Can Dietary Supplements Improve Sleep and Function in Shift Workers?

Overview

Shift workers often face disrupted sleep and reduced daytime performance due to circadian rhythm disturbances. This systematic review and meta-analysis evaluated whether dietary supplements (DSs) can improve sleep quality, daytime functioning, and mood among real-world shift work populations.

The review analyzed 12 randomized controlled trials involving 917 participants, comparing the effects of DSs such as melatonin, probiotics, herbs, and vitamins against placebos. The results suggest that DSs may play a meaningful role in improving sleep and alertness, though more robust research is needed.

Key Findings

Improved Sleep Quality
In eight trials, participants taking dietary supplements reported significantly improved sleep quality scores compared to those on placebos. However, substantial heterogeneity was noted, suggesting variation in supplement types, study design, and participant characteristics.

Enhanced Daytime Function
Seven studies indicated that DSs contributed to better daytime functioning, helping users stay more alert and productive. This effect was statistically significant, despite moderate variability across studies.

Limited Effects on Mood and Reaction Time
While sleep quality and daytime alertness improved, no significant benefits were found for depression, anxiety, or psychomotor vigilance. This indicates DSs may not directly enhance mood or cognitive speed under shift work conditions.

Strong Safety Profile
Across all studies, DSs were generally well tolerated. Mild side effects such as dizziness or headache were rare and transient. No participants dropped out due to adverse reactions, reinforcing their overall safety.

Considerations and Limitations

• Melatonin vs Non-Melatonin Supplements: No clear difference in effectiveness was observed between melatonin-based and other types of DSs.
• Heterogeneity: Differences in occupations, supplement formulations, and study quality led to high variability in results.
• Lack of Long-Term Data: Most studies did not include extended follow-up periods, limiting insights into the long-term efficacy of DSs.
• Limited Sample Sizes for Subtypes: The small number of studies for each supplement type prevented deeper analysis of individual products.

Conclusion

This meta-analysis supports the use of dietary supplements as a potentially valuable strategy for improving sleep quality and daytime function in shift workers. While the effects on mood and reaction time remain inconclusive, the safety and accessibility of DSs make them a promising option. Future research should prioritize high-quality, long-term trials across diverse shift work populations to validate and expand upon these findings.

Source:

Wu Y, Huang X, Zhong C, et al. Efficacy of Dietary Supplements on Sleep Quality and Daytime Function of Shift Workers: A Systematic Review and Meta-Analysis. Frontiers in Nutrition. 2025 (https://www.frontiersin.org/journals/nutrition/articles/10.3389/fnut.2022.850417/full).