12 January - 20 June 2016

Does eating fish regularly improve IQ and sleep in children?

Scientists have found that children who consume fish at least once a week sleep better and have higher IQ scores than those who consume fish less frequently or not at all.

Scientists have found that children who consume  fish at least once a week sleep better and have higher IQ scores than those who consume fish less frequently or not at all. The team, from the University of Pennsylvania, discuss how previous studies have found that consumption of long chain omega 3 fatty acids, EPA and DHA, found in fish, have been associated with improved cognitive outcomes.  However they note that knowledge on “how they improve cognitive performance remains limited.”  

They suggest that lack of sleep has been associated with poor school performance, learning and memory.  Liu et al. note in Scientific Reports  that animal studies have indicated that sleep is affected by omega-3 fatty acids, as DHA has been linked to regulation of melatonin production and essential fatty acids involved with the production of prostaglandins, a “potent endogenous sleep-promotion substance.”

In this current study, Liu et al. aimed to investigate dietary fish intake, sleep quality and cognitive outcomes in 541 9-11 year old, healthy, Chinese schoolchildren.  Using a self-administered food frequency questionnaire, the children reported on their fish consumption over the last month measured as never, seldom (less than 2 times per month), sometimes (2-3 times per month)  and often (at least once per week).  Liu et al. combined never and seldom into one group, so that the 3 levels investigated were “often”, “sometimes”, and “never or seldom”.  The children’s parents completed a Children’s Sleep Habits Questionnaire which asked questions on 33 sleep-disturbance items.  IQ was measured at age 12 and was assessed using the Chinese version of the Wechsler Intelligence Scale for Children-Revised which consists of six verbal subtests, and six non-verbal subtests.  The team also collected sociodemographic information at baseline, including breast feeding duration, and breakfast consumption. 

Of the 541 children, 137 reported consuming fish often, 315 sometimes, and 89 never or seldom.  They state “IQ measures and the total sleep disturbances score demonstrated a significant association with fish consumption: as compared to children who never or seldom ate fish, those having more frequent fish intake had higher verbal and full scale IQ scores as well as a lower total sleep disturbance score.”  Those in the more frequent fish intake group scored 4.75 point higher in verbal IQ, 3.79 points higher in performance IQ and 4.80 points higher in full scale IQ, compared to those in the seldom group. The authors also report that breakfast consumption habits were also significantly associated with verbal and full scale IQ.  Eating fish was also associated with less sleep disturbances.  Those having less sleep disturbances were more likely to have higher IQ functioning.  However after using mediation analysis, Liu et al. note that “adjustments for total sleep disturbances score did not affect the association between fish consumption and performance IQ, suggesting overall sleep quality was not a mediator.”

The authors note in a press release that future work will investigate the types of fish consumed, in an older cohort. They also want to add to this current observational study to establish, through randomised controlled trials, if eating fish can lead to better sleep, better school performance and other real-life, practical outcomes.

RSSL's Lipids Laboratory, part of the Investigative Analysis Team has expertise in all aspects of fat analysis and fatty acid profiling, including the determination of omega-3 and omega-6 fatty acids. To find out more please contact Customer Services telephone 0118 918 4076 or e-mail enquiries@rssl.com

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