Eating protein is essential to human health because protein is one of the key human nutrients, along with fat and carbohydrates. The body uses protein to build cells, regulate the production of enzymes and hormones, maintain the fluid balance between cells, and create energy. Eating protein can help keep the body strong and can regulate important metabolic functions. Eating too much protein, however, may cause health problems.
Protein is made up of the 20 essential amino acids that form the molecular building blocks of the human body. The tissues of the human body are generally subject to a continuous process of depletion and renewal. The body typically uses protein to build and renew every type of cell, including those that make up bones, muscles, organs, and connective tissues.
Eating protein can help the human body manufacture essential enzymes and hormones. Hormones such as insulin, which regulates blood glucose levels, are generally made up of the essential amino acids found in protein. Enzymes are molecules of protein that allow biological chemical reactions to occur. Enzymes act as chemical catalysts to the reactions that occur within the body during digestion and other metabolic processes. Eating protein helps keep enzyme and hormone levels normal to prevent metabolic and endocrine disorders.
Protein also helps the human body maintain an appropriate fluid balance in and between cells. Blood protein molecules called albumins and globulins help create the pressure that typically regulates the flow of blood into and out of capillary regions, where blood pressure is often lower.
The human body generally uses carbohydrates and fats for energy, rather than protein. The human body typically uses protein for energy only if dietary sources of fats and carbohydrates are low. When the body uses protein for energy, tissue maintenance and other crucial bodily functions usually suffer. That's why a diet high in protein but low in carbohydrates and fat can be dangerous.
The human body can usually store excess carbohydrates and fat for later use, but it can't store protein. The human body typically breaks protein down into its component parts, the essential amino acids. The human body usually strips nitrogen from any excess amino acids in the blood. This nitrogen can build up in the kidneys and liver, damaging these organs and contributing to liver and kidney disease. Eating protein in excessive amounts may also contribute to osteoporosis, heart disease, cancer, and kidney stones.