Glutamate is intimately linked to addictive behaviors.
See the following link about how brain neurotransmitters like Glutamate and
Gamma Amino Butyric Acid (GABA) are affected by alcohol and other drugs linked to substance abuse:
http://gslc.genetics.utah.edu/units/addiction/reward/pathways.cfm
Glutamate in its free state - as found in MSG, stimulates the NMDA (N-Methyl D-Aspartate) receptors
in the brain. These receptors are currently being investigated for their role in
Long Term Depression.
Glutamate and GABA are yin and yang when it comes to
brain neurotransmitters. They must be in balance for things to work
properly. The body has a chemical feedback loop to make sure of this.
GABA, is created from
excess glutamate in the body, by the enzyme Glutamic Acid Decarboxylase
(GAD). GABA has the opposite effect of MSG and glutamate. It is
calming. GABA fits the same receptors in the
brain as valium and so may have an addictive effect.
GABA is the body's natural version of valium.
Excess excitatory glutamate SHOULD be turned into calming GABA, however, in
some individuals, an imbalance compels them to act to swing the balance
back. That means seeking out substances that have the same effect as GABA.
Not everyone can easily get rid of excess Glutamate
from MSG and these folks may be at risk of addictive behaviors due to a GABA
deficiency. It should be noted that Type I diabetics often have
antibodies against GAD, so they are already at risk of not being able to
make GABA properly.
Taurine, made from
the amino acid cysteine, which is adversely affected by glutamate, has shown
some promise in treating drug addiction. Taurine is
also a neurotransmitter that has a CNS-calming effect like GABA.