I've never witnessed Hypervitaminosis D in real life, although it's theoretically possible. Vitamin D deficiency is much more common. The plasma calcium level

I've never witnessed Hypervitaminosis D in real life, although it's theoretically possible. Vitamin D deficiency is much more common. The plasma calcium level is very complicated, and it can't solely blamed on Vitamin D intake. The functioning of the parathyroids and kidneys have as much, if not more, to do with it, and it's a complicated feedback mechanism. Any endocrinologists here who can explain it better? If you live near Seattle, or are not exposed to sunlight very often, then maybe some supplemental Vitamin D and calcium is in order. Disclaimer: This is not medical advice. Always consult your physician before changing medications / supplements :)