Vitamin D Supplementation Improves Sleep Quality in Sleep Disorders

Vitamin D is a corticosteroid hormone that modulates the activity of hundreds of genes and plays an essential role in many other biological functions, including those linked to brain function and sleep regulation. I have previously reported research showing that serum levels of vitamin D predicted cognitive performance in adults

Consistently poor sleep should be considered a serious health concern. Inadequate sleep is linked to an increased risk of weight-gain, type 2 diabetes, heart disease and increased susceptibility to illness. Psychologically, poor sleep and sleep disorders are a common feature of many mental health concerns such as anxiety, bipolar disorder, post-traumatic stress disorder, Alzheimer’s Disease and other forms of dementia. Sleep problems such as insomnia or excessive sleep are diagnostic criteria for depression, the major cause of global disease burden. Rather than being just a symptom, impaired sleep can precede the onset of other symptoms and, conversely, improving sleep quality can help to alleviate symptom severity. So an accessible intervention that improves sleep is a valuable weapon in the mental health armoury. A recent clinical trial tested the effect of vitamin D supplementation on sleep quality.

Published in the journal Nutritional Neuroscience researchers at the Ahvaz Jundishapur University of medical science in Iran took a group of 89 people all of whom had sleep disorders characterised by long sleep latency (taking a long time to fall asleep) low sleep quality, duration and/or efficiency (spending a lot of time in bed but not much of it asleep). The participants were randomly assigned to two groups, one received a very high dose vitamin D supplement every fortnight for a total of eight weeks, the other received an identical looking placebo of edible paraffin.  

What was helpful about this study was that the researchers assessed the participants baseline vitamin D levels at the start of the trial and then again after it. This is important because it help to determine more accurately what blood levels might be most beneficial and helps to identify any individual differences between the participants that might influence the outcomes. At the start all the participants had insufficient levels of vitamin D (less than 29ng/mol of 25 (OH) D). At the end, as you might expect, the supplement group had sufficient levels and the placebo group had not changed significantly. In addition, at the end of the trial, the supplement group reported better overall sleep quality, with longer duration and reduced latency, suggesting that adequate vitamin D levels can help support healthy sleep.

It is important to note that the supplement administered in this trial was a very high, clinical dose. For example, the NHS recommends that adults in the UK consider supplementing with 10mcg of vitamin per day (equivalent to 140mcg per fortnight). The dose in this trial is equivalent to 1250mcg per fortnight. Very high dose supplements may be available on prescription and a blood test would need to be taken first to establish that there was definitely a nutritional deficiency.


Majid, M. S., Ahmad, H. S., Bizhan, H., Hosein, H. Z. M. & Mohammad, A. (2017). The effect of vitamin D supplement on the score and quality of sleep in 20–50 year-old people with sleep disorders compared with control group. Nutritional Neuroscience. Epub ahead of print. DOI: 10.1080/1028415X.2017.1317395


Disclaimer: This information is provided for information purposes only and should not be taken as advice or instruction. This information does not replace the advice of your doctor. Please consult an appropriate health professional if you believe you are experiencing a mental or physical health concern.