“Because vitamin D is so cheap and so clearly reduces all-cause mortality, I can say this with great certainty: Vitamin D represents the single most cost-effective medical intervention in the United States.” ~ Dr. Greg Plotnikoff, Medical Director, Penny George Institute for Health and Healing, Abbott Northwestern Hospital in Minneapolis
Vitamin D2 is made by plants. Vitamin D3 is made when the skin is exposed to the sun. Foods can be altered to have vitamin D2 or D3 in them. As always the natural source is the best. If that is not possible, like you live in a cloudy area, you can also get them in supplements.
Vitamin D’s job is to maintain normal blood levels of phosphorous and calcium. It helps calcium to be absorbed which forms and keeps your bones strong.