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Can supplemental vitamin D improve sleep?

Vitamin D levels seem to be correlated with sleep quality. But correlation doesn’t necessarily equal causation

Study under review: The effect of vitamin D supplement on the score and quality of sleep in 20-50 yearold people with sleep disorders compared with control group

Introduction

The optimal amount of sleep varies from person to person. Most adults require[1] at least seven hours per night on a regular basis. Sleeping less than this is associated with numerous adverse health outcomes, including cardiometabolic diseases, impaired immune function, impaired cognitive performance, and even death. Most people suffering from a lack of sleep tend to also[2] have a lower satisfaction with their economic, social, and family situations, but certain disease states play a role as well. Insomnia is the most common[3] specific sleep disorder, with approximately 30% of adults reporting problems with insomnia and approximately 10% suffering from chronic insomnia.

It has recently been hypothesised that vitamin D may play a role[4] in maintaining good sleep and that chronically low levels of vitamin D could result in impaired sleep. Vitamin D’s theoretical interactions with sleep are summarized in Figure 1. However, direct investigations of the role of vitamin D supplementation in sleep disorders is lacking. Some studies[5] have shown associations between low vitamin D levels in the blood and sleep quality. Other sleep disorders, such as obstructive sleep apnea[6], have also been associated with lower vitamin D levels. While this limited evidence is primarily observational, meaning we can't be sure about cause and effect, it was enough to inspire the study authors to investigate the potential effect of vitamin D supplementation on sleep quality in a randomised controlled trial.

Poor sleep is a common health concern that can affect quality of life and potentially have negative consequences for an individual’s health. Observational evidence has suggested a correlation between sleep quality and vitamin D levels, but the evidence is sparse and interventional evidence is lacking. This study is the first randomised control trial designed to investigate whether vitamin D supplementation improved sleep quality.
Figure 1: How vitamin D deficiency may interact with sleep

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Other Articles in Issue #34 (August 2017)