An early bedtime improves children’s gut health by increasing the number of beneficial bacteria

Children who go to bed early have a richer gut microbiome and better sleep efficiency, paving the way for potential interventions that leverage the gut-brain connection to improve sleep quality and overall health.

Test: Characteristics of intestinal flora in children going to bed early and behind schedule. Image source: Africa Studio / Shutterstock

In a recent study published in the journal Scientific reportsresearchers examined gut microbial composition and metabolite expression in 88 vigorous children to assess the impact of sleep timing and rhythm on gut health and related outcomes.

Multi-omics sequencing of participants’ stool samples revealed that gut microbial composition (beta diversity; P = 0.045) differed significantly between early sleepers (before 9:30 p.m.) and behind schedule sleepers. Specific species, e.g Akkermansia muciniphila (P = 0.00024), Alistipes finegoldii (P = 0.028) i Holdemania filiformis (P = 0.0077) were noticeably more common in early sleepers. Alpha diversity indices (Simpson’s index, P = 0.0011; Shannon’s index, P = 0.0013) confirmed these findings and showed significantly greater diversity and abundance of beneficial gut microbiota in early sleepers compared to behind schedule sleepers.

Collectively, these findings support and underscore the importance of refraining from “early bedtime…” in children (and potentially adolescents), highlighting the beneficial effects of good and regular sleep habits. It may also constitute the basis for future pharmacological interventions against sleep disorders by exploiting the previously untapped gut-brain axis.

Background

Sleep, a state of altered consciousness and reduced activity (physical and mental) are indispensable for both recovery and normal growth and development. Recent research suggests that sleep plays a key role in maintaining order, enabling the removal of toxic metabolites from the brain, anabolism in muscles and better overall recovery.

In today’s world, where the incidence of chronic diseases is rapidly increasing, sleep (along with other good health behaviors such as diet and physical activity) is increasingly being examined for its relationship to human health and well-being. Growing evidence suggests that adequate sleep and regular sleep hours can significantly reduce the risk of cardiovascular disease, neurological disorders, obesity and diabetes. These findings are particularly critical in children and adolescents, where sleep has been shown to significantly modulate average growth and development.

Despite extensive research on the impact of sleep (particularly its duration) on children’s health, the potential impact of sleep on the intestinal microflora remains unknown. Although most school-age children are known to maintain regular activities on school days, some are expected to significantly change these habits (especially sleep hours) on weekends and holidays, potentially increasing the risk of adverse health outcomes.

“Research has shown that establishing early bedtimes and early mornings can have many benefits for children. These benefits include getting enough sleep and establishing regular sleep patterns, which are crucial to children’s well-being and educational achievement. Although previous research has focused primarily on observing children’s sleep patterns and implementing interventions to improve these patterns, there is a significant research gap in examining children’s sleep from a physiological and metabolic perspective.”

About the study

This study aims to fill existing knowledge gaps by applying next-generation multi-omics sequencing to unravel the metabolic mechanisms (gut microbial composition and metabolic pathways) associated with different sleep durations and bedtimes. Data for the study were obtained from 88 vigorous children (aged 2–14 years) from Lanzhou City, Gansu Province, Northwest China (female n = 44). Children were excluded from the study if: 1. their parents had not successfully completed the author’s dairy and sleep course, 2. had taken antibiotics in the 30 days prior to the start of the study, and 3. were currently suffering from an antibiotic infection.

Data collection included pediatric assessment of participants’ birth weight, birth length, duration of daily physical activity, bowel frequency, meal frequency, and current height and weight. Additionally, a psychological assessment of the participants and their parents was conducted. Biological sample collection included blood and stool samples for multi-omics procedures.

“Sleep diary monitoring and recording includes: sleep time, how many times you woke up during sleep, how long did you sleep at night?, sleep efficiency (total sleep time/total time in bed), number of dreams, Sleep Quality Score. (1 is indigent, 5 – average, 10 – excellent), Time for a nap during the day (min), How long did you sleep at night? Total time spent in bed at night, nap time during the day. The analysis showed that the group that fell asleep early had significantly shorter “time to fall asleep” (P = 1e-06), fewer “night-waking incidents” (P = 0.015), and higher “sleep efficiency” (P = 9.9e- 06) compared to behind schedule sleepers.”

Metagenomic sequencing was performed using the DNBSEQ platform, followed by utilize of Metaphlan 3.0 software for participant-specific taxonomic profiling of the gut microbiome. Profiling of functional metabolic pathways was performed using the HUMANN 3.0 database. Specific pathways such as aerobic degradation of toluene I (P = 0.025), threonine metabolism superpathway (P = 0.027), and the second L-lysine biosynthetic pathway (P = 0.028) were found to be significantly increased in early sleepers, suggesting a distinct profile metabolic, which may be linked to improved gut health. Alpha and beta diversity indices were calculated in R software (version 4.0.3; vegan and ape packages). Finally, the effect of sleep on gut microbiome abundance profiles was assessed using permutational multivariate analysis of variance (PERMANOVA).

Research results

The study design ensured that the 88 participants were equally divided into early sleep phase (bedtime before 9:30 p.m.) and behind schedule sleep phase (bedtime after 9:30 p.m.) groups, with equal representation of men and women in each group. Descriptive analysis of covariates (age, gender, daily behaviors, geographic distribution, physical activity) revealed no statistical differences at baseline between the early and behind schedule sleep cohorts.

Of note, early sleep participants significantly outperformed their behind schedule sleep counterparts on almost all sleep quality measures measured (P values ​​ranging from 1e-06 to 0.015). However, sleep duration, number of dreams, and nap duration were statistically indistinguishable between cohorts.

Significant differences were observed between cohorts in microbiome species composition and relative abundance, with early sleepers showing significantly higher abundances of the Bacteroidetes, Verrucomicrobia, and Firmicutes phyla (P = 0.045). Alpha and beta diversity at the genus level was also significantly higher in early sleepers.

“During the metabolic pathway analysis, it was observed that various metabolic pathways experienced significant increases. These pathways include the aerobic degradation of toluene I by o-cresol (P = 0.025), the aerobic degradation of toluene II to 4-methylcatechol (P = 0.025), the threonine metabolism superpathway (P = 0.027), the second pathway L-lysine biosynthesis (P = 0.028 ), TCA cycle with incomplete reduction (P = 0.039), the second route of L-ornithine biosynthesis (P = 0.040) and the initial step of formaldehyde oxidation (P = 0.041).”

Conclusions

This study provides the first evidence of a direct link between sleep and gut microbiota, highlighting the importance of early and regular sleep in younger children (ages 2–14). Early sleepers showed higher abundance of beneficial species such as Akkermansia muciniphila AND Alistipes finegoldii as well as increased activity in many metabolic pathways that support gut health. The results of the study showed that people who sleep early have a greater diversity and abundance of beneficial gut bacteria, which directly affects metabolic pathways and overall health. Links between sleep patterns and metabolic pathways may further pave the way for future pharmacological interventions to counteract sleep disorders.