L-theanine and Cancer Control
L-theanine is a potentially powerful anti-cancer drug that few people
know about. It is actually a unique amino acid from green tea that is
used as an anti-stress or sleep inducing agent. It works wonderfully.

First, some background information.

In your brain, one of the major neurotransmitters is the amino acid
glutamate. Glutamate can be considered the daytime neutransmitter,
while the neurotransmitter GABA dominates at night. Many people can't
sleep because they "can't turn off their brains", so to speak, due to
worry and stress. This means glutamate is still active as a
neurotransmitter, stimulating the awake phase of brain function.

L-theanine is a glutamate analog. This means it binds the glutamate
receptors on neurons, but it isn't a neurotransmitter. As a result,
it blocks glutamate-mediated neurotransmission and allows sleep to
take over. The process is very complicated, but this is essentially
what is going on. L-theanine puts you to sleep so don't take it
during the day if you need to stay awake.

L-theanine does something else. It blocks glutamate uptake into
cancer cells. Now this might not seem to be important but it is.
Glutamate leaks into cancer cells and is actively pumped out in
exchange for the amino acid cystine. Cystine is converted to cysteine
in the cell and forms the reducing agent glutathione. Glutathione is
a simple tri-peptide, consisting of the amino acids glycine,
cysteine, and glutamate, but it is one of the most important
molecules in the cells.

We have all heard of free radicals by now. They are dangerous if let
unchecked. Cancer cells live in a sea of free radicals and depend on
reducing agents like glutathione to keep them alive. Glutathione is
one of the molecules that neutralizes free radicals. If the levels of
glutathione, specifically reduced glutathione, become too low, cancer
cells in particular will die. All chemo drugs and radiation induce
free radicals. If the level of free radicals reach a certain level in
cancer cells, their DNA will be permanently damaged and they will
die. Cancer cells fight free radical destruction by constantly
forming reduced glutathione via a molecule called NADPH. NADPH
recycles inactive (oxidized) glutathione to the active, reduced form.
It is one of the unique aspects of cancer cell metabolism that they
can do this rapidly.

L-theanine can screw up cancer cell metabolism by blocking the uptake
of glutamate and cystine into the cell. This will reduce the
formation of new glutathione molecules and make the cancer cells much
more sensitive to death by free radicals. Normal cells are not harmed
because they have different metabolisms.

L-theanine can also enhance the chemotherapeutic efficacy of drugs
like doxorubicin by blocking the revolving door in the membrane of
cancer cells that pumps chemo drugs out as soon as they enter. This
revolving door phenomenon, consisting of multiple drug resistance
proteins, is one of the ways chemo drugs become ineffective over
time, and one of the reasons high doses of chemo drugs must be used
in the beginning of treatment BEFORE resistance takes over. If you
could block resistance, lower, less dangerous, doses of chemo drugs
could be used over a longer period of time.

One of the major pumps that reduces the efficacy of certain chemo
drugs needs gluathione to function. Read the article cited below for
more information. You can read the entire article online. In the
presence of reduced amounts of cellular glutathione, the chemo drugs
can't be pumped out the cell, thereby increasing their effectiveness.

http://www.ncbi.nlm.nih.gov/entrez/queryd.fcgi?
cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=10037191

So the take home message is that l-theanine should be used in the
treatment of all cancers. It is non-toxic, inexpensive and it works.
With or without chemo drugs, l-theanine will reduce the stability of
cancer cells by depriving them of the glutathione that they need to
survive.

So why don't oncologists recommend l-theanine to their patients? They
don't read the scientific literature in the same way we do. Most
oncologists have never heard of l-theanine.