Appraising the role of biotics and fermented foods in gut microbiota modulation and sleep regulation.

Sleep disturbances are increasingly prevalent, significantly impacting physical and mental health. Recent research reveals a bidirectional relationship between gut microbiota and sleep, mediated through the microbiota-gut-brain axis. This review examines the role of gut microbiota in sleep physiology and explores how biotics, including probiotics, prebiotics, synbiotics, postbiotics, and fermented foods, can enhance sleep quality. Drawing from animal and human studies, we discuss neurobiological mechanisms by which biotics may influence sleep, including modulation of neurotransmitters, immune responses, and hormonal regulation. Key microbial metabolites, such as short-chain fatty acids, are highlighted for their role in supporting sleep-related neurochemical processes. Additionally, this review presents dietary strategies and food processing technologies, like fermentation, as innovative approaches for sleep enhancement. Although promising, the available research has limitations, including small sample sizes, variability in biotic strains and dosages, and reliance on subjective sleep assessments. This review underscores the need for standardized protocols, objective assessments such as polysomnography, and personalized biotic interventions. Emerging findings highlight the therapeutic potential of gut microbiota modulation for sleep improvement, though further large-scale human trials are essential to refine strain selection, dosage, and formulation. This interdisciplinary exploration seeks to advance food-based interventions and holistic strategies for managing sleep disorders and improving quality of life.