Histidine

What is histidine?

Histidine is an essential amino acid ^[1]. In foods, histidine is incorporated into proteins.

Histidine abbreviation (symbol): His

Histidine Functions in the Human Body

Histidine is:

• A building block of proteins
• A precursor of the neurotransmitter histamine ^[4] and, together with beta-alanine, a precursor of the dipeptide carnosine ^[7].
• A glucogenic amino acid — it can be converted into glucose ^[8]
• A basic (pH >7) amino acids (together with arginine and lysine) ^[5]

Foods High in Histidine

• ANIMAL FOODS: pork, beef, chicken, turkey, fish, cheese ^[9]
• PLANT FOODS: legumes ^[9]

Foods low in histidine: wheat, fruits, vegetables ^[9]

Histidine Supplements

Oral L-histidine supplements are available without prescription (over-the-counter).

Histidine is also used as a chelator (binder) in zinc and copper supplements.

Possible Histidine Health Benefits

Histidine is POSSIBLY INEFFECTIVE in ^[2] :

• Relieving pain in rheumatoid arthritis
• Improving anemia associated with a kidney disease or hemodialysis

There is INSUFFICIENT EVIDENCE about the effectiveness of histidine supplements in the prevention or treatment of anemia due to folate deficiency ^[6], allergies and ulcers ^[2] or in increasing muscle power or athletic performance.

Histidine Safety: Side Effects, Toxicity

Histidine supplements, when taken by mouth in recommended doses, are POSSIBLY SAFE for most people ^[2].

Side effects of doses up to 4 grams per day are not known ^[2].

During Pregnancy

Not enough studies have been done about the safety of histidine supplements during pregnancy and breastfeeding, so women in these periods should avoid them ^[2].

Individuals with folic acid deficiency should also avoid histidine supplements because they can cause accumulation of the metabolite formiminoglutamic acid in the body ^[2].

Histidinemia

Histidinemia is a rare inherited disorder with increased levels of histidine in the blood and urine due to lack of the enzyme that breaks down histidine. The affected individuals usually have no symptoms and do not need any diet restrictions or therapy ^[3].