L-histidine is an essential amino acid and one of the 23 proteinogenic amino acids. It has an imidazole functional group, which is typical for an aromatic amino acid. It is involved in the formation of proteins and influences several of the metabolic reactions in the body.
As L-histidine is only produced in very small amounts by the body, it must predominantly be taken in through the diet. In certain cases, the synthesis of L-histidine is so limited that it can be said to be one of the essential amino acids.
Infants in particular need an additional source of L-histidine, either through breast milk, special supplements, or formula milk, as a deficiency can lead to growth problems and other conditions.
Histidine is also an essential substance for those recovering from an illness and during growth (in childhood and the teenage years). It is best to take L-histidine on an empty stomach, as it is then more effective.
An unbalanced diet or too much stress can also lead to a deficiency, which can manifest itself in growth disruptions or rheumatic arthritis in adults.
L-histidine has many vital functions within the body and is involved in the synthesis of haemoglobin, tissue repair and the strengthening of the immune system.
Foods Containing Lots of L-histidine
L-histidine is mostly contained in foods rich in protein and is exclusively produced in young plant tissues and is passed on to animals through the food chain. The effects of stress, existing chronic conditions and injuries increase the daily requirement of L-histidine; this need can often only be met through the relevant nutritional supplements.
After operations or in cases of arthritis or anaemia, the body’s need for L-histidine can rise very rapidly, so that supplementation should be considered. An undersupply can have serious consequences for children and young people, as they are still growing and a deficiency can disrupt normal growth.
Furthermore, Histidine regulates the immune defence in the body, allergic reactions and inflammatory processes, so a deficiency of L-histidine can lead to an increased tendency towards infection and the aggravation of symptoms of allergies.
In order to prevent these problems, a balanced and varied diet is needed, and consumption of the following foods can help meet the daily requirement.
Next to soya beans (around 1097mg per 100g), chicken breast fillets (around 791mg per 100g) and beef (around 678mg per 100g) are particularly good sources of L-histidine and should be built in to the diet plan wherever possible.
Wheat germs (around 643mg per 100g) and raw salmon (around 549mg per 100g) are also suitable for meeting the daily requirement.
It is important to note that, like vitamins, the actual L-histidine content of these foods is dependent on the storage conditions and preparation methods, and may differ from the standard value. Above all peas, walnuts and maize should be kept sealed and out of sunlight, as UV radiation and oxygen gradually destroy the L-histidine contained, reducing the nutritional value of these foods.
Functions of L-histidine
One of the most important characteristics of Histidine is that it can be converted into various substances, including histamine, glutamate and haemoglobin. Furthermore, it is involved in various metabolic reactions and hence ensures indirectly the oxygen supply to all the organs and tissues. It is a building block for many molecules containing iron, for example ferritin. This function is also important, as it ensures a sufficient energy supply in the cells and can detoxify the body of heavy metals through its ability to combine with them.
Other functions performed by L-histidine include the regulation of the pH-values of the blood, supporting the healing of wounds, and the regulation of growth and natural repair mechanisms. Without L-histidine, growth processes would be interrupted and a lack of this amino acid can lead to slow development and the regeneration of tissue. It is also possible that a deficiency can lead to the inflammation of the skin and mucous membranes and a slower recovery after operations or surgical procedures.
Among other things, L-histidine is also necessary for the formation of the myelin sheath, which surrounds all nerve cells and protects them from damage, and can be used to prevent certain degenerative conditions, such as Alzheimer’s and Parkinson’s. Moreover, this semi-essential amino acid is involved in in the synthesis of red and white blood cells, and so influences the activity of the immune system, as leukocytes play a large role in combating pathogens.
Finally, L-histidine can protect the body from radiation damage, by binding itself to the damaging molecules, therefore eliminating them. For this reason, a specially-designed preparation containing L-histidine can be administered before medical treatment where ionising radiation is involved, to protect the body from the direct and indirect effects of radiation.
Furthermore, L-histidine can have a therapeutic effect in cases of inflammation and can therefore be used in the treatment of arthritis and to help reduce the symptoms of allergies.
The Medical Uses of L-histidine
The preventative and therapeutic potential of L-histidine has not yet been fully explored, although several studies have already been carried out which have proven the effectiveness of this vital substance in medical treatment.
L-histidine Can Lower Blood Pressure
The discovery that this amino acid can lower the blood pressure was a particularly important step 1. As L-histidine relaxes the blood vessels, it can get rid of hypertension and help prevent cardiovascular conditions, such as arteriosclerosis and heart attacks. Researchers also proved that the daily consumption of a nutritional supplement containing L-histidine can reduce the risk of cardiovascular conditions by up to 60.9%.
A further area where the use of L-histidine supplements is important is the treatment of chronic kidney failure, which is particularly common among the elderly. A low concentration of L-histidine in the blood plasma increases the inflammatory activity of the body and leads to a rise in oxidative stress, so supplementation of L-histidine is directly associated with a reduced mortality rate. 2
Furthermore, it has recently been discovered that L-histidine, in combination with zinc (which is made easier to absorb into the body by the amino acid), can be effective against colds. A study was carried out with over 40 participants to investigate to what extent the intake of zinc and L-histidine can minimise the duration of a viral or bacterial infection. The researchers came to the conclusions that the consumption of both these vital substances together shortens the length of a common cold by an average of 3.6 days. 3
L-histidine plays a role in the regulation of growth and contributes to the formation of blood cells. Children in particular should ensure a sufficient supply of this vital substance, as a deficiency can lead to growth problems. Furthermore, nutritional supplements containing L-histidine are very helpful during the recovery process after an operation or injury, as it supports the healing process and encourages the regeneration of tissue. This semi-essential amino acid has also already proven its worth in the treatment of certain illnesses and can, among other things, reduce the severity of kidney failure and help prevent heart attacks.
- “Tuttle KR et al.: Dietary amino acids and blood pressure: A cohort study of patients with cardiovascular disease; AM J Kidney Dis, 2012 Feb 28″ ↩
- Makoto Watanabe et al.: Consequences of low plasma histidine in chronic kidney disease patients: associations with inflammation, oxidative stress, and mortality; American Journal of Clinical Nutrition; Vol. 87. No. 6, 1860-1866, June 2008 ↩
- “Prasad As et al.: Duration of symptoms and plasma cytokine levels in patients with the common cold treated with zinc acetate. Ann Intern Med. 2000; 133 ↩