Glutathione is the antioxidant that is prevalent in every cell in the human body. Glutathione is primarily synthesized in the liver where it is abundantly present.
80-90% of the blood that leaves the stomach and intestines passes through the liver. The blood carries important nutrients to the liver where they are metabolized into substances vital to life. In the same way, exogenous toxic substances reach the liver where they are either activated or transformed into less toxic derivatives. Glutathione plays a crucial role in the liver’s biotransformation system.
Free radicals and oxyradicals play an important role in the development and progression of many brain disorders such as brain injury, neurodegenerative disease, schizophrenia and Down syndrome. Glutathione is the brain's master antioxidant and plays an important protective role in the brain. Free radicals and oxidative damage in neurons is known to be a primary cause of degenerative diseases like Alzheimer's disease.
Amyloid plaques encroaching on the brain increase the production of free radicals, or oxidative stress. Antioxidants, such as vitamin C and E remove the damaging free radicals. Glutathione can prevent the death of brain cells induced by amyloid plaques in Alzheimer's disease.
Taking glutathione itself as a supplement does not boost cellular glutathione levels, since it breaks down in the digestive tract before it reaches the cells. However, intravenous glutathione therapy along with dietary supplements are effective in boosting intracellular levels of glutathione.
IS GLUTATHIONE DEPLETION
AN IMPORTANT PART OF THE
CHRONIC FATIGUE SYNDROME?
Richard A. Van Konynenburg, Ph.D.
AACFS Seventh International Conference
October 8-10, 2004
WHAT IS GLUTATHIONE? [Refs. 1--5]
• A tripeptide composed of the amino acids glutamic acid,
cysteine, and glycine. Its molecular weight is 307.33 Da.
• Found in all cells in the body, in the bile, in the
epithelial lining fluid of the lungs, and, at much smaller
concentrations, in the blood.
• The predominant nonprotein thiol (molecule containing an S-H
or sulfhydryl group) in cells.
• Its active form is the chemically reduced form, called "GSH."
• GSH is compartmentalized, with concentrations ranging from
0.5 to 10 millimolar in various organs and cell types.
• GSH serves as a substrate for enzymes, including the
glutathione peroxidases and the glutathione-S-transferases.
• When oxidized, two glutathione molecules join together via a
disulfide bond to form "oxidized glutathione," or "glutathione
disulfide," referred to as "GSSG."
• Inside cells, the concentration of GSSG is normally
maintained at less than 1% of total glutathione by the enzyme
glutathione reductase, which is powered by NADPH, produced by the
pentose phosphate shunt, part of carbohydrate metabolism.
WHAT ARE SOME OF THE FUNCTIONS OF GLUTATHIONE (GSH)? [Refs. 1--5]
• Maintains proper oxidation-reduction (redox) potential
inside cells. Redox affects the oxidation state of sulfur in
enzymes, and thus affects the rates of biochemical reactions in
• Scavenges peroxides and oxidizing free radicals directly and
also serves as the basis for the antioxidant network.
• Performs Phase II detoxication of heavy metals (such as
mercury), organophosphate pesticides, chlorinated hydrocarbon
solvents, estradiol, prostaglandins, leukotrienes, acetaminophen,
and other foreign and endogenous toxins.
• Stores and transports cysteine throughout the body.
• Transports amino acids into cells, especially cystine into
• Regulates the cell cycle, DNA and protein synthesis and
proteolysis, and gene _expression.
• Regulates signal transduction.
• Participates in bile production.
• Protects thyroid cells from self-generated hydrogen peroxide.
By means of several of the above functions, GSH plays very important
roles in (1) maintaining mitochondrial function and integrity, (2)
regulating cell proliferation, and (3) supporting the immune
HOW IS GLUTATHIONE (GSH) SYNTHESIZED IN THE BODY? [Refs. 1--5]
• GSH is synthesized inside cells by a two-step process. The
first step involves the ATP-powered enzyme glutamate cysteine
ligase (formerly called gamma-glutamylcysteine synthetase). This
step is normally the rate-limiting reaction, and is controlled by
the cellular redox state and feedback inhibition, among other
factors. The second step makes use of the ATP-powered enzyme
• The necessary substrates are cysteine (which is often the
rate-limiting substrate when GSH is depleted), glutamic acid (or
glutamine) and glycine. Cysteine and glutamic acid are joined
together in the first step, and glycine is added in the second step.
• The liver is the main producer and exporter of GSH.
