Effectiveness of Melatonin-Containing Foods on Promoting Sleep: A Scoping Review.

Melatonin plays a crucial role in managing the body's sleep-wake cycle, and its natural occurrence in certain foods has generated interest in dietary interventions to improve sleep. This scoping review explores the impact of consuming foods that naturally contain melatonin on various sleep quality parameters. The literature was obtained through four major databases: PubMed, Scopus, CINAHL, and Web of Science using PRISMA guidelines. A total of 19 articles were included, comprising 14 interventional trials and 5 cross-sectional studies. Key data were extracted on melatonin sources, dosages, sleep assessment methods, and reported effects on sleep. The quality of articles included was evaluated using the Joanna Briggs Institute (JBI) appraisal tools. The findings of interventional studies suggested that melatonin-rich foods, including Montmorency tart cherries, Jerte Valley cherries, tomatoes, and kiwifruit, may contribute to improvements in sleep quality, duration, and efficiency, particularly among individuals experiencing sleep disturbances; however, the findings remain heterogeneous. Observational studies also suggested possible associations between higher intake of melatonin-rich foods and favorable sleep-related outcomes, including sleep quality, circadian rhythm regulation, and reduced social jetlag, although findings were heterogeneous across populations and study designs. However, studies were limited by variability in population, timing of consumption, melatonin dosage, intervention duration, and sleep assessment tools. Most of the studies focused on a narrow range of foods, despite the increased availability of other melatonin-rich options that remain underexplored. Future research should prioritize the use of objective tools to assess sleep and investigate a more diverse range of dietary melatonin sources to gain a better understanding of their potential role in sleep regulation.