Gut Microbiome and Insomnia: A Mini-Review

Background: The gut microbiome (microorganisms present in our gut) has emerged as an important determinative factor in a variety of diseases and health conditions. One new area in which the role of the gut microbiome is of intense interest is its role in various neurological manifestations, including insomnia, the most common sleep disorder. In this mini-review, we aim to highlight the latest research developments concerning the association between the gut microbiome and insomnia and summarize gut-brain interaction for a better understanding of the role of microbiota in insomnia. Methods: Our search results included publications written in English from the year 2010 up to the year 2022. We used Pubmed, Google Scholar, and ScienceDirect to search for original articles pertaining to the relationship between the gut microbiome and insomnia using the following search terms: "Gut-brain Axis and Insomnia," "Brain and Gut Microbiome," " Gut-brain Homeostasis”, and "Circadian Rhythm and Gut Microbiome". Relevant articles from the reference list were reviewed in order to collect additional information. Results: Studies have shown that the microbiome-gut-brain axis is thus associated with the development of insomnia. The gut microbiome can have an important role in the development of insomnia. On the other hand, insomnia can also modulate the gut microbiome. However, scientific work in this field is limited as relevant scientific research is at the initial state. Conclusion: Bacteria present in the gut send signals to the brain via the vagus nerve by stimulating the afferent neurons of the enteric nervous system and influencing sleep quality and stress reactivity of the hypothalamic-pituitary-adrenal axis. The gut microbiome also communicates with the nervous system via the neuroendocrine pathway through various metabolic products. Insomnia also influences the structure and function of the gut microbiome.