• A few epithelial cell types can import GSH molecules
• Most cell types use the gamma glutamyl (or GSH scavenging)
cycle. This cycle makes use of the plasma-membrane-bound exoenzymes
gamma-glutamyl transpeptidase and dipeptidase. This cycle
disassembles GSH outside the cell and imports the parts for
reassembly inside. It also serves as a transport mechanism to bring
other amino acids into the cell, cystine(di-cysteine) being favored.
IS GLUTATHIONE DEPLETED IN CHRONIC FATIGUE SYNDROME?
There is considerable evidence that it is, at least in a substantial
fraction of Chronic-Fatigue-Syndrome patients. Here are the results of all the published
studies that bear on this question:
• GSH depletion in Chronic-Fatigue-Syndrome was first suggested by Droge and Holm
• Cheney [7,8] reported that his Chronic-Fatigue-Syndrome clinical patients were
almost universally low in GSH.
• Richards et al.  found that patients could be divided
statistically into two distinct groups, one having significantly
elevated erythrocyte GSH relative to a healthy control group, and
the other having significantly lower values.
• Fulle et al.  found elevated total (reduced plus
oxidized) glutathione in muscle biopsy specimens from PWCs relative
to healthy controls, but they did not report values for reduced
• Manuel y Keenoy et al.  found that a subgroup of
fatigued patients with low magnesium, whose body stores of Mg did
not improve with supplementation, had significantly lower GSH.
• Manuel y Keenoy et al.  did not find a significant
difference between CFS patients and fatigued controls in terms of
whole-blood GSH, but they did not compare with a healthy control
• Kennedy et al.  found significantly lower red blood cell
GSH in PWCs compared to healthy controls (p=0.05).
• Kurup and Kurup  found significantly lower red blood
cell GSH in myalgic encephalomyelitis patients compared to healthy
IN THE GENERAL POPULATION, WHAT FACTORS OR CONDITIONS ARE KNOWN TO
CAUSE DECREASES IN INTRACELLULAR GLUTATHIONE CONCENTRATIONS?
These factors and conditions can be divided into three groups:
• The first group is made up of those that (1) lower the rate
of GSH synthesis or the rate of reduction of GSSG to GSH, or (2)
raise the rate of export of GSH from cells, or (3) lead to loss of
GSH from the scavenging pathway. This group includes the
following: genetic defects , elevated adrenaline secretion [16-
20] due to various types of stress, deficient diet  or fasting
, surgical trauma [21,22], burns , and morphine .
• The second group is comprised of toxins that conjugate GSH
and remove it from the body , such as organophosphate
pesticides, halogenated solvents, tung oil (used on furniture),
acetaminophen and some types of inhalation anesthesia.
• The third group is comprised of conditions that raise the
production rates of reactive oxygen species high enough to produce
oxidative stress, causing cells to export GSSG. These include
strenuous or extended exercise , infections (producing leukocyte
activation) , toxins that produce oxidizing free radicals during
Phase I detoxication by cytochrome P450 enzymes , ionizing
radiation , iron overload , and ischemia--reperfusion events
(such as stroke, cardiac arrest, subarachnoid hemorrhage, and head
STRESS, DISTRESS, AND STRESSORS
• For purposes of this presentation, stressors are defined in
the broad sense as events, circumstances or conditions that place
demands on a person and tend to move his or her body out of
allostatic balance. Allostasis is similar to homeostasis, but
allows for changes in the set-point over time to match life
circumstances . Stressors can be classified as physical,
chemical, biological, or psychological/emotional.
• Stress is the state that results from the presentation of
such demands. Selye  defined stress as "the state manifested by
a specific syndrome which consists of all the nonspecifically-
induced changes within a biologic system." Although Selye
emphasized the nonspecifically-induced responses, the body also
exhibits specific responses that depend on the type of stress .
• Stress can be of a beneficial or a destructive nature.
Distress is the destructive type of stress .
• The perceived stress that people experience depends not only
on the stressors to which they are subjected, but also on "their
appraisals of the situation and cognitive and emotional responses to
• A person's history of both the occurrence of stressors and
of the degree of perceived stress can be evaluated by structured
interviews, and this has been done in a number of studies of CFS
IS THERE EVIDENCE FOR HIGHER OCCURRENCE OF STRESSORS IN CFS PATIENTS
PRIOR TO ONSET THAN IN HEALTHY NORMAL CONTROLS?
