5 Facts About Proteins

While you may have been told more than once to eat your protein, you may not be entirely sure what proteins are and how they contribute to your health. Proteins are a class of macronutrients, which means they should make up a large percentage of your diet. A few basic facts can fortify your knowledge about proteins and help you understand what the macronutrient does for your body.

Proteins in Your Body

Every cell in your body contains protein. The nutrient is a component of your hair, skin, bones, fingernails and major organs. Protein is also in the majority of your body fluids, with the exception of bile and urine, notes MedlinePlus. Your body regularly breaks down old cells and creates new ones during the constant growth process. Eating protein helps ensure your body contains enough protein to repair broken down cells and synthesize new cells and tissues.

Composition of Proteins

Each protein contains a varying sequence of structures called amino acids. There are 20 amino acids. Of these amino acids, 11 are nonessential, which means your body can make them so you do not have to include them in your diet. The remaining nine amino acids are essential, which means you have to get them through your diet because your body cannot make them.

The sequence of amino acids, called the amino acid profile, determines the type of protein. Proteins that contain all of the essential amino acids are categorized as complete proteins. Proteins that are missing one or more of the essential amino acids are classified as incomplete proteins.

Protein Functions

Protein performs more functions in your body than the other macronutrients. Because proteins contain calories, the proteins in your diet provide you with energy in the absence of carbohydrates. Proteins also maintain fluid balance and acid-base balance and act as transportation devices, carrying oxygen, waste products and vitamins throughout your body. Proteins are also involved in your immune system response.

Protein Food Sources

A variety of different foods contain dietary protein. Most foods from animal sources, such as meat, fish, poultry, eggs, milk and yogurt, contain complete proteins. Non-animal sources of protein, such as nuts, peanut butter, soy and beans, usually contain incomplete proteins.

Protein Needs

Your needs for protein depend on your body weight and your age. Teenagers between the ages of 14 and 18 should consume 0.85 g of protein for every 1 kg of body weight. Adults need 0.80 g of protein per 1 kg of body weight. For a 150 lb., or 68.2 kg adult, this translates to approximately 55 g of protein each day.