Protein 101

What is an amino acid?

Amino acids are the smallest molecular components that makes up proteins. Amino acids are made up of carbon, nitrogen, hydrogen, and oxygen atoms. In addition to these atoms, some amino acids (methionine and cysteine) also contain sulfur. There are twenty primary amino acids that are found in proteins, nine of which are essential, meaning your body can't produce them and are thus obtained through the diet.

Amino acids have many benefits including:

  • Build and repair muscles and bones
  • Repair of body cells
  • Provide a source of energy
  • Regulate various processes in the body related to metabolism

What are essential amino acids?

When the diet is deficient in some amino acids, a healthy human body can synthesize its own amino acids from other nutrients supplied to it. However, nine of the twenty amino acids cannot be synthesized by the human body. These amino acids must be supplied in the diet to avoid malnutrition. Therefore, these amino are called essential amino acids. The essential amino acids include: valine, leucine, isoleucine, threonine, methionine, phenylalanine, histidine, tryptophan, and lysine. Histidine is considered essential only for infants and not for adults.

What is protein?

Amino acids are linked together (like beads in a chain) via amide bonds, also called peptide bonds, to form proteins. All proteins are made up of the twenty primary amino acids, in various combinations. A protein molecule can have thousands of amino acids in different combinations, thereby giving the proteins unique properties.

Are some protein sources better than others?

The quality of protein varies. High-quality, complete protein sources include animal-based proteins. These proteins contain all nine essential amino acids the body needs to build and maintain muscle and to function well. Protein found in most plant foods is considered incomplete protein because it lacks some of the essential amino acids needed daily. Soy proteins are the exception to this and are considered complete proteins based on their amino acid profile.

Protein Quality Comparison Chart (Adobe pdf 13kb) provides a comparison of whey protein and other protein sources.