YES. The types of stressors found to have higher occurrence in one
or more CFS risk factor studies [34-45] include the following:
• Physical: Aerobic exercise (especially of long duration),
physical trauma (especially motor vehicle accidents) and surgery
• Chemical: Exposure to toxins such as organophosphate
pesticides, solvents and ciguatoxin.
• Biological: Infections, immunizations, blood transfusions,
insect bites, allergic reactions, and eating or sleeping less.
Stressful life events, including death of a spouse, close family
member or close friend; recent marriage; troubled or failing
marriage, separation, or divorce; serious illness in immediate
family; job loss, starting new job, or increased responsibility at
work; and residential move.
Difficulties, including ongoing problems with relationships,
persistent work problems or financial problems, mental or physical
violence, overwork, extreme sustained activity, or "busyness."
Dilemmas "A dilemma is a situation in which a person is challenged
to choose between two equally undesirable alternatives."
Choosing inaction in response to a dilemma leads to further negative
Problems in childhood, including significant Depression or anxiety,
alcohol or other drug abuse, and/or physical violence in parents or
other close family members; physical, sexual or verbal abuse, low
self-esteem and chronic tension or fighting in the family.
IS THERE EVIDENCE FOR HIGHER PERCEIVED STRESS IN CFS PATIENTS PRIOR
TO ONSET, COMPARED TO HEALTHY CONTROLS?
YES. Three studies [34, 37, 38] found that CFS patients rated their
level of perceived stress prior to onset higher than did healthy,
normal controls for a similar period of time.
IN VIEW OF THE STRONG CORRESPONDENCE BETWEEN THE RESULTS OF THE CFS
RISK FACTOR STUDIES AND THE KNOWN GSH DEPLETORS, IT IS NOT
SURPRISING THAT GLUTATHIONE BECAME DEPLETED IN MANY CFS PATIENTS.
It appears that the CFS patients who were studied had undergone a
variety of factors and conditions that are known to deplete
HOW DOES THE NEUROENDOCRINE SYSTEM RESPOND TO STRESS?
• This system manifests both specifically- and nonspecifically-
induced responses to stress . The nonspecifically-induced
responses address the combined load of all the various types of
stress that are being experienced simultaneously.
• The nonspecific responses are mediated by three parts of
this sytem: (1) the hypothalamus-pituitary-adrenal (HPA) axis, which
produces cortisol and other glucocorticoids, (2) the sympathetic-
adrenomedullary system, which produces epinephrine (adrenaline), and
(3) the sympathoneural system, which produces norepinephrine
• Rapid-onset CFS patients report that they had a normal
response to stress prior to their onset of CFS. Therefore, it can
be surmised that if they experienced a high load of combined long-
term stress lasting a few months to several years prior to their
onset, they were subject to high levels of both cortisol and
adrenaline during this extended period of time.
• Note that depleted rather than elevated cortisol levels are
frequently observed clinically in CFS patients (Cleare ).
However, the decrease in cortisol secretion occurs later in the
pathogenesis: "…the bulk of the data assembled to date is
compatible with the view that the disruption in adrenocortical
function is a late finding, and that elucidating the status of the
central nervous system components which drive the regulation of the
HPA axis would be crucial to a more complete understanding of this
final event." (Demitrack )
WHAT ARE THE EFFECTS OF LONG-TERM ELEVATED LEVELS OF CORTISOL AND
ADRENALINE ON THE IMMUNE SYSTEM AND ON GLUTATHIONE LEVELS?
• Elevation of cortisol is known to suppress the inflammatory
response by several mechanisms, including decreasing the _expression
of cytokines and cell adhesion molecules, and decreasing the
production of prostaglandins and leukotrienes . This effect is
beneficially used therapeutically in many cases, but it can also
have a down side if an infection is present.
• Long-term elevation of cortisol is also known to suppress
cell-mediated immunity and to cause a shift to the Th2 type of
immune response. Several mechanisms are involved, including
suppressing the secretion of IL-1 by macrophages, inhibiting the
differentiation of monocytes to macrophages, inhibiting the
proliferation of T lymphocytes, and increasing the production of
endonucleases, which increases the rate of apoptosis of lymphocytes
• Long-term elevation of adrenaline can be expected to deplete
GSH, because adrenaline decreases the rate of synthesis of
glutathione by the liver (Estrela et al. ), increases its rate
of export from the liver (Sies and Graf ; Haussinger et al.
