Gut Health and Sleep: Children’s Bedtimes Impact Microbial Diversity in Gut Flora

There are significant differences in the composition and diversity of gut flora and metabolic pathways between children with an early vs late bedtime, which suggests an association between gut health and sleep. These are the findings of a study published in Scientific Reports.

Owing to the research gap in the physiologic and metabolic mechanisms associated with sleep in children, researchers compared the characteristics of gut flora and metabolic pathways in children with an early (before 9:30 pm) vs late bedtime (after 9:30 pm).

Eligible participants were healthy children aged between 2 and 14 years in China, all of whom underwent a standard assessment as well as psychologic analysis, based on sleep diary recordings. Biological samples, including feces and blood, were collected from participants, following which metagenomics sequencing and profiling of functional metabolic pathways were performed. Alpha and beta diversity were also analyzed.

A total of 88 children were enrolled in the study for a period of 14 days. Half of the total sample were boys. Of the total cohort, 44 had a bedtime before 9:30 pm and the remaining had a bedtime after 9:30 pm.

Researchers noted no significant differences between the 2 groups in terms of age, sex ratio, body mass index (BMI), bowel movements, hygiene habits, and physical activity.

The following results were observed from analyzing the gut flora and metabolic pathways of children:

• Children in the early- vs late-sleep group took a shorter time to fall asleep and woke up less frequently at night (P =1e-06 and P =.015, respectively). Sleep efficiency and sleep quality also varied between the 2 groups (P =9.9e-06 and P =.00016, respectively).
• The species composition, diversity, and abundance of gut flora was significantly different between the groups.
• Children with an early vs late bedtime had an abundance of phyla Bacteroidetes, Verrucomicrobia, and Firmicutes flora.
• Genera Akkermansia, Streptococcus, Alistipes, and Eubacterium were higher in abundance in the early- vs late-sleep group. Beta (P =.045) and alpha diversity measures, such as Simpson index (P =.0011) and Shannon index (P =.0013), were statistically significant at the genus level.
• At a species level, Akkermansia muciniphila, Holdermania filiformis, and Firmicutes bacterium CAG 95 were in higher abundance in the early- vs late-sleep group (P =.00024, P =.0077, and P =.012, respectively). Streptococcus sp A12 and Weissella confusa were also elevated in children with an early vs late bedtime (P =.022 and P =.025, respectively).
• A muciniphila and Alistipes finegoldii were positively associated while Clostridium sp CAG 253 were negatively associated with time to fall asleep. A finegoldii was also positively associated with total sleep duration, but negatively associated with sleep efficiency. A finegoldii, A muciniphila, A finegoldii, and H filiformis were all negatively associated with sleep quality.
• Analysis of metabolic mechanisms showed an increase in pathways of aerobic breakdown of toluene, threonine metabolism, L-lysine biosynthesis, TCA cycle, L-ornithine biosynthesis, and formaldehyde oxidation.

Limitations of the analysis included incomplete information on the metabolic mechanisms associated with gut microbiota of children, as the relationship between gut flora and small molecule metabolism was not investigated; small sample size that limited generalizability to all children with an early bedtime; and sleep habits were reported by parents who were not monitored for their sleep patterns.

Overall, the researchers concluded, “[The results] emphasized the importance of sufficient sleep in promoting healthy cognitive and physical development in children. The outcomes of this examination offer a fresh perspective for exploring pharmacological approaches to address sleep disturbances in pediatric patients.”