Vitamin D is the sunshine vitamin! A deficiency of vitamin D can result in rickets in children, and in adults, a lack of bone strength and density and even joint pain. Vitamin D is absolutely vital for the development and maintenance of bones and teeth and for absorbing and using calcium and phosphorus. In USA, with our short winter days and relative lack of sunshine, vitamin D becomes one of the most important vitamins we could take. Delicious orange liquid format makes it easy to take this critical vitamin.