Vitamin d and sleep quality
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Vitamin D Supplementation and Sleep Quality Improvement
Multiple studies and meta-analyses show that vitamin D supplementation can significantly improve sleep quality. Systematic reviews and meta-analyses found that people who received vitamin D supplements had better sleep quality scores compared to those who did not, with no reported side effects from supplementation Mirzaei-Azandaryani2022Abboud2022Majid2017. These improvements include reduced sleep latency, longer sleep duration, and better subjective sleep quality, especially in adults with sleep disorders .
Vitamin D Deficiency and Risk of Poor Sleep
Research consistently links low vitamin D levels with a higher risk of sleep disorders and poor sleep quality. Meta-analyses and large cohort studies found that vitamin D deficiency is associated with increased odds of sleep disorders, poor sleep quality, short sleep duration, and daytime sleepiness Gao2018Massa2015Singh2024. For example, older adults with low vitamin D levels were more likely to experience short sleep duration and lower sleep efficiency . Similarly, in pregnant women, lower vitamin D levels predicted poorer sleep quality, regardless of race .
Vitamin D and Sleep Variability
Recent research in healthy adults shows that poor vitamin D status is linked to greater variability in sleep timing and duration, even if it does not affect overall sleep duration or subjective sleep quality scores . This suggests that vitamin D may help stabilize sleep patterns, reducing night-to-night fluctuations in sleep.
Special Populations: Restless Legs Syndrome and Pregnancy
In people with restless legs syndrome (RLS), lower vitamin D levels are strongly associated with poorer sleep quality. Vitamin D may serve as a predictor for sleep problems in this group, though more research is needed to confirm if supplementation can help . Among pregnant women, vitamin D deficiency is also linked to worse sleep quality, highlighting the importance of screening and supplementation during pregnancy .
Contrasting Evidence: Vitamin D Intake vs. Serum Levels
While most studies focus on serum vitamin D levels or supplementation, one study in young adults (17–35 years) found no significant association between dietary vitamin D intake and sleep quality . This suggests that actual blood levels of vitamin D, rather than just intake, may be more important for sleep outcomes.
Mechanisms Linking Vitamin D and Sleep
Vitamin D receptors are present in brain regions that regulate sleep, and vitamin D is involved in melatonin production and circadian rhythm regulation, which may explain its impact on sleep quality .
Conclusion
Overall, the evidence suggests that maintaining adequate vitamin D levels—either through supplementation or ensuring sufficient serum concentrations—can improve sleep quality and reduce the risk of sleep disorders in various populations. However, the effect of vitamin D on sleep quantity and specific sleep disorders requires further research. Addressing vitamin D deficiency may be a simple and effective strategy to enhance sleep and overall well-being Mirzaei-Azandaryani2022Abboud2022Majid2017+5 MORE.
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