Principles of protein requirement
Proteins are organic substances that consist of chains of amino acids varying in length, meaning every protein has a distinguishing sequence of amino acids.
9 out of 21 different amino acids are essential, meaning that the body itself cannot produce them.
Because of the fact that proteins have different functions in organisms, they are known as the building blocks of life:
- Building of endogenous proteins:
- Protein structures are components of muscle, skin, membranes, and connective tissue
- Hormones like insulin, growth hormones etc.
- Enzymes, carrier proteins, antibodies
- Amino acids provide 4kcal/g of protein and can be used for the production of energy
- Positive effects for bone density.
Essential amino acids:
Isoleucine, Leucine, Lysine, Methionine, Phenylalanine, Threonine, Tryptophan, Valine, Histidine
Conditionally essential amino acids:*
Arginin, Cysteine, Glutamine, Serine, Tyrosine
Non-essential amino acids:
Alanine, Asparagine, Aspartic acid, Glutamic acid, Glycine, Proline
* Conditionally essential amino acids are important under certain circumstances (e.g. illness).
Proteins are found in plants as well as animal foods and show a high saturation effect.
Animal proteins often contain more essential amino acids than plant proteins.