By Craig Weatherby
Sleep deprivation is at epidemic levels in the U.S. … and worldwide as well.
There’s considerable evidence that lack of sleep promotes major health problems, including cardiovascular disease, depression, and obesity.
For example, see “Heart Study Finds Sleep a Lifesaver”.
To the extent that seasonal affective disorder (SAD) disrupts sleep patterns, light therapy usually helps (Pail G et al. 2011) ... and vitamin D supplements may help, too (Stumpf WE et al. 1989; Gloth FM 3rd et al. 1999).
Recent research suggests that omega-3s from fish may also help reduce SAD symptoms … see “Can Omega-3s Help Banish the “Winter Blues?”.
Lack of nighttime sleep leads to daytime drowsiness … and there’s growing evidence that vitamin D deficiency can cause or worsen the situation.
Study links daytime sleepiness to low vitamin D levels
A clinical study linked, for the first time, daytime sleepiness to low levels of vitamin D (McCarty DE et al. 2012).
The credibility of the correlation was bolstered by the fact that daytime sleepiness was greatest in those with the lowest vitamin D levels … and vice versa.
A team from Louisiana State University Health Sciences Center recruited 81 people diagnosed with a sleep disorder – mostly obstructive sleep apnea – at the LSUHSC sleep clinic.
The volunteers’ vitamin D blood levels were measured, and the extent of their daytime sleepiness was determined using a standard test (Epworth Sleepiness Scale).
The Louisiana State team found that in patients without vitamin D deficiency, sleepiness scores rose as vitamin D levels fell.
Among the patients who were vitamin D deficient (defined as lower than 20 ng/mL), sleepiness was directly correlated with vitamin D levels … but only in black people, not white.
The authors believe that this makes some sense because – compared with light skin – dark skin blocks more of the UV sunrays needed to produce vitamin D in the body.
(Frankly, that’s an odd interpretation of the skin-color-based finding, since the correlation was not seen in white subjects who were equally vitamin D deficient, despite having light skin.)
The study could not determine whether vitamin D deficiency alone causes daytime drowsiness.
However, research from the authors and other teams suggests that low levels of vitamin D may promote daytime drowsiness … directly or by promoting or exacerbating chronic pain (Huang W et al. 2012).
It seems that daytime alertness can now join the many good reasons to ensure vitamin D adequacy.
You can best do that by eating fatty fish, taking supplements, and getting adequate (not excessive) exposure to UV sunrays.
Andersen ML, Tufik S. Vitamin D as an underlying factor in sleep-related issues. J Clin Sleep Med. 2012 Dec 15;8(6):699. doi: 10.5664/jcsm.2268.
Gloth FM 3rd, Alam W, Hollis B. Vitamin D vs broad spectrum phototherapy in the treatment of seasonal affective disorder. J Nutr Health Aging. 1999;3(1):5-7.
Gominak SC, Stumpf WE. The world epidemic of sleep disorders is linked to vitamin D deficiency. Med Hypotheses. 2012 Aug;79(2):132-5. doi: 10.1016/j.mehy.2012.03.031. Epub 2012 May 13.
Hoeck AD, Pall ML. Will vitamin D supplementation ameliorate diseases characterized by chronic inflammation and fatigue? Med Hypotheses. 2011;76(2):208-213.
Huang W, Shah S, Long Q, Crankshaw AK, Tangpricha V. Improvement of Pain, Sleep, and Quality of Life in Chronic Pain Patients With Vitamin D Supplementation. Clin J Pain. 2012 Jun 13. [Epub ahead of print]
Humble MB. Vitamin D, light and mental health. J Photochem Photobiol B. 2010 Nov 3;101(2):142-9. doi: 10.1016/j.jphotobiol.2010.08.003. Epub 2010 Aug 10. Review.
McCarty DE, Reddy A, Keigley Q, Kim PY, Marino AA. Vitamin d, race, and excessive daytime sleepiness. J Clin Sleep Med. 2012 Dec 15;8(6):693-7. doi: 10.5664/jcsm.2266. McCarty DE. Resolution of hypersomnia following identification and treatment of vitamin d deficiency. J Clin Sleep Med. 2010;6(6):605-608.
Pail G, Huf W, Pjrek E, Winkler D, Willeit M, Praschak-Rieder N, Kasper S. Bright-light therapy in the treatment of mood disorders. Neuropsychobiology. 2011;64(3):152-62. doi: 10.1159/000328950. Epub 2011 Jul 29. Review
Stumpf WE, Privette TH. Light, vitamin D and psychiatry. Role of 1,25 dihydroxyvitamin D3 (soltriol) in etiology and therapy of seasonal affective disorder and other mental processes. Psychopharmacology (Berl). 1989;97(3):285-94. Review.