[Answering M.F.’s questions: You recently stressed that I need to
increase the levels of GABA in my body to help with my persistent anxiety. Are
there natural ways to do this through specific foods or even drinks, such as
loose leaf tea (due to its precursor l-theanine)?]
Background:
As a general rule, in promoting health I like
to stay as close as possible to letting and assisting the body in building its
own enzymes, hormones, different substances via its own machinery because of my
fear of disrupting the body’s magnificent equilibrium. This fear encompasses
different issues of feedback mechanisms, rate limiting steps, dependency
issues, etc.
Without further
ado: GABA (Gamma-amino-butyric acid) functions in
brain tissue as an inhibitory neurotransmitter by altering transmembrane
potential differences. Throughout the adult brain, where scientists have mostly
studied the roles of glutamate and GABA, it has been established that both
amino acids function primarily as signals transmitted between cells. Most of
the cells transmitting either glutamate or GABA signals are neurons. After
release, GABA diffuses a very short distance and binds to receptor proteins on
the surface of the target neuron, which are specialized for sensing either GABA
or glutamate via either glutamatergic or GABA receptors. GABA subsequently will
be taken up, or transported out by carrier proteins. The uptake process
requires energy and involves co-transport of GABA, which is neutral at physiological
pH, together with two sodium ions and one chloride ion.[3],[5] The
result of GABA stimulation of GABA receptors specifically serves to retard the
stimulatory effects of glutamate throughout the brain.
Why is it important for anxiety? All anxiogenic agents act on the
GABA-A receptor/chloride ion channel complex, implicating this neurotransmitter
system in the pathogenesis of anxiety and panic attacks.[7] As such increasing GABA
availability, and or increasing the efficiency/effect of, or sensitivity of GABA
receptors should help alleviate the feelings of anxiety.
How to
promote its availability: GABA (Gamma-amino-butyric
acid) can be formed from glutamic acid in the presence of pyridoxal
phosphate[1] (as a cofactor for glutamic
acid decarboxylase – GAD).[2] The pyridoxal phosphate
arises from vitamin B6 (pyridoxine). Therefore availability of B6 is necessary.
Don't overdo. Too much B6 has neurotoxic effects. 10 mg per day is easily
sufficient. Other factors that may promote healthy GABA metabolism would be
physiological levels of sodium and chloride (salt), in an ample fluid medium.
Practical translation: sufficient salt and water intake. Lyte-Hydrate well.
Valerian
raises GAD (glutamic acid decarboxylase) activity[4] which may raise GABA
(Gamma-amino-butyric acid) in the neuronal tissues which should have a calming
effect. The extract also contains GABA[8] which may have a direct impact on GABA
receptors.
Make sure the building block of GABA is
available (glutamic acid): All meats, poultry, fish, eggs, dairy products, and
kombu are excellent sources of glutamic acid. Some protein-rich plant foods
also serve as sources.[1]
To my knowledge only certain pharmaceuticals
(such as phenobarbitone) function as a GABA receptor modulator which enhances the
target function of said receptors.
Theanine: is an amino acid present in green tea which appears
to have stimulatory effects and inhibitory effects on glutamic acid. For calming
one would desire the inhibitory effect. How it works seems unclear to date
(5-28-12). As such I would think it would be okay to use although in this case
it is functioning more as a pharmaceutical agent and not as a building block. Theanine
is similar in molecular structure to glutamic acid and hence could be ‘pressuring’
glutamic acid and causing it to be more available for transforming into GABA. Here
I am theorizing. Then again it could be occupying glutamatergic receptors without
causing the usual excitatory activity which glutamic acid usually results in. Here
I am theorizing again.
References:
[1] Rodwell VW. Chapter 30. Conversion of Amino
Acids to Specialized Products. In: Bender DA, Botham KM, Weil PA, Kennelly PJ,
Murray RK, Rodwell VW, eds. Harper's Illustrated Biochemistry. 29th ed. New
York: McGraw-Hill; 2011. http://0-www.accessmedicine.com.library.ccf.org
[3] GABA as a Neurotransmitter and Neurogenic
Signal - eLS - Barker - Wiley Online Library . http://0-onlinelibrary.wiley.com.library.ccf.org/doi/10.1038/npg.els.0000121/full.
Accessed 5/13/2012 2012.
[4] R Awad, D Levac, P Cybulska, Z Merali, VL
Trudeau, JT Arnason (2007) Effects of traditionally used anxiolytic botanicals
on enzymes of the gamma-aminobutyric acid (GABA) system Can J Physiol Pharmacol
85: 933-942. Doi:10.1139/Y07-083.
[5] Nicotinic Acetylcholine Receptors - eLS -
Lindstrom - Wiley Online Library . http://0-onlinelibrary.wiley.com.library.ccf.org/doi/10.1002/9780470015902.a0000245.pub2/full.
Accessed 5/20/2012 2012.
[6] Russek, S. J. 2006. γ-Aminobutyric Acid
(GABA) Receptors. eLS.
[7] Reus VI. Chapter 391. Mental Disorders. In:
Longo DL, Fauci AS, Kasper DL, Hauser SL, Jameson JL, Loscalzo J, eds.
Harrison's Principles of Internal Medicine. 18th ed. New York: McGraw-Hill;
2012. http://0-www.accessmedicine.com.library.ccf.org/content.aspx?aID=9112222.
Accessed May 27, 2012.
