* Lack of sunlight
* Everyone who lives more than 35 degrees latitude north or south of the equator is at risk of vitamin D deficiency in the winter months
* Dark or black
skin needs up to 10 times the amount of sun than light
skin to absorb vitamin D in their
skin
* Wearing sunscreen - prevents absorption of UVB rays that create vitamin D
* Lack of vitamin D co-factors - magnesium (most important co factor), zinc, vitamin K2, boron, and a tiny amount of vitamin A
* Magnesium and calc