Source of life Essential amino acids Balance of amino acids

Amino acids are the oldest nutrients that have existed on earth. They have been used as the source of life over the period from primordial life to the present stage of evolution marked by the appearance of man.

	Water accounts for about 60% of the human body. About a half of the remaining part consists of amino acids (including proteins). Amino acids perform various important functions for the body and serve as the materials for the body's cells, hormones, and enzymes.

Proteins are made up of 20 kinds of amino acids. Of these 20 kinds, 9 must be taken from food since they are not synthesized in the body. Therefore, they are called "essential amino acids". It is necessary to compensate these "essential amino acids" from food in well-balanced, appropriate amounts.

Valine, Leucine, Isoleucine, Alanine, Arginine, Glutamine, Lysine, Aspartic acid, Glutamate, Proline, Cysteine, Threonine, Methionine, Histidine, Phenylalanine, Tyrosine, Tryptophan, Asparagine, Glycine, Serine

The preferable balance of amino acids we should take is defined by international institutions (FAO/WHO/UNU). In accordance with these patterns, we need to supplement the relatively least amino acid, which is called the limiting amino acid. Generally, animal proteins such as egg proteins are known to have high amino acid scores, while plant proteins such as wheat and corn have low amino acid scores.

	Egg proteins have an amino acid score of 100%! The amino acid balance of egg is said to be the best of all proteins. Amino acid scores for wheat proteins and polished rice are 42% and 61%, respectively. Lysine is known to be the most insufficient essential amino acid for both foods.