Proteins play a variety of important roles in the body. They are needed for the growth, maintenance, and repair of cells, and for the production of enzymes, hormones, and the chemicals that control our heredity. Proteins are the main components of muscle tissue and are important to the internal organs, bones, skin, and hair. They also play a role in the working of the memory and the transmission of impulses through the nerves.
Proteins are important regulators – involved in maintaining the body’s osmotic pressure and fluid balance, its acidity (PH), blood pressure, growth, blood-sugar level, and metabolism. Some proteins act as antibodies, some enable the blood to clot, and others transport nutrients and oxygen throughout the bloodstream. Proteins also make up all enzymes, the catalytic substances that control almost all of the chemical processes in our bodies.
Proteins can be a source of energy, supplying the body with 4 calories per gram of protein. When the body does not get enough carbohydrate or fat to meet its energy need, proteins will be broken down to supply these calories. However, proteins that are used for energy are not available for other vital functions that can be carried out only by proteins. This energy-protein relationship explains why a diet that supplies adequate calories from carbohydratesor fats is considered to be protein sparing.
On the other hand, when there is more protein in the body than is needed, this energy must be stored. The body has no provisions for storing extra amounts of proteins in their original form, so protein molecules are altered by the body in order to be stored as fat.