Glutamic acid (glutamate) is an amino acid
used by the body to build proteins. Glutamate is the most common excitatory (stimulating)
neurotransmitter in the central nervous system.
Where is it found?
Sources of glutamic acid include high-protein foods, such as meat,
poultry, fish, eggs, and
dairy products. Some protein-rich plant foods also supply glutamic acid.
Glutamic acid has been
used in connection with the following conditions (refer to the
individual health concern for complete information):
Who is likely to be deficient?
Most food sources of protein supply glutamic acid, so only a person deficient in protein
would become deficient in glutamic acid.1
How much is usually taken?
Healthy people do not need to take glutamic acid as a supplement; for those who do use this
amino acid, appropriate amounts should be
determined with the consultation of a physician.
Are there any side effects or interactions?
Glutamic acid is generally free of side effects for the vast majority of people who take
it; however, people with kidney or liver
disease should not consume high intakes of amino
acids without consulting a healthcare professional. Because over stimulation of glutamate
receptors is thought to be a possible cause of certain neurological diseases (e.g.,
amyotrophic lateral sclerosis [Lou Gehrig’s disease] and epilepsy), people with a neurological disease should
consult of physician before supplementing with glutamate.
Monosodium glutamate (MSG), the form of glutamic acid that is used as a flavor enhancer,
has been reported in anecdotal studies to have a number of different adverse effects
(including headache, fatigue, and depression).
However, controlled trials have failed to confirm that MSG causes these side effects, and the
safety of this compound remains controversial.
At the time of writing, there were no well-known drug interactions
with glutamic acid.
References:1. 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.