Protein is an essential macronutrient, but not all food sources of protein are created equal, and you may not need as much as you think. Learn the basics about protein and shaping your diet with healthy protein foods. You also use protein to make enzymes, hormones, and other body chemicals. Protein is an important building block of bones, muscles, cartilage, skin, and blood. Your body needs protein to stay healthy and work the way it should. More than 10,000 types are found in everything from your organs to your muscles and tissues to your bones, skin, and hair. Protein is an important part of a healthy diet. Proteins are made up of chemical 'building blocks' called amino acids. Your body uses amino acids to build and repair muscles and bones and to make hormones and enzymes. They can also be used as an energy source. People generally say “protein” (or “dietary protein”) when talking about nutrition and “proteins” when discussing the science of how the individual molecules work within your body. protein, highly complex substance that is present in all living organisms. Proteins are of great nutritional value and are directly involved in the chemical processes essential for life. From a nutritional perspective, the defining characteristic of protein is its amino acid composition. Protein content in foods is commonly measured based on nitrogen content, as nitrogen is a fundamental component of amino acids. Proteins are polymer chains made of amino acids linked by peptide bonds. [1] According to IUPAC, polypeptides with a molecular mass of 10,000 Da or more are classified as proteins. At times, the term 'proteins' refers to molecules with 50-100 combined amino acids. Each protein contains one or more polypeptide chain. Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Protein is essential for cell structure, immune function, and hormone synthesis, and eating enough protein can help keep you feeling full and satisfied. High protein foods include chicken and.