Prospects for developing sleep-related functional foods: Use of electroencephalography for objective sleep measurement

The development of sleep-enhancing food products can improve sleep quality. Understanding the relationship between food consumption and sleep is essential for selecting suitable ingredients for these products. Electroencephalography is a valuable tool for identifying foods and raw materials used in sleep-promoting products, providing critical insights into their effectiveness. This review examined the relationship between food consumption and sleep based on research from 2004 to 2024 utilizing electroencephalography tools in human and animal models. The effects of food intake on sleep were examined during the initial stage, slow-wave sleep, and the subsequent stage, rapid eye movement, with measurable parameters recorded. The intake quantity and concentration of specific foods or ingredients were analyzed in human and animal models, considering both normal sleep patterns and sleep disorder models. The analysis revealed that foods associated with sleep, as determined by electroencephalography testing, can be classified into six categories: essential oils, Chinese herbal medicines, plant and fungi extracts, tea and cocoa, probiotics and prebiotics in fermented foods, and food supplements. All the food types predominantly influenced the initial stage of sleep, specifically slow-wave sleep during non-rapid eye movement. In contrast, foods containing Chinese herbal medicines or extracts demonstrated a significant effect on the rapid eye movement stage. These findings provide valuable insights into the development of functional foods aimed at improving sleep quality.