The Consumption of Milk or Dairy Products and Sleep Quality: A Systematic Review and Meta-Analysis

Sleep quality is a key component of overall health and well-being. Despite its importance, many individuals experience sleep disturbances and seek various strategies to improve their sleep. The consumption of milk and dairy products has been linked to mood regulation and may influence sleep quality. However, the scientific evidence remains inconsistent, with studies reporting mixed and inconclusive results. The aim of the study is to investigate whether consuming milk and dairy improves sleep quality. A systematic review and meta-analysis were conducted using electronic databases PubMed, Science Direct, Embase, and Web of Knowledge. We included randomized controlled trials (RCTs) that evaluated the effects of the consumption of milk and dairy products on sleep quality. The meta-analysis was conducted using a random-effects model, calculating mean differences (MD) using Review Manager 5.4.1 and Jamovi 2.3.19.0. A total of 2,398 records were screened, and nine clinical trial studies were selected for the qualitative synthesis (systematic review). Four clinical trials met the criteria for inclusion in the meta-analysis following a thorough literature review. Meta-analysis results from the findings of clinical trials demonstrated that milk and dairy product consumption significantly reduced the Pittsburgh Sleep Quality Index (PSQI) total score (p < 0.01), regardless of treatment conditions or study groups, suggesting an overall improvement in sleep quality. The findings suggest that milk and dairy product consumption may contribute to improved sleep quality, as evidenced by self-reported measures in clinical trials. Further high-quality studies in humans are needed to confirm these effects.