Histidine is an essential amino acid.
The molecular formula of histidine is C6H9N3O2
Amino acids generally are explained further in the column on the rightin further detail below. Briefly, there are two types of amino acid:
- Those that can be synthesized by the body itself (non-essential amino acids), and
- those that, although necessary for the healthy growth or maintenance of the body, cannot be produced by the body itself.
This second type of amino acids are called essential amino acids, and are also referred to as indispensible amino acids in some textbooks.
Histidine is one of those amino acids that are necessary and cannot be produced within the body. Therefore it is an essential amino acid, meaning that it is an essential part of a healthy diet.
Histidine is used by the body to produce histamine, which is involved in a wide range of physiological processes, including:
- dilation of blood vessels
- contraction of smooth muscle
- anaphylactic reactions
- allergic conditions, and
Note that antihistamines are sometimes prescribed to treat or mediate inflammation, infections, and allergies.
For further information about amino acids in general, see Amino Acids.