By Meenu Johnkutty ’21

Eating fish might be more beneficial than originally thought. Researchers from the University of Pennsylvania recently published a study outlining the benefits of fish consumption on sleep quality and cognition in children. The study was originally published in Scientific Reports, a branch of Nature, with Jianghong Liu as the lead author.

Long chains of omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are essential nutrients found in fish that are linked to a multitude of cardiovascular and mental health benefits. Fatty acids are known for their role in the maintenance and growth of neural tissue, which is composed of white fat known as myelin. Fatty tissue acts like insulation around a copper wire, allowing for high speeds of information transmission throughout the nervous system.

While the effects of omega-3 fatty acids have been studied in relation to cognition, this study is the first to analyze these nutrients’ relation to sleep. The researchers hypothesized that increases in cognition may be due in part to the mediating role sleep plays in increasing IQ. In order to investigate this link, the researchers conducted a longitudinal study, investigating the effects of fish consumption in their subjects across a long period of time. 1009 Chinese school children aged nine to eleven participated in the first wave of the study, and then the number was halved to approximately 541 school children in the second wave of the study.

The subjects were asked to complete a questionnaire that collected information about food intake, including how much fish they consumed. Parents of the school-aged children completed questionnaires that asked about their children’s sleep quality. Sleep quality was measured with a “total sleep disturbance score” which used items like bedtime resistance, sleep anxiety, sleep-onset delay, and other sleep-disturbance items to form a narrative about total sleep quality. At the age of 12, the children took IQ tests that measured verbal and nonverbal intelligence. This information along with the answers provided by the questionnaires about fish intake and sleep quality were then statistically analyzed.

The results of the study revealed higher IQ scores in those children that reported higher sleep quality. In addition, those subjects that had higher sleep quality reported consuming higher quantities of fish. The researchers reported that sleep quality “partially mediated” the association between fish consumption and cognitive functioning, thus linking eating fish with higher cognitive thinking. The researchers were able to conclude that increasing fish consumption would be beneficial for improving sleep quality and boosting cognition in adolescents, thus giving us another incentive to include more fish in our diets.

References:

1. J. Liu, et al., The mediating role of fleep in the fish consumption – cognitive functioning relationship: a cohort study. Scientific Reports 7, (2017). doi: 10.1038/s41598-017-17520-w.
2. Image retrieved from: https://www.pexels.com/photo/close-up-cooking-cuisine-delicious-629093/