Probiotics Show Limited and Inconsistent Effects on Sleep Quality and Duration

What's new

A meta-analysis of 39 randomized controlled trials investigated whether probiotic supplementation could improve sleep outcomes [1]. The findings suggest that while probiotics might offer some benefits, these effects are generally small, inconsistent, and often based on a limited number of studies. The analysis included data from men and women, primarily without existing health conditions or sleep disorders, who took various single-strain and multi-strain probiotic supplements daily for periods ranging from 4 to 12 weeks [1].

The science behind it

The meta-analysis revealed that probiotics were associated with improvements in subjective sleep quality across 10 studies [1]. When examining objectively measured outcomes, the researchers found that probiotics increased total sleep time by an average of 14 minutes, based on data from three studies. Additionally, the time spent awake after initially falling asleep decreased by approximately 5 minutes, though this finding was derived from only two studies [1].

The authors noted that the observed benefits were often inconsistent, which they attributed to the wide variation in the probiotic interventions used. Different probiotic strains are known to have distinct effects, and the lack of standardization in the types and dosages of probiotics across the included studies likely contributed to the mixed results [1]. The potential mechanism for probiotics influencing sleep is thought to be through their ability to modulate the gut microbiota, which can, in turn, affect various physiological processes, including those related to sleep regulation [1]. However, the specific pathways and the extent of this influence remain areas for further investigation.

What it means in practice

For individuals considering probiotics to improve sleep, the current evidence suggests that any potential benefits are likely to be modest. While some subjective improvements in sleep quality were reported, and minor increases in total sleep time were observed, these effects were not robust across all studies or all types of probiotics [1]. The variability in outcomes underscores that not all probiotics are created equal; the effects can be highly dependent on the specific strain or combination of strains used [1].

Given the small effect sizes and the inconsistency in findings, probiotics are unlikely to be a primary solution for significant sleep disturbances. Instead, they might be considered as a complementary approach for individuals seeking marginal improvements in sleep, particularly if they are already addressing foundational sleep hygiene practices. It is crucial to remember that the research in this area is still developing, and more targeted studies with specific probiotic strains are needed to draw more definitive conclusions.

Caveats

This meta-analysis, while comprehensive, highlights several limitations in the current body of evidence. The small number of studies contributing to objective sleep outcomes (total sleep time and wake after sleep onset) means these findings should be interpreted with caution [1]. The heterogeneity of probiotic interventions, including different strains, dosages, and durations, makes it challenging to pinpoint which specific probiotics, if any, are most effective for sleep [1]. Furthermore, most participants in the included studies did not have diagnosed sleep disorders, meaning the results may not be generalizable to populations with clinical insomnia or other significant sleep issues [1]. Future research should focus on larger, more standardized trials using specific probiotic strains and include populations with defined sleep disturbances to better understand the potential role of probiotics in sleep health.

Source: [1]