Sleep Microbiome: Insights into Probiotics and Sleep Health

Abstract

Introduction
 The World Health Organization (WHO) defines probiotics as "live microorganisms that, when administered in adequate amounts, confer health benefits to the host." A number of scientific reports show that their effects extend beyond the immune and gastrointestinal systems, and that poor sleep quality and insomnia are an increasingly important social problem. Studies indicate that 30-50% of adults experience sleep problems. Sleep deficiencies are associated with higher rates of obesity, hypertension, type 2 diabetes, cardiovascular diseases, mental health disorders and increased risk of death. One promising way to help treat sleep problems is through the use of probiotics. Interaction through the gut-brain axis suggests that altering the gut microbiota may become a useful tool for improving sleep quality.
 Aim of the study
 The purpose of this study was to investigate the potential effectiveness of probiotics in improving sleep quality and treating insomnia.
 Materials and Methodology
 PubMed and Google Scholar databases were analyzed. Articles were searched in English using the following keywords: probiotics; sleep quality.
 Results 
 Probiotics resulted in a favorable cumulative effect on sleep quality as measured by the PSQI global questionnaire and a statistically significant positive effect on at least one of the components characterizing sleep quality (i.e., sleep latency, sleep length, sleep disturbance, daytime sleepiness). They allow to maintain a high percentage of slow-wave sleep, despite stressors, and indirectly affect sleep quality in athletes by reducing muscle soreness.
 Conclusion
 The results of studies to date indicate that probiotics are an effective, safe and clinically sound adjunctive method for improving sleep quality and treating insomnia. However, these studies are at an early stage and require further efforts using larger research groups.