Certain histidine compounds e.g. carnosine, anserine and ergothionine are found in the blood and tissues. Carnosine is beta-alanylhistidine and anserine is beta-alanyl-1-methylhistidine. These two are found in the muscles. Ergothionine is found in the red blood corpuscles in large amount. It is not synthesized in the body and exclusively comes from dietary sources.
Sources of histidine
Important sources of histidine are dairy, meat, poultry and fish as well as rice, wheat and rye
Abnormalities of histidine metabolism
Two genetic disorders of this amino acid metabolism have been noted:
- Imidazole amino aciduria: In this condition large amounts of carnosine and anserine as well as histidine and 1-methyl histidine have been observed to be excreted through urine together with a condition of cerebromacular degeneration.
- Histidinemia: The defect is due to hypoactivity of the enzyme histidase present in the liver, interfering with the normal degradation of histidine. Retardation of development of speech might take place in such disease.
Benefits of histidine
Histidine is also a precursor of histamine, a compound released by immune system cells during an allergic reaction.
It is needed for growth and for the repair of tissue, as well as the maintenance of the myelin sheaths that act as protector for nerve cells.
It is also required for the synthesis of both red and white blood cells, and helps to protect the body from damage caused by radiation and in removing heavy metals from the body.
In the stomach, histidine is also helpful in producing gastric juices, and people with deficiency of gastric juices or suffering from indigestion, may also benefit from this nutrient.
Histidine is also used for sexual arousal, functioning and enjoyment. . By and large it is histamines that regulate ejaculations and orgasms. Men suffering from premature ejaculations often show increased histamine activity. They may be helped by an amino acid, which counteracts the formation of histamine from histidine, or the activity of histamine, namely methionine.
It is thought that histidine may be beneficial to people suffering from arthritis and nerve deafness. Histidine is used as a supplement for sufferers of rheumatoid arthritis, since it has been shown that in these patients, histidine levels are low. And last not least, histidine is, like many other amino acids, important for growth and general tissue repair.
Any important deficiency symptom is not known but it is reported that an increase in the intake of this nutrient helps with the lengthening of orgasms and also more intense sexual enjoyment.
Symptoms of high intake
There are no reported side effects with histidine, but too high levels of histidine may lead to stress and mental disorders such as anxiety and people with schizophrenia have been found to have high levels of histidine.
People suffering from schizophrenia or bipolar (manic) depression should not take a histidine supplement without the approval of their medical physician.
The daily dosage requirement is recommended as 8-10 mg per day per kilogram of body weight.
Some important facts about this amino acid
Histidine is an essential amino acid during infancy, and its synthetic pathways in older children and adults are not well understood. According to studies the clinical signs of a lack of the enzyme, which acts in the metabolism of histadine can include, impaired speech, growth retardation or mental retardation. However, whether these findings are actually related to lack of histidine is unclear since children who are deficient in histidine can be completely normal.
Too much histidine will actually cause constipation, and this is overcome by taking zinc and GLA in the form of primrose, borage, or black current oil.
Men and women having difficulties achieving orgasms may be helped by histidine supplementation, as this may result in increased histamine levels in the sexual tract, which in turn may make orgasms and ejaculations easier.