Want to boost your kids' IQ? Feed them fish at least once a week

Want to sharpen your kids' mental skills and boost intelligence quotient (IQ) levels? Feed them fish at least once a week, says a study.

The findings showed that children who eat fish at least once a week sleep better and have IQ scores that are four points higher, on average, than those who consume fish less frequently or not at all.

Those whose meals sometimes included fish scored 3.3 points higher. In addition, increased fish consumption was associated with fewer disturbances of sleep, which the researchers say indicates better overall sleep quality.

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 all been connected before.

The new study reveals sleep as a possible mediating pathway -- the potential missing link between fish and intelligence, the researchers said.

"Lack of sleep is associated with antisocial behaviour, poor cognition is associated with antisocial behaviour," said Adrian Raine, Professor at the University of Pennsylvania.

"We have found that omega-3 supplements reduce antisocial behaviour, so it's not too surprising that fish is behind this."

The study "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", said Jennifer Pinto-Martin, Professor at the varsity.

For the study, published in the journal Scientific Reports, a cohort of 541 nine to 11-year-olds in China -- 54 per cent boys and 46 per cent girls -- completed a questionnaire about how often they consumed fish in the past month.

Their parents then answered questions about sleep quality, which included topics such as sleep duration and frequency of night waking or daytime sleepiness.