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Glutamic Acid

What is glutamic acid?

Glutamic acid is a nonessential amino acid [1]. It can be produced in your body from other amino acids, so you do not need to get it from foods in order to be healthy. Glutamates are salts of glutamic acid.

In foods, glutamic acid is incorporated into proteins.

Glutamic acid abbreviation (symbol): Glu

Glutamic Acid Functions in the Human Body

Glutamic acid is [2]:

  • A building block of proteins
  • A glucogenic amino acid — it can be converted to glucose [3]
  • An acidic amino acid [5]
  • A stimulant neurotransmitter in the brain
  • A precursor of the inhibitory neurotransmitter gamma-aminobutyric acid (GABA)
  • A precursor of other amino acids: glutamine, proline

Foods High in Glutamic Acid

  • ANIMAL FOODS: meat, fish, cheese
  • PLANT FOODS: legumes

Foods low in glutamic acid: fruits, vegetables

Glutamic Acid as a Food Additive

Glutamic acid and its salts can be added to foods as flavor enhancers that give foods an umami taste (savory taste called “the fifth taste”):

  • Glutamic acid (in the European Union labeled as the E-number E620). It can be obtained by bacterial fermentation of molasses, gluten, soy protein or other vegetable proteins.
  • Monosodium glutamate (MSG) (E621)
  • Potassium glutamate (E622)
  • Calcium diglutamate (E623)
  • Monoammonium glutamate (E624)
  • Magnesium diglutamate (E625)

Monosodium Glutamate (MSG)

Monosodium glutamate (MSG) is a food additive used as flavor enhancer, especially in Chinese foods. In the European Union it is labeled as the E-number E621. It is produced from molasses and other vegetable sources by fermentation by the bacteria Corynebacterium glutamicus.

Many side effects of monosodium glutamate collectively called “Chinese restaurant syndrome” or “MSG symptom complex” have been reported, but none of them has been scientifically proven: dry mouth, numbness, weakness, palpitations, headache, migraines, “hangover effect”, asthmatic effect and so on [6].

Glutamic Acid Supplements

Nonprescription (over-the-counter) L-glutamic acid oral supplements are available.

Glutamic Acid (Glutamate) Health Benefits

Glutamate hardly crosses the blood-brain barrier, so dietary or supplemental glutamic acid is not a good source of energy for brain; brain can produce its own glutamic acid, though [4].

There seems to be NO EVIDENCE about the effectiveness of glutamic acid supplements the prevention or treatment of alcohol withdrawal, attention deficit hyperactivity syndrome (ADHD), epilepsy, hypoglycemic coma, kidney stones, mental retardation, muscular dystrophy, Parkinson’s disease, prostate cancer or benign prostatic hypertrophy or ulcers, or in improving alertness, memory or athletic performance.

Glutamic Acid Safety: Side Effects, Toxicity

Side effect. Glutamic acid may, according to certain producer’s information leaflets, cause headache and neurological problems.

Individuals with liver or kidney problems should speak with their doctors before using glutamic acid supplements.

  1. Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids (Macronutrients) ( 2005 ) /10 Protein and Amino Acids  National Academic Press
  2. L-glutamic acid  PubChem
  3. Amino acid  ChemPep
  4. Hawkins RA et al, 2006, Structure of the Blood–Brain Barrier and Its Role in the Transport of Amino Acids  The Journal of Nutrition
  5. Acidic and basic amino acids  University of Wisconsin–Madison
  6. Freeman M, 2006, Reconsidering the effects of monosodium glutamate: a literature review  PubMed

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