Protein & Your Body: How Important Is Protein?

Tuesday, October 24, 2006 - 5:12pm

By John Messmer, MD

Most people understand protein is a necessary component of a healthy diet. But how many people can say they know how much to eat? Two questions arise when planning a balanced diet that includes protein, namely:

  • What protein foods should we eat?
  • How much protein do we need?

Our bodies are composed of protein

Protein is a vital part of our bodies. The most obvious proteins most of us would recognize are our muscles. Muscle tissue consists of two proteins, actin and myosin, that interact with each other to make muscle a tissue which contracts or shortens. Muscles attached to bone allow us to move. Our hearts pump blood by the action of specialized muscles. Other muscles move food through our intestines.

Most of our bodies’ proteins are structural. Although bone is predominantly calcium, the mineral is held together in a composite made up of protein. Nerves are mostly fatty compounds, but protein is the framework which holds nerves together. Blood vessels, our organs, and our skin all have structural proteins. As we age, collagen (a supporting protein in our skin) breaks down particularly from sun exposure. Lacking the structural support, our skin wrinkles and sags and is more sensitive to trauma.

Enzymes are special proteins that cause various chemical reactions to occur. Enzymes are found in various forms and with many different functions in our cells. Digestion itself requires protein enzymes made in the cells of our digestive organs. Saliva has an enzyme to digest starches and the stomach makes enzymes that help digest the proteins we eat.

Protein helps our bodies function properly

Many of our specialized bodily functions occur because of proteins that interact in chemical reactions in our blood. Blood clotting is dependent on many proteins working together in a complex series of reactions. Our immune systems use sophisticated proteins called antibodies in cooperation with supporting protein agents to keep us safe from harmful infections and to protect us from cancer. Even our DNA uses proteins to reproduce and synthesize more DNA and to carry out the instructions encoded in the DNA to make other cellular materials, including more proteins.

An essential protein and a major component of blood is albumin. This critical protein helps us keep just the right amount of water inside our arteries and veins. Without it, we would either swell or shrivel depending on what we have eaten and our environmental conditions. Gravity would cause fluid to pool in our legs, swelling them to many times normal size if it were not for the albumin in our blood.

Protein contains essential amino acids

Proteins are large molecules made up of smaller chemicals called amino acids. Humans need 20 different amino acids in order to produce all the proteins in our bodies. We can synthesize 10 of the amino acids, but the other 10 either cannot be made or not made in a sufficient quantity to be of any use. These 10 “essential” amino acids which must be obtained from food are: threonine, lysine, methionine, arginine, valine, phenylalanine, leucine, tryptophan, isoleucine and histidine. The 10 we can make are glycine, alanine, serine, cysteine, aspartic acid, glutamic acid, asparagine, glutamine, tyrosine and proline.

Protein is such an important part of our bodies that it pays to take it seriously. We need the right amount and the correct kinds of protein to function at our best. A balanced diet will meet all our protein needs.

For more information on the recommended daily intake of protein see the following article from Pay Attention to Protein Intake.