Seafood, which is rich in omega-3 fatty acids such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), is reported to be associated with sleep. Animal studies have suggested that these fatty acids influence circadian clock system. People can be classified into morning, intermediate, and evening types based on their chronotype. Social jetlag, defined as the discrepancy in sleep schedule between workdays and free days, is more pronounced in individuals with an evening chronotype. However, the association between the timing of seafood and EPA and or DHA consumption and sleep phase in humans remains unclear. This cross-sectional study aimed to examine the relationship between seafood, EPA, and DHA intake at three different mealtimes and from snacks and sleep patterns among Japanese adults. Dietary and sleep data were collected from 5,975 adults aged 18-75. Generalized estimating equations were used to assess the associations between sleep patterns and seafood, EPA, and DHA intake at breakfast, lunch, dinner, and snack times-measured using a mobile food-logging application-taking chronotype and social jetlag into consideration. Higher total daily intake of seafood, EPA, and DHA was associated with a morning chronotype and less social jetlag. Intake at breakfast and lunch related to morningness and less social jetlag, with breakfast showing the strongest association. These findings suggest that both the quantity and timing of seafood, EPA, and DHA intake may be related to sleep patterns; however, causal relationships cannot be inferred due to the cross-sectional design.
