A new study reveals the relationship between sleep and the human gut microbiome.
The human gut microbiome can influence physical and mental health, particularly through the brain-gut-microbiome axis (BGMA). Disruption in the BGMA has been associated with a number of health consequences, such as gastrointestinal disorders, anxiety, depression, Parkinson’s disease, as well as a decrease in cognition. Previous studies have demonstrated how bacteria play a role in neurological, hormonal, and immunological responses in the body. Therefore, understanding how bacteria and BGMA function to affect human health has become an important research topic, which now may include the link between the gut microbiome and sleep quality.
Sleep has been strongly linked to the immune system, however, sleep has not yet been well studied in BGMA research. Sleep quality has been associated with cognitive and behavioural functioning. Interleukin cytokines, such as IL-6, have been identified as key molecules, where poor sleep results in higher IL-6 concentrations. In recent research published in PLOS ONE, scientists in the United States sought to better understand this relationship.
The researchers analyzed the gut microbiome of 26 participants in relation to their sleeping patterns. Participants were asked to wear an Actiwatch to record and measure sleep habits, such as average bed time, average wake time, time in bed, total sleep time, onset latency, sleep efficiency, wake after sleep onset, and number of awakenings. Their gut microbiome and selected biomarkers, such as IL-6, were measured from saliva and fecal swab samples.
The results found that sleep efficiency and total sleep time were positively associated with microbiome diversity and richness. In contrast, wake after sleep onset was negatively associated with microbiome diversity, thus suggesting that a diverse gut microbiome promotes healthier sleep. They also saw a clear link between IL-6, the diversity of the gut microbiome, and sleep. The study showed positive correlations between IL-6 and time in bed and total sleep time, as well as with gut microbiome richness.
Although the researchers identified the presence of a clear association, the key mechanisms and molecules involved with how these systems are linked remain unknown. The study notes that their current findings are only limited to men, however, they would expect that the findings would be similar in women. Nonetheless, their research may help the discovery of sleep improvement mechanisms through the alteration of the gut microbiome.
Written by Maggie Leung, PharmD.
Smith, R. P., Easson, C., Lyle, S. M., Kapoor, R., Donnelly, C. P., Davidson, E. J., … Tartar, J. L. (2019). Gut microbiome diversity is associated with sleep physiology in humans. Plos One, 14(10). doi: 10.1371/journal.pone.0222394
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