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.

Reference

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

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.

Serum Vitamin D Predicts Cognitive Performance in Adults

Much of the research on the relationship between vitamin D and cognitive function has been conducted on older people or individuals who have a diagnosis of Alzheimer’s Disease or other dementia. This is because older people are less able to synthesise vitamin D in their skin and because dementia is typically a disease of aging. A study published in August 2015 looked at the relationship between vitamin D status and cognitive function in two cohorts of healthy individuals; those aged 30-60 and 60+. Research on disease-free groups is important because it allows us to look at the potential effect that nutritional deficiency has on the general population and on sub-clinical (no diagnosis) functioning. That is to say that we can learn more about how dietary insufficiencies might be affecting the general population long before disease onset. This information allows us more opportunity to intervene with treatment.

In this study of vitamin D in the blood were strongly associated with the degree of cognitive impairment on tests of visual spatial memory (recalling and recreating a complex shape) and processing speed. In this study lower levels of vitamin D were associated with poorer performance on these tests even in people aged 30.  This study complements a growing body of research that is demonstrating a relationship between vitamin D status and brain function (including influence on mood and anxiety disorders).

There is also growing concern worldwide about the ‘pandemic’ of vitamin D deficiency and the many health concerns it is associated with such as osteoporosis, fractures, and increased risk of some cancers and autoimmune diseases. It is estimated that at least 50% of people are vitamin D deficient and the situation is worse for those of with dark skin as the melanin pigment blocks the action of vitamin D synthesis in the skin. Food sources of vitamin D include oily fish (salmon, sardines and mackerel), eggs and fortified cereals, though few people are eating sufficient amounts of these foods to keep their levels topped up, and vegetarians and vegans need to be very thoughtful about their food/supplement choices to ensure adequate levels.

Reference

Darwish, H., Zeinoun, P., Ghusn, H., Khoury, B., Tamim, H., and Khoury, S. J. (2015). Serum 25-hydroxy vitamin D predicts cognitive performance in adults. Neuropsychiatric Disease and Treatment, 11, 2217–2223.