What is the primary function of proteins in the body?

Proteins serve several essential functions in the body, but their primary role is building and repairing tissues. This includes the creation of new cells and the maintenance of existing ones, ensuring that tissues such as muscles, skin, and organs remain healthy and functional. Proteins are made up of amino acids, which are the building blocks that contribute to muscle growth, immune response, enzyme production, and the synthesis of hormones.

While proteins can indeed be utilized as an energy source, particularly when carbohydrate and fat stores are insufficient, this is not their main function. Instead, their critical role in tissue repair and growth highlights their importance in overall health, especially in recovery from injury, growth during childhood, and muscle maintenance in adults. The other options, while related to functions of the body, do not align with the primary purpose that proteins serve.