Research indicates that diet, particularly dietary fiber, may significantly influence sleep quality.

Prior studies have revealed associations between various sleep states and the gut microbiome. Notably, a lack of bacterial diversity suggests that improving dietary habits could enhance sleep quality. However, no study has yet identified specific microbial species consistently linked to sleep quality and the exact foods that support their growth.

A new systematic review by Wang Che from China’s Shandong First Medical University analyzes 53 observational studies comparing the gut microbiota of individuals with sleep disorders to those without, encompassing 7,497 individuals with sleep disorders and 9,165 without.

The researchers discovered that the overall bacterial species diversity, termed alpha diversity, was significantly lower in individuals suffering from sleep disorders. Those with insomnia, obstructive sleep apnea, or REM sleep behavior disorder showed a notable decrease in anti-inflammatory, butyrate-producing bacteria like Faecalibacterium, alongside an increase in pro-inflammatory bacteria such as Collinsella.

This underscores the importance of dietary fiber, as Faecalibacterium produces butyrate, which provides energy for colon cells, strengthens the intestinal barrier, and reduces inflammation, according to recent studies.

Researchers highlighted that microbial signatures could serve as criteria to differentiate clinical symptoms from other sleep-related issues, thus enabling targeted treatments.

According to Catherine Maki from the National Institutes of Health in Maryland, this study aligns with her group’s ongoing research, which has found a similar connection between sleep and butyrate production from Faecalibacterium.

“Collectively, these consistent findings highlight plausible microbiome metabolic pathways that link sleep and host physiology, warranting direct testing in future mechanistic and interventional studies,” Maki notes.

“This meta-analysis supports the correlation between Faecalibacterium and insomnia,” states Elizabeth Holzhausen from Michigan State University. “However, since these studies are observational, causality cannot be established.”

One hypothesis is that insomnia may negatively impact dietary fiber intake, leading to reduced levels of Faecalibacterium. Alternatively, reduced butyrate from Faecalibacterium could influence sleep quality, as suggested by research findings.

Controlled intervention studies are essential for confirming the causal relationship, Holzhausen emphasizes.

The findings further highlight the vital role of the gut microbiome in our sleep health and reveal potentially significant changes in gut microbial signaling pathways related to sleep-influencing processes such as hormone release, metabolism, and inflammation.

Maki suggests that while it’s too early to recommend increasing fiber intake to improve sleep, there is emerging evidence regarding dietary aspects that may influence sleep.

Avoiding caffeine is advisable, as it may delay the onset of sleep, particularly in high doses or when consumed late in the day. Furthermore, alcohol can disrupt sleep, despite common misconceptions that it aids sleep. Additionally, eating too close to bedtime can impair sleep quality.

Some evidence suggests that certain foods, like tart cherry juice, can improve sleep quality. Improving overall dietary quality and increased fiber intake is linked to better sleep quality, though the specific dietary components influencing this relationship remain unclear.