; Estrela et al. ), and decreases the rate of reduction
(recycling) of oxidized glutathione (Toleikis and Godin ).
HOW DO VIRAL INFECTIONS ARISE AT THE ONSET OF CHRONIC FATIGUE
I propose that glutathione depletion is the trigger for reactivation
of endogenous latent viruses in CFS (hypothesis).
Here's the support for this hypothesis:
• Most of the evidence points to reactivation of latent
endogenous viruses at the onset of CFS, rather than new, primary
infections (Komaroff and Buchwald )
• Infections by members of the Herpes family of viruses, such
as Epstein-Barr virus and HHV-6 are commonly found in CFS patients
• GSH depletion is associated with the activation of several
types of viruses [50-53], including Herpes simplex type 1 (HSV-1)
. Raising the GSH concentration inhibits replication of HSV-1
by blocking the formation of disulfide bonds in glycoprotein B, a
protein that is necessary for proliferation of the virus .
• Glycoprotein B is also found in all other Herpes family
viruses studied, including EBV and CMV , and very likely is
present also in HHV-6 and performs the same vital function there
It thus appears very likely that GSH depletion is the trigger for
the reactivation of the latent forms of all the Herpes family
viruses (hypothesis). Since glutathione likely becomes depleted
prior to the onset of CFS, and since infections by these viruses are
commonly found in CFS, it seems likely that glutathione depletion is
responsible for initiating the viral infections at the onset of CFS
CAN ELEVATED CORTISOL AND DEPLETED GLUTATHIONE EXPLAIN THE IMMUNE
• The shift to the Th2 immune response, as observed in CFS
, is a known effect of both elevated cortisol  and of
depleted GSH [58, 59]. I suggest that elevated cortisol produces
the Th2 shift initially, and that it is maintained later in the
pathogenesis by GSH, after the cortisol level drops, due to blunting
of the HPA axis.
• The following dysfunctions seen in CFS  are known
effects of depleted GSH: lowered natural killer cell and cytotoxic
T cell cytotoxicity; and inability of T cells to proliferate, as
seen in decreased mitogen-induced proliferative response of
lymphocytes and decrease in delayed-type hypersensitivity .
In addition, I hypothesize the following:
• The observed chronic immune activation and the observed
continuous activation of the RNase-L pathway in CFS result from the
failure of cell-mediated immunity to defeat detected infections,
owing to the above effects.
• The observed low molecular weight RNase-L results from lack
of inhibition of caspases because of thiol (GSH) depletion, and they
cleave the RNase-L. (Caspases are normally inhibited by thiols.)
• The observed elevated numbers of immune complexes result
from the failure of cell-mediated immunity and the shift to the Th2
response, which produces elevated levels of antibodies.
• The observed elevation in antinuclear antibodies results
from the observed higher rate of apoptosis, which is a known
consequence of GSH depletion.
HOW DOES PHYSICAL FATIGUE ARISE AT THE ONSET OF CFS?
• When the immune system detects the viral infection, it
• In attempting to proliferate, the lymphocytes draw upon the
already depleted supplies of GSH and its precursor, cysteine (or
• Being in the blood, the lymphocytes have earlier access to
GSH and cysteine than do the skeletal muscles.
• Competition in CFS between the immune system and the
skeletal muscles for these substances has already been hypothesized
by Bounous and Molson , and I agree with their hypothesis.
• The skeletal muscles become more depleted in GSH.
• This produces a rise in their concentration of
peroxynitrite. (Peroxynitrite forms from superoxide and nitric
oxide. Superoxide becomes elevated because the depletion of GSH
causes a rise in hydrogen peroxide, and this exerts product
inhibition on the superoxide dismutase reaction, causing superoxide
levels to rise.)
• As Pall  has stated, "Peroxynitrite reacts with and
inactivates several of the enzymes in mitochondria so that
mitochondrial and energy metabolism dysfunction is one of the most
important consequences of elevated peroxynitrite."
• The resulting partial blockades in the Krebs cycles and the
respiratory chains in the red, slow-twitch skeletal muscle cells
decrease their rate of production of ATP. Since ATP is what powers
muscle contractions, the lack of it produces physical fatigue. It
becomes chronic because GSH remains depleted.
SINCE GLUTATHIONE IS AT THE BASIS OF THE BODY'S ANTIOXIDANT SYSTEM,
ITS DEPLETION CAN BE EXPECTED TO PRODUCE OXIDATIVE STRESS. HAS THIS BEEN OBSERVED IN CFS?
