Histidine is classed as a 'semi-essential' amino acid, because, even though adults are able to synthesize it and do not require it to be supplied through nutritional sources, children and infants (as well as adults with specific medical conditions) do require dietary or supplementary histidine. This is particularly true during periods of rapid growth, when deficiency is most likely to occur.
Histidine helps maintain healthy tissues and nerve responses. It regulates blood pressure – specifically, histidine can lower high blood pressure – and it helps the body elminate toxins through the circulatory system. As mentioned, it boosts sexual functioning.
Histidine is also involved in immune system formation, because it helps form the white blood cells which are the primary immune response. Histidine is likewise invovled in the formation of stomach juices needed to digest and metabolize food. Furthermore, histidine acts as an antioxidant, particularly in cases where one has been exposed to radiation. Histidine supplementation has been used to successfully treat a range of conditions, including cardiovascular disease, anemia, and allergic disorders. Conversely, the latter two conditions, as well as rheumatoid arthritis and deafness due to nerve damage, sometimes occur as a result of histidine deficiency, and histidine supplementation might be used to successfully treat these conditions.
Histidine is found in a variety of animal and vegetable sources, including most meats, poultry, and dairy, as well as wheat and rye.
The recommended supplement dosage of histidine is 1000 – 1500 milligrams taken three times a day, or a total of 3000 -4500 milligrams per day, depending on body weight and overall health.
References (1) Dunaev, V., et al., "Effect of Malic Acid Salts on Physical Working Capacity and its Restoration After Exhausting Muscular Work," Farmakol Toksikol 51.3 (1988) : 21-5.
