Protein is a cornerstone of human nutrition, essential for the body's growth, repair, and overall function. As one of the three main macronutrients, along with carbohydrates and fats, protein plays a critical role in building and repairing tissues, synthesizing hormones and enzymes, and supporting immune function. Composed of amino acids, protein provides the necessary building blocks for muscles, skin, organs, and various bodily functions. While the body can produce some amino acids, nine must be obtained from dietary sources, making protein intake crucial for health and development. High-quality protein sources, such as animal products, legumes, and dairy, supply these essential amino acids, making them vital components of a balanced diet.