Milk is most closely associated with the mineral calcium, which you need to maintain strong bones and teeth. However, milk is a rich source of protein as well. According to the National Dairy Council, 1 cup of milk -– which is defined by the Dietary Guidelines for Americans as a single serving -– offers an abundance of protein, vitamin D and other essential nutrients you need for good health.
Your Need for Protein
Protein makes up every part of your body -– tissues, cells and organs, according to the Centers for Disease Control and Prevention. The protein in your body breaks down and continually needs to be replaced. The protein in the food you eat is made up of amino acids, of which there are 20. Your body can manufacture some of these amino acids itself, but others must be supplied by food sources. These are called essential amino acids because it's essential that you get them from your diet.
Protein in Milk
According to the U.S. Department of Agriculture's National Nutrient Database, 1 cup of nonfat milk contains 8.26 g of protein. The National Dairy Council states that this gives you 16 percent of your Daily Value, or DV, for protein. As an animal food, milk is considered a source of complete protein, or "high quality protein," which gives you all the essential amino acids you need.
Other Milk Benefits
One serving of milk is also rich in 8 other essential nutrients. One cup of milk provides 25 percent or more of your DV for phosphorous, riboflavin, vitamin D and calcium; and between 10 and 25 percent of your DV for niacin, vitamins A and B and potassium.
According to the USDA's Food Pyramid, adults need 3 cups of milk or milk products each day; children between the ages of 2 and 8 need 2 cups. To get enough servings from the milk group, the USDA suggests drinking reduced fat or nonfat skim milk with meals or adding it to oatmeal and condensed soups in place of water. Reduced fat or nonfat milk is recommended for adults; if you're accustomed to drinking whole milk, transition to 2 percent milk, then to 1 percent milk until you finally acquire a taste for milk that's completely fat-free.
Milk for Health
Low-fat milk and low-fat chocolate milk are better for athletes than sports drinks, note Mayo Clinic nutritionists Katherine Zeratsky and Jennifer Nelson. A small number of studies show that the carbohydrates in milk, as well as its protein -– found in the whey and casein -– are better for muscle building, as well as muscle repair, after strenuous activity. If a cup of milk doesn't tempt your palate as a protein-rich snack, try unsweetened yogurt, which makes the Center for Science in the Public Interest's list of "Best Foods." Not only is yogurt a valuable source of protein, it also contains essential nutrients such as potassium, calcium and vitamin B.