Protein: Everything you need to know about the body-building nutrient

Protein is the quintessential nutrient that every cell in the human body requires for growth or repair. The antibodies that protect us from disease, the enzymes needed for digestion and metabolism, as well as hormones like insulin are all proteins. Here's everything you need to know about how protein works and contributes to overall health.

• Cholesterol travels through the bloodstream attached to lipoproteins (fat-carrying proteins).
• Connective tissue made from protein forms the matrix of bones; chromoproteins are a combination of protein and pigments that form hemoglobin; keratin, still another type of protein, is used by the body to make hair and nails.
• The neurotransmitters that deliver messages to the brain are made from amino acids derived from dietary protein.
• The body is constantly building protein from amino acids, some of which are recycled from the body tissue that is being rebuilt. Even so, a certain amount of protein is lost through normal wear and tear and must be replaced from the diet.
• But to use this protein, the body must first break it down into its individual amino acids and then reassemble them according to instructions found in the genetic code.

• Proteins are exceedingly complex and diverse structures built of amino acids that are linked together into long chains by peptide bonds.
• There are many thousands of different proteins, but they all have a backbone of carbon atoms interlaced with nitrogen atoms. Various groupings of atoms can be attached to this backbone.
• The human body requires 20 different amino acids to build all the proteins it needs. Of these, 11 can be made in the body, but the other nine, referred to as essential amino acids, must come from the diet.
• Just as the various letters in the alphabet are joined to make words, so too are amino acids arranged in an almost infinite number of different ways to form the more than 50,000 different proteins in the body. Proteins are made up of hundreds of amino acids.
• DNA (deoxyribonucleic acid), the genetic material that is found in the nucleus of each body cell, provides the blueprint for how amino acids are arranged to form individual proteins.

With so many essential functions allotted to protein, you might assume that it should make up the bulk of the diet, but this is not the case.

• In an ideal balanced diet, only 10 to 12 percent of daily calories should come from protein.
• Healthy adults only need 0.36 grams per pound (0.8 grams per kilogram) of body weight of protein every day.
• The typical North American diet provides more protein than the human body needs. This does not pose a serious threat for healthy persons, but too much protein adds to the workload of the kidneys and liver. Thus, people with diseases affecting these organs are often put on a low-protein diet.

Overall, protein is an invaluable part of any balanced diet. Keep this guide in mind and contact your doctor for more information.