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Old Fri, Oct-22-04, 21:06
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Quote:
Originally Posted by toopoles
does anyone know or ar there any studies about vitamin d production and our sleep cycles? I know I must be short of this vitamin in the winter so I was wondering if that also affected the sleep cycles.


Kinda...
Vitamin D is well known for its effects on helping to maintain normal calcium levels, but it also exerts influence on the brain, spinal cord, and hormone-producing tissues of the body that may be important in the regulation of mood.19 A double-blind controlled study found that mood improved in healthy people without SAD who received 400 or 800 IU per day of vitamin D for five days in late winter.20 However, no difference in vitamin D levels has been observed between people with seasonal depression and those without,21 22 and the antidepressant activity of light therapy has been shown to be independent of changes in levels of vitamin D.23 A large study of women found that supplementation with 400 IU per day of vitamin D had no impact on the incidence of winter depression.24 Any benefits of vitamin D on SAD remain unproven.
http://www.vitacost.com/science/hn/...ve_Disorder.htm

J Nutr Health Aging. 1999;3(1):5-7. Related Articles, Links


Vitamin D vs broad spectrum phototherapy in the treatment of seasonal affective disorder.

Gloth FM 3rd, Alam W, Hollis B.

The Department of Medicine, The Union Memorial Hospital, Baltimore, Maryland 21218-2895, USA.

Seasonal Affective Disorder (SAD) is prevalent when vitamin D stores are typically low. Broad-spectrum light therapy includes wavelengths between 280-320 nm which allow the skin to produce vitamin D. This study was designed to test the hypothesis that vitamin D deficiency might play a role in SAD. A prospective, randomized controlled trial was conducted in a group of 15 subjects with SAD. Eight subjects received 100,000 I.U. of vitamin D and seven subjects received phototherapy. At the onset of treatment and after 1 month of therapy subjects were administered the Hamilton Depression scale, the SIGH-SAD, and the SAD-8 depression scale. All subjects also had serum levels of 25-hydroxyvitamin D (25-OH D) measured before and 1 week after intervention therapy. All subjects receiving vitamin D improved in all outcome measures. The phototherapy group showed no significant change in depression scale measures. Vitamin D status improved in both groups (74% vitamin D group, p < 0.005 and 36% phototherapy group, p < 0.01). Improvement in 25-OH D was significantly associated with improvement in depression scale scores (r2=0.26; p=0.05). Vitamin D may be an important treatment for SAD. Further studies will be necessary to confirm these findings.
http://www.ncbi.nlm.nih.gov/entrez/...6&dopt=Abstract

Some other studies showed administration of the active form of vitamin D inhibited slow wave sleep (but increased waking/REM sleep alternation), or delayed sleep when given at night. I don't know that either of these I'm just paraphrasing here have direct application to the normal administration of vitamin D. (But on the other hand, if you consider that sunlight enhances vitamin D, I suppose it's not such a jump to say that it's logical that some kind of anti-sleep effect of vitamin D would be seen. But to make an even further albeit tenuous jump... just because you are outside in the day when it's light out, doesn't mean you can't sleep that night. I think if I'd get any takeaway from this it might be that 'twere I to take a vitamin D supplement, I'd be doing it during the day rather than right before bed.)
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