Histidine

Description

Histidine is a nonessential amino acid in adults, which means it is manufactured from other amino acids in their livers; it does not have to be obtained directly through the diet.

Histidine is essential in the infant for proper growth and development. Metabolism of histidine in the body produces histamine, which is involved in the inflammatory response and the production of hydrochloric acid by the stomach.

In infants less than three months old, histidine deprivation results in eczema as a form of dermatitis. This is relieved when histidine is supplemented in their existing diet. A genetic metabolism disorder seen in a few people prevents them from properly metabolizing histidine and results in the buildup of histidine in the blood. This is infrequently seen in infants and produces speech defects and mental retardation in these susceptible individuals. This is not found to be a problem in adults.

Recommended Dietary Allowances

An RDA has not been established for histidine because it is a nonessential amino acid. Therapeutic doses of histidine range between 0.5 and 20g per day. Supplementation of adults with histidine up to 30g per day for short periods of time were found to result in no ill effects.

Food Sources

Histidine is a nonessential amino acid in adults, which means it is manufactured from other amino acids in the liver; it does not have to be obtained directly through the diet.

Method of Action

Histidine can be produced in the body as a result of increased muscle protein breakdown with the conversion to 3-methyl histidine. Rheumatoid arthritis is known to be associated with low blood levels of histidine and elevated 3-methylhistidine. Some reports have shown improvement of arthritis has been seen with histidine supplementation.

Histidine supplementation to individuals with allergy or inflammatory problems can aggravate the condition due to the relationship with histidine.

References

Blackburn, G.L., Grant, J.P., Young, V.R., ed. Amino Acids Metabolism and Medical Applications.

Kang-Lee, Y.A. & Harper, A.E. Effect of Histidine Intake and Hepatic Histadase Activity on the Metabolism of Histidine In Vivo. J. Nutr., 107:1427-1443, 1977.

Lutz, Tews & Harper. Simulated Amino Acid Imbalance and Histidine Transport in Rat Brain Slices. Am. J. Physiol., 229:229-34, 1975.

Munro, H.N. & Crim, M.C. The Proteins and Amino Acids. Modern Nutrition in Health and Disease, eds. R.S. Goodhart & M.E. Shils, 6 ed. Philadelphia: Lea and Febiger, 1980.

Tomas, F., Ballard, F., Y Pope, L.M. Age-Dependent Changes in the Rate of Myofibrillar Protein Degradation in Human as Assessed by 3-Methylhistidine and Creatinine Excretion", Clin Sci, 56:341-6, 1979.

Young, V.R., Meguid, M., Meredith, D.E., & Bier, D.M. Recent Developments in Knowledge of Human Amino Acid Requirements. Nitrogen Metabolism in Man, eds. J.C. Waterlow & J.M.L. Stephen. London: Applied Science Pubs, 1981.