We aim to test whether quality of sleep in working people can be improved by modulating the gut microbiome with probiotics.

A good night´s sleep is essential for our attention, cognition and mood. Sleep fragmentation can therefore lead to poor performance, loss of productivity, and errors, incidents and accidents in the workplace. Sleep disruption has further been associated with metabolic and cardiovascular diseases, psychiatric diseases and cancer.The gut microbiome and its metabolites exhibit diurnal rhythmicity in response to food intake and influence human clock gene expression and sleep duration. Sleep fragmentation causes dysbiosis and hormonal disturbances. First data from animal experiments and small human studies imply that modulation of the gut microbiome may improve sleep quality and thereby mental and physical health. Probiotics can alter the gut microbiota composition and can mitigate positive effects on psychiatric symptoms via the microbiome gut-brain axis by metabolites such as short-chain fatty acids (SCFA) that can pass the blood-brain barrier and thereby comprise a potential strategy to improve sleep quality and other quality of life related outcomes. Evidence on the effect of probiotics to improve quality of sleep is available from several small-scale clinical studies in different populations. The benefit seems to be stronger in people under physical or mental stress.

Also, a large marketing survey conducted in Germany in over >10.000 consumers indicated that a multispecies probiotic, that has been described to improve inflammation, gut barrier dysfunction and immune function in different patient cohorts is able to improve sleep quality and quality of life, however since this study was non-randomized, a bias cannot be excluded.

Understanding the interaction between the gut microbiome, chronobiology and health is therefore of high importance and in line with the United Nations' Sustainable Development Goal 3 of the 2030 Agenda for Sustainable Development to "ensure healthy lives and promoting well-being for all at all ages".

Inclusion criteria

• Age >18
• Working
• Signed Informed Consent;
• Willing to accept use of all encoded data, including publication, and the confidential use and storage of all data for at least 15 years
• Pittsburgh Sleep Quality index score of >5 Exclusion criteria
• Diagnosed with a gastrointestinal infection within 4 weeks prior to screening
• Severe gastrointestinal diseases (e.g. inflammatory bowel diseases)
• Received any of the following products/medication within 4 weeks prior to screening: systemic antibiotics, prokinetics, prebiotic supplements, probiotic supplements
• Concomitant diseases or other circumstances that suggest that the patients are not eligible for participation in the study

Depending on the results, according to the grant contract, IPR will be shared among partners and after these discussions IPD may be shared. Microbiome sequencing data will be deposited in a public repository

placebo, outcome assessors are blinded to the group allocation