Whole milk is an excellent source of calcium, protein and Vitamin D. Its fat content gives it a higher calorie count than reduced-fat or skim milk.
All milk contains 113 milligrams of calcium and eight grams of protein per eight-ounce serving, regardless of fat content. Calcium maintains the strength of teeth and bones. It is also essential to blood clotting, maintaining stable blood pressure and brain function, releasing neurotransmitters and contracting muscles. Only 1 percent of calcium in the body is outside the bones, but this tiny amount is so crucial to the body's proper functioning that the body will rob its bones of calcium to maintain the proper level in other tissues. Protein maintains muscle mass, participates in many crucial enzyme reactions and plays a key role in transporting oxygen in the body.
Milk also provides 40 international units of Vitamin D per eight-ounce serving. Vitamin D promotes bone growth and development and helps prevent osteoporosis. Research suggests that low levels of Vitamin D may increase the risks of developing Type 1 diabetes, high blood pressure, muscle and bone pain and some forms of cancer. In addition, milk contains tryptophan, an amino acid that plays a role in regulating mood and sleep.
Whole milk contains 3.25 percent butterfat by weight, compared to 2 percent for reduced-fat milk and none for skim milk. An eight-ounce glass of whole milk contains eight grams of fat, including five grams of saturated fat.