There have been quite a few questions/posts around the web on the best time of the day to supplement with Vitamin D3 with regards to improving sleep (or at least not disturbing sleep).
Most views seems to be based on experience and/or conjecture.
Does anyone know if there have been any actual studies carried out, in this area?
(please provide links/refs....)
I think most of the opinions out there on morning/evening D3 are simply n=1 experiences, including some on previous paleohacks threads:
I did manage to find two studies on resolving sleep problems by correcting vitamin D deficiencies via supplementation:
The first study isn't of much help - the abstract only indicates vitamin D is provided over 3 months, no mention of doses or timing. Resolving the vitamin D deficiency helped improve sleep in this study. http://www.ncbi.nlm.nih.gov/pubmed/22372707
The second study is notable here because sleep improved substantially on a large vitamin D supplement (50,000 IU) provided only once per week, suggesting that time of day may not be relevant. That being said, this is a report on a single patient, albeit in a clinical environment. http://www.ncbi.nlm.nih.gov/pubmed/21206551
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