What is protein?

Protein is one of the three macronutrients essential for the human body, alongside carbohydrates and fats. Proteins are large, complex molecules made up of smaller units called amino acids. Amino acids are often referred to as the “building blocks” of proteins.

The human body requires protein for a variety of vital functions, making it an essential nutrient for growth, repair, and maintenance of tissues. Here are some key roles of proteins in the body:

Building and Repairing Tissues: Proteins play a crucial role in building and repairing tissues, including muscles, bones, skin, hair, and nails. After physical activities or injuries, proteins aid in the repair and recovery of damaged tissues.

Enzymes: Many enzymes, which are proteins, act as catalysts in various chemical reactions that occur within the body. Enzymes are essential for processes such as digestion, metabolism, and cellular energy production.

Hormones: Certain proteins function as hormones, which are chemical messengers that regulate various physiological processes, including growth, metabolism, and reproductive functions.

Transport and Storage: Some proteins help transport molecules, such as oxygen in the blood (hemoglobin) and nutrients within cells. Other proteins serve as storage reservoirs for important minerals and nutrients.

Immune System Function: Antibodies are specialized proteins that play a vital role in the body’s immune system, helping to identify and neutralize harmful substances like bacteria and viruses.

Source of Energy: While carbohydrates and fats are the primary sources of energy, the body can use proteins for energy when necessary. However, the body typically prefers to use carbohydrates and fats for fuel, preserving proteins for their other critical functions.
Proteins are composed of different combinations of 20 standard amino acids. The specific sequence and arrangement of amino acids determine the unique structure and function of each protein in the body.


Dietary sources of protein include animal-based foods like meat, poultry, fish, eggs, and dairy products, as well as plant-based sources like legumes, nuts, seeds, and certain grains. Consuming a variety of protein sources ensures that the body receives all essential amino acids required for proper health and function. Protein intake is essential for people of all ages and is particularly important for growing children, athletes, and individuals recovering from injuries or illnesses.