What impact does short-term sleep restriction have on gut microbiome?

Recently, scientists in the United States published a study in the journal Scientific Reports investigating the impact of inadequate sleep on gut bacteria composition and gut barrier function. It has been suggested that gut bacteria may play a role in the negative health effects of poor sleep, but the extent of this in humans is not well understood.

The participants for the study were individuals between the ages of 17 and 45 who were of normal weight, had a usual sleep schedule of 7-9 hours per night, did not have any chronic health conditions, or had taken antibiotics or other supplements recently.

The study used a randomized crossover design in which the participants alternated between two conditions, getting 7-9 hours of sleep per night (adequate sleep, AS) or 2 hours of sleep per night (sleep restriction, SR) for 3 days each. The order in which they completed the AS and SR conditions was randomized and there was a 21-day washout period if SR preceded AS and a 7-day washout period if AS preceded SR. The participants were given a balanced diet and encouraged to engage in light exercise during both conditions.

After 48 hours of AS/SR, the participants provided stool samples which were analyzed for bacterial composition. DNA was extracted and analyzed using 16S rRNA sequencing, and gut permeability was tested using a dual sugar absorption test after 72 hours of AS/SR. In this test, participants consumed a drink containing two sugars, mannitol and lactulose, and the urine collected over the next five hours was examined to measure the gut permeability.

High-performance liquid chromatography (HPLC) was used to measure sugar concentrations, and fasting blood samples were collected on specific days to quantify levels of high-sensitivity C-reactive protein (hsCRP) and cortisol. Linear mixed models were used to assess differences in serum biomarkers, gut microbial diversity, and intestinal permeability between the SR and AS conditions.

The study found that participants slept for an average of 125 minutes per night during SR and 449 minutes per night during AS. Energy intake was slightly higher during SR, but there were no significant differences in estimated energy balance between the two conditions. No participant consumed any foods or beverages other than those provided by the study.

The study found that cortisol levels decreased from SR day 1 to SR day 4 and remained lower on SR day 4 compared to AS day 4. However, there were no differences in hsCRP concentrations or urinary volume between the two conditions. Stool consistency was similar between SR and AS, and there were no differences in the excretion of mannitol or lactulose, or in the lactulose-to-mannitol ratio.

Gut microbial diversity, as measured by the α-diversity index, was 21% lower during SR than during AS. However, there were no differences in other indices of microbial diversity, such as Simpson or Shannon diversity. The study found no significant differences in the relative abundance of prevalent taxa, but did observe a significant difference in the relative abundance of one amplicon sequencing variant (ASV) within the Ruminococcaceae family. This suggests that SR might lead to a decrease in community richness due to the loss of rare taxa.

In summary, the study found that restricting sleep to 2 hours per night for three consecutive days can lower community richness of gut microbiota without affecting intestinal permeability or relative abundances of prevalent taxa. This loss of community richness might be due to the loss of rare taxa, which could have negative effects on the functional repertoire of gut microbiota in populations with repeated sleep restrictions.

References:

Karl, J. P. et al. (2023). Severe, short-term sleep restriction reduces gut microbiota community richness but does not alter intestinal permeability in healthy young men. Scientific Reports, 8(1), doi: 10.1038/s41598-023-27463-0. Retrieved from https://www.nature.com/articles/s41598-023-27463-0

Lomte, T. S. (2023, January 10). What impact does short-term sleep restriction have on gut microbiome? News Medical. Retrieved January 10, 2023, from https://www.news-medical.net/news/20230109/What-impact-does-short-term-sleep-restriction-have-on-gut-microbiome.aspx