A Yahoo! Health news report examines the impact of a vitamin D deficiency on sleep and the quality of sleep a person receives.
Although subtle, more than half of the world population is vitamin D deficient!
This is a big problem because sleep disorders are an epidemic due to vitamin D deficiency. This hurts the amount of sleep you get, the quality of your sleep, and your mood upon waking up.
We have this deficiency because of the way we live. We work inside, wear clothes, and use sunscreen. These are all realities of modern life, and they all take away from our vitamin D synthesis.
This is important to note, because you do not soak up D from the sun, per se. Rather, the interaction with UVB light and a cholesterol derivative in the skin causes D to be synthesized in the body.