Milk — whether it's cow's milk, soy milk, or almond milk — provides between one-fourth and one-third of all the calcium most children and adults should have in a day. Cow's milk is also an excellent source of lean protein. It contains many other essential nutrients, including phosphorus, vitamin D, potassium, niacin, and riboflavin, important for adult and children's health. But you might not know when, how, and why milk should fit into your healthy eating plan. 

Everydayhealth.com says to check this out:

Milk Drinkers Live Longer

Despite its contributions to good nutrition, many adults often shun drinking milk. Not so fast, say researchers at the universities of Reading, Cardiff, and Bristol in the UK: Drinking milk could reduce your risk of dying from heart disease and stroke by as much as 20 percent. The researchers' analysis of 324 previous studies on milk consumption prompted them to conclude that drinking milk "provides a survival advantage."