Dietary Supplement Interventions and Sleep Quality Improvement: A Systematic Review and Meta-Analysis

Background/Objectives: Sleep health impacts numerous domains of human health, and sleep deprivation has emerged as a significant public health concern. Multiple types of dietary nutrient supplementation, dietary intake, and the use of nutritional supplements to enhance sleep quality are recognized as effective methods to improve sleep quality. Methods: We aim to systematically evaluate the efficacy of dietary supplement interventions in sleep quality improvement across populations with sleep disorders and healthy individuals. We conducted a comprehensive literature search across PubMed, Web of Science, CNKI, ScienceDirect, Wiley, and CVIP databases. Sleep evaluation metrics included the Pittsburgh Sleep Quality Index (PSQI), sleep efficiency (SE), sleep latency (SL), total sleep time (TST), wake after sleep onset (WASO), and number of awake after sleep onset (NASO). Meta-analysis procedures were executed in Review Manager 5.3 and Stata 17.0, with heterogeneity quantified via I2 statistics. Results: This study, in total, included 28 randomized controlled trials. This meta-analysis’s results suggest dietary interventions significantly improved sleep outcomes: reduced PSQI (MD: −0.70, 95% CI: −1.37 to −0.03, p < 0.05), increased SE (+2.58 min, 95% CI: 2.01–3.16, p < 0.00001), prolonged TST (SMD: +0.23, 95% CI: 0.04–0.43, p < 0.05), and shortened SL (SMD: −0.24, 95% CI: −0.37 to −0.10) and WASO (SMD: −0.30, 95% CI: −0.48 to −0.12) (both p < 0.001). NASO showed a marginal reduction (MD: −1.57, 95% CI: −3.16 to 0.02, p = 0.05). Conclusions: These findings suggest that tryptophan, vitamin D, omega-3, zinc, and antioxidants may enhance sleep quality by decreasing SL, and WASO increases SE and extends TST, respectively.