what does milk provide
Milk and dairy products are a convenient source of calcium for many people. They are also a good source of protein and are fortified with vitamins D and A. At this time, however, the optimal intake of calcium is not clear, nor is the optimal source or sources of calcium.
Vitamin D is found in milk and vitamin supplements, and it can be made by the skin when it is exposed to sunlight in the summertime. But not all sunlight is created equal. Above 40 degrees latitude (north of San Francisco, Denver, Indianapolis, and Philadelphia), the winter sunlight isnât strong enough to promote vitamin D formation.