[surferjoe2007]

Vitamin D is pretty major. For many even more major than calcium, since their vitamin D tends to be the bottleneck to their calcium. I've seen recommendations from 1,000 iu to 10,000 iu. I think 2,000 iu is best though a little more doesn't hurt. Over 10,000 iu may reduce the benefits, and the TUI (recommended tolerable upper limit) is set at 4,000 iu presumably to provide a factor of safety. Though it doesn't actually become harmful until an order of magnitude higher than that daily for months on end; you'd have to blow several hundred dollars on most supplements to actually hurt yourself with unwanted calcium deposits. Going outside is also a good way to go and it helps your mood and eyesight too on top of the vitamin D.

Calcium is used not only for bones but also pretty much everything. It's some major stuff. And since how much calcium you actually get is limited by vitamin D, vitamin D is pretty major. Too much dietary calcium can even make calcium levels worse.