Although considered essential, histidine use in adult physiology remains quite limited. This amino acid is often referred to as “semi-, or conditionally essential.” Adults, seemingly, never need to supplement their diets with histidine due to the manufacturing process taking place in the liver from other amino acids. However, children and infants are the exception. This is due to the importance of proper growth and development. In this demographic (infants and children) histidine is considered essential and must be obtained from the diet.
Histidine is one of the most common of all naturally occurring amino acids. It is found in large concentrations in skeletal muscle. The dipeptides found in muscle (anserine and carnosine) are both comprised of one part L-Histamine, and one part beta-alanine.
Histidine’s primary responsibility lies within its ability to aid the human body with the growth and repair of tissues. It also serves as the primary amino acid responsible for maintaining the myelin sheaths that surround and protect delicate nerve cells. This amino acid is also a significant component in many fundamental human metabolic processes. It aids in the production of red and white blood cells, increases sexual functioning in adults, helps to regulate and stabilize blood pressure, and assists in ridding the body of (metallic) toxins via the circulatory system.
Histidine is also the precursor to histamine biosynthesis. Histamine is the compound released by the immune system during an allergic or inflammatory reaction.
Histidine is found in large concentrations in both animal and vegetable proteins. The best sources include; dairy products, meats, poultry, fish, wheat, and rye. Serving sizes below are based upon 100 grams of a given food source and are expressed in milligrams, representing the amount of histidine contained.
|Nut and Seed Products|
|2403||Seeds, sunflower seed flour, partially defatted|
|2157||Seeds, sesame flour, low-fat|
|1796||Seeds, cottonseed flour, low fat (glandless)|
|Legumes and Legume Products|
|2300||Soy protein isolate|
|1580||Soy protein concentrate, produced by alcohol extraction|
|1580||Soy protein concentrate, produced by acid wash|
|1390||Tofu, dried-frozen (koyadofu)|
|1390||Tofu, dried-frozen (koyadofu), prepared with calcium sulfate|
|1320||Peanut flour, defatted|
|1270||Soy flour, defatted|
|1260||Soy flour, low-fat|
|Finfish and Shellfish Products|
|1850||Fish, cod, Atlantic, dried and salted|
|1390||Pork, cured, bacon, cooked, broiled, pan-fried or roasted, reduced sodium|
|1340||Pork, cured, bacon, cooked, baked|
|1290||Pork, fresh, loin, center loin (chops), bone-in, separable lean only, cooked, pan-fried|
|1270||Pork, fresh, loin, top loin (chops), boneless, separable lean and fat, cooked, braised|
|1240||Pork, fresh, loin, sirloin (chops), boneless, separable lean only, cooked, broiled|
|1240||Pork, fresh, shoulder, blade, boston (steaks), separable lean only, cooked, braised|
|1240||Pork, fresh, loin, top loin (chops), boneless, separable lean and fat, cooked, pan-broiled|
|Lamb, Veal, and Game Products|
|1490||Game meat, deer, cooked, roasted|
|1400||Game meat, antelope, cooked, roasted|
|1330||Veal, leg (top round), separable lean only, cooked, braised|
|1270||Veal, cubed for stew (leg and shoulder), separable lean only, cooked, braised|
|1250||Veal, rib, separable lean only, cooked, braised|
|Dairy and Egg Products|
|1830||Egg, white, dried|
|1750||Egg, white, dried, flakes, glucose reduced|
|1610||Cheese, parmesan, shredded|
Suplementally, histamine has been used for a multitude of diseases and conditions affecting the human body. Clinical application and studies of histidine have conducted for use in the treatments of cardiovascular disease, anemia, allergic disorders, and sexual health.
As mentioned, histidine is a needed nutrient in the formation of the immune system. In conjunction with the B-vitamin compounds B3 and B6, supplemental forms of histidine will be biosynthesized into histamine. Histamine is known to produce certain anti-allergy and and anti-inflammatory reactions, but unknown to many, may be equally beneficial in enhancing sexual arousal.  The supplementation of histidine may ultimately assist in the lengthening of orgasms and provide for a more intense and enjoyable sexual experience.
Histamine is also significant in the production of stomach acid. Persons with a shortage of gastric juices, or individuals suffering from common indigestion, may benefit from dietary supplementation of histidine.
Individuals suffering from rheumatoid arthritis often exhibit lower levels of histidine as well. Symptoms of arthritis can often times improve with the addition of histidine into diet.  Supplemented dosages range from 1000 - 1500 milligrams taken three times daily.
Histidine also produces a hypotensive effect (lowers blood pressure) via the autonomic nervous system. It may also inhibit the transition of HIV to AIDS, act as an antioxidant from external radiation and as a chelating agent to metal; thereby improving the absorption of specific minerals. 
The U.S. National Academy of Sciences recommends that healthy people achieve .36 grams of highly bioavailable protein for each pound of bodyweight - equaling 0.8 grams of protein, per kilogram of bodyweight. Listed below are the Recommended Daily Allowances (RDAs) for the majority of amino acids, including histidine.
|Requirement - mg. per kg. of body weight|
|Amino acid||Infant 3 - 6 mo.||Child 10 - 12 yr.||Adults|
|Histidine||33||not known||not known|
|S-containing amino acids||45||22||10|
|Aromatic amino acids||132||22||16|
Although research in toxicities has not been conclusively proven, it is theorized that excessive levels of histidine may lead to certain psychological disorders; chiefly, anxiety and schizophrenia. A common trait of schizophrenics are extremely high levels of histidine throughout the body.
Deficiencies of histidine have been reported when combined with the amino acid methionine. Individuals suffering from rheumatoid arthritis have also been shown to possess inadequate levels of this particular amino acid; they may be at the greatest risk for onset of deficiency. Nerve deafness may result due to prolonged inadequacies of histidine as well.
In addition, histidinemia is an inborn error characterized by the inability to metabolize histidine, due to the deficiency of the enzyme histidase. Persons suffering from this condition usually exhibit excessive amounts of this essential amino acid in the blood and urine. Diagnosis of histidinemia is often acheived by using clinical testing procedures to determine the underlying cause of speech disorders and mental retardation.
1. Nutrition Data. “999 Foods; Highest in histidine.” (2004) http://www.pdrhealth.com/drug_info/nmdrugprofiles/herbaldrugs/101840.shtml
2. Balch, Phyllis A., James F. “Amino Acids.” Prescription for Nutritional Healing. Ed. Amy C. Tecklenberg. New York, NY: Penguin Putnam Inc., 3rd Ed. 2000. 42-53.
3. Gerber DA, Gerber MG. Specificity of a low free histidine concentration for rheumatoid arthritis. J Chronic Dis 1977; 30:115-27.
4. Zest for life information page. “RDA of amino acids.” (1999-2003) http://www.pdrhealth.com/drug_info/nmdrugprofiles/herbaldrugs/101840.shtml (14 Sept. 2004).