Table of Contents
What is the best time to take Vitamin D?
With breakfast or lunch. If you do what I do (take 50K IU once a week), or you follow the vitamin D3 alternative to flu shots for the flu season, do NOT take it in the afternoon or especially in the evening. It can disrupt sleep easily.
At the low dose (2K to 8K IU for daily intake), taking it in the evening might not be noticeable. But I think it is likely a bad idea even if it’s circadian influence is subtle. In a free-living human, vitamin D production would peak in the afternoon, after the bulk of sun exposure, and during the time when the sun’s rays are as vertical as they will get. Taking vitamin D in opposition to this natural rhythm seems decidedly unwise. [Source]
Can a deficiency in Vitamin D cause Depression?
Certainly. But it is not necessary; there are plenty of other causes of depression.
Vitamin D serves a hormone role, one manifestation of which is an influence on cellular energy metabolism—specifically aerobic energy. The brain is a high-energy tissue, so when brain metabolism lags, depression can result. Vitamin D deficiency is one cause. Insufficient thyroid hormone, progesterone or testosterone is another. Toxic influences that sabotage energy are another, like heavy metal poisoning, estrogen dominance, fluoride toxicity, and mitochondrial antimetabolites. Metabolic glitches like insulin resistance. Chronic inflammation is one way to get estrogen dominant. Lack of blood perfusion of the brain (coagulopathy), and on and on. So if you or a loved one has depression, normalization of vitamin D levels with sunlight and vitamin D3 supplements is something to consider. But do not be surprised if is is not sufficient all by itself. [Source]
TL;DR: Anything that lowers brain metabolism can cause depression, including a vitamin D deficiency