Everyone has heard that milk is good for the bones, and that is because milk is one of the primary sources of vitamin D in the American diet, as well as a good source of calcium.However, adequate calcium and vitamin D intake is not enough to prevent osteoporosis.hether milk is actually a healthy choice depends on the individual and type of milk being consumed. Some milk is high in protein, low in added sugar and free of unnecessary additives, but there are also flavored milks that have just as much sugar as a can of soda.