months and two years old.

"Introducing the taste early makes it more palatable," Pinto-Martin 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."

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