Glutamic Acid Introduction

Glutamic Acid, or glutamate, is a stimulating (excitatory) neurotransmitter found in the human central nervous system. In men, prostate fluid also supplies varying amounts of this amino acid. Glutamic acid is a direct antecedent to the amino acid GABA, and is amongst the most common of all amino acids. It is considered nonessential in nature because of the body’s ability to manufacture it from diet and/or simpler compounds. Humans may also meet bodily requirements of glutamic acid by means of amino acid biosynthesis from, mainly, ornithine and arginine.

Essentially, glutamic acid is a building block and key component of protein and protein-related synthesis. It is equally critical in proper cell functioning throughout the body. Glutamate’s responsibilities include; the metabolism of sugars and fats, fuel for the brain, and the assistance with cognitive functioning in humans.

Glutamic acid does not enter the brain readily; and when it is does enter the brain barrier it does so in minute quantities. However, glutamic acid provides for the transportation of potassium across the protective tissues that prevent foreign substances from entering the brain. This structure in the brain is defined as the blood-brain-barrier. The blood-brain-barrier prevents many lower life forms, such as toxins, from entering the brain and disturbing the immaculate nerve cell environment.

Serving sizes below are based upon 100 grams of a given food source and are expressed in milligrams, representing the amount of glutamic acid contained. Higher protein foods, such as high protein meats and plants, supply the majority of dietary glutamic acid. [1]

Glutamic acid (glutamate) supplementation provides the body with various physiological benefit. It has been rigorously studied in clinical application for the treatment of both acute and chronic conditions. Among its most popular uses include those associated with the heart, prostate, and behavioral health.

Heart disease continues to head the list as the number one killer of adults in America. Glutamic acid may provide a protective mechanism against the deterioration of heart muscle in persons suffering from heart disease. Studies indicate that intravenous injections of glutamic acid, in the form of monosodium glutamate (MSG), have been shown to increase heart function and exercise tolerance in persons suffering from this disease. [2] Another demographic benefiting from various forms of glutamic acid supplementation includes those suffering from stable angina pectoris (the medical term for chest pain or discomfort due to coronary heart disease).

In men, glutamic acid may play an integral role in the normal functioning of the prostate. This is primarily due to the significant amount of glutamic acid found in prostate fluid. As men age the prostate gland enlarges. Doctors refer to this common enlargement as benign prostatic hyperplasia (BPH), or benign prostatic hypertrophy.

In one clinical trial, symptoms of this enlargement (BPH) were significantly improved in a group of nearly fifty men taking 780 milligrams of glutamic acid per day, for two weeks; followed by 390 milligrams for the next two and a half months. Glutamic acid was taken in combination with equal amounts of the amino acids alanine and glycine in this particular study. [3, 4]

Glutamate may also enhance certain aspects of cognitive functioning in the brain, primarily with memory and learning. Although its exact mechanism of action is not fully understood, it may also be used to correct personality disorders in adults, and also in the treatment of childhood behavioral disorders. [5] Treatments with glutamate include, and are not limited to; epilepsy, mental retardation, muscular dystrophy, and hypoglycemic coma (complication in the insulin treatment diabetes mellitus).

The administration of excessive amounts of glutamate are not recommended and may be linked to the neurological damage seen in amyotrophic lateral sclerosis (i.e. Lou Gehrig’s disease), lathyrism, and Alzheimer's disease.

An RDA (Recommended Daily Allowance) has not been established for Glutamic acid. Common dosages range from 25 to 30 milligrams per day. This amount has been labeled as ‘tolerable’ for the personal administration of glutamic acid, or glutamate-containing products.

Glutamic Acid Deficiencies

There currently is no known deficiency associated with glutamic acid. It is agreed by the medical community that only persons deficient in proteins would become deficient in glutamic acid. [7]

Glutamic Acid Toxicities

The supplementation of glutamic acid in excess (> 3 grams) has resulted in intestinal discomfort and other gastrointestinal disturbances. Symptoms associated with high intakes of this nutrient include headaches and onset of specific neurological problems.

1. Nutrition Data. “999 Foods; Highest in Glutamic Acid.” (2004)

http://www.nutritiondata.com/foods-000092000000000000000-w.html

2. Thomassen A, Nielsen TT, Bagger JP, et al. Antiischemic and metabolic effects of glutamate during pacing in patients with stable angina pectoris secondary to either coronary heart disease or syndrome X. Am J Cardiol 1991; 125:2907-15.

3. Damrau F. Benign prostatic hypertrophy: amino acid therapy for symptomatic relief. J Am Geriatr Soc 1962; 10:426-30.

4. Feinblatt HM, Gant JC. Palliative treatment of benign prostatic hypertrophy. Value of glycine-alanine-glutamic acid combination. J Maine Med Assoc 1958; 49:99-101, 124.

5. 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.

6. Zest for life information page. “RDA of amino acids.” (1999-2003) http://www.anyvitamins.com/amino-acids/rda-amino-acids.htm (14 Sept. 2004).

7. Zello GA, Wykes LF, Ball RO, et al. Recent advances in methods of assessing dietary amino acid requirements for adult humans. J Nutr 1995; 125:2907-15.