If you do not supply the body with the calcium it needs, the body will take the calcium from the bones. This process can lead to weak, thin, brittle bones which are likely to fracture or break. If children do not get enough calcium, they will not grow as tall as nature may have planned and they can develop weak bones. In children, a lack of Vitamin D can cause rickets or deformed bones. This can lead to bone fractures.
Older adults require higher intake of Vitamin D because of poor absorption.
Vitamin D is added to milk which helps the body use the calcium and deposits it in bones and teeth. If you are in the sunlight a lot in the spring, summer and fall, you may only need extra Vitamin D during the winter months. The body does not store the Vitamin D from the summer to carry through the winter. If you spend most of your time indoors year round, you may need extra Vitamin D every day. If you are taking a multivitamin, read the label to see how much Vitamin D is added.