Protein
Proteins have different functions. We need protein to grow, to maintain our body and to build and repair muscles. Protein also yields energy. The composition of protein in milk exactly matches what our body needs.
Proteins, including those in milk, come in different types. Some have important functions within cells. The proteins called enzymes, for instance, are responsible for our metabolism: they can convert nutrients into building blocks and energy. Many proteins help cells to preserve their structure, while others serve to transport substances in or out of cells. There are also proteins (hormones) that specialise in communication between cells.
Read more about the nutritional value of milk