Calcium
Milk is rich in calcium. Milk and milk products, such as cheese, are in fact the main source of calcium in the western diet. Calcium is necessary both to build and maintain bones and teeth. In addition, calcium is indispensable for the proper functioning of muscles and the nervous system.
If you use alcohol, caffeine and salt, your body loses calcium and you need to increase your calcium intake. Natural milk calcium, incidentally, is not only found in dairy products but also in some calcium preparations.
Read more about the nutritional value of milk