YES. Oxidative stress is now well-established in CFS.
The following researchers have presented evidence for oxidative
stress in CFS:
• Ali (1990 and 1993)
• Cheney (2000a & b)
• Richards et al. (2000a & b)
• Fulle et al. (2000)
• Manuel y Keenoy et al. (2001)
• Vecchiet et al. (2003)
• Kennedy et al. (2003)
• Smirnova and Pall (2003)
SINCE GLUTATHIONE NORMALLY REMOVES MERCURY FROM THE BODY, ITS
DEPLETION CAN BE EXPECTED TO ALLOW BUILDUP OF MERCURY IN CFS
PATIENTS. IS THIS OBSERVED?
YES. While there are no published controlled studies of mercury
level testing in CFS patients, several clinicians who specialize in
treating CFS have reported that many of their patients have high
In addition, immune testing has shown significantly elevated
hypersensitivity to mercury in many CFS patients (Stejskal et al.,
1999; Sterzl et al., 1999; and Marcusson, 1999). This suggests that
the immune system has responded to elevated mercury levels.
(Note that there have been epidemiological studies that showed no
evidence that dental Amalgams are associated with CFS as a causal
factor. However, this does not constitute evidence that Amalgams do
not give rise to elevated mercury levels after CFS onset in people
who have Amalgams and who may have developed CFS as a result of
CAN GLUTATHIONE DEPLETION EXPLAIN AUTOIMMUNE THYROIDITIS IN CHRONIC
• It is known that thyroid cells normally produce hydrogen
peroxide to oxidize Iodide ions as part of the pathway for producing
thyroid hormones. Normally, this oxidation occurs outside the cell
membrane, and the interior of the cell is protected from the
hydrogen peroxide by intracellular GSH (Ekholm and Bjorkman, 1997).
• It has been shown by Duthoit et al., (2001) that if hydrogen
peroxide is allowed to enter thyroid cells, it will attack and
cleave thyroglobulin, producing C-terminal fragments that can
diffuse into other cells and are recognized by autoantibodies from
patients with autoimmune thyroid disease. This suggests that
hydrogen peroxide entry into thyroid cells may be the cause of this
• It has been shown by Wikland et al. (2001), using fine
needle aspiration cytology, that about 40% of patients suffering
from chronic fatigue show evidence of chronic autoimmune
thyroiditis, even though TSH levels were in the normal range in many
• HYPOTHESIS: It seems likely that GSH depletion accounts for
this high prevalence.
WHY IS CFS MORE PREVALENT IN WOMEN THAN IN MEN?
• It has been found recently that the monthly menstrual cycle
in women presents an additional demand on GSH that does not occur in
men. 17-beta estradiol is elevated in women from the late
follicular phase through the early luteal phase of the cycle. This
hormone stimulates the activity of the enzyme glutathione peroxidase
(Serviddio et al., 2002).
• Perhaps this occurs to protect against elevated production
of reactive oxygen species generated during the rapid growth of the
• The resulting reactions depress the endometrial GSH level
during the time the estradiol level is high (Serviddio et al., 2002).
HYPOTHESIS: I propose that this additional demand for GSH in women
exacerbates the GSH depletion that occurs as a result of other
causes, and that this makes women more vulnerable to developing CFS,
accounting for the higher observed prevalence of CFS in women than
WHAT APPROACHES HAVE BEEN USED TO BUILD GLUTATHIONE?
• Diet high in sulfur-containing amino acids (as in animal-
based protein, such as milk, eggs and meat) and antioxidants (as in
fresh fruits and vegetables).
• Diet high in GSH, e.g. fresh fruits and vegetables and meats
(Jones et al., 1992).
• N-acetylcysteine together with glutamic acid or glutamine
and glycine (Clark, http://www.cfsn.com),
or NAC together with dietary
protein (Quig, 1998).
• Non-denatured whey protein (Bounous et al., 1989)
• Oral reduced glutathione (Jones et al., 1989)
• Intravenous reduced glutathione (Foster et al., 2003)
• Intramuscular reduced glutathione (Salvato, 1998)
• Transdermal reduced glutathione skin cream
• Sublingual reduced glutathione troches (Schaller,
Hunjan and Evered, 1985)
• Reduced glutathione rectal suppositories (one supplier is
Hopewell Pharmacy, New Jersey)
• Reduced glutathione aerosol (Buhl et al., 1990)
• Reduced glutathione nasal spray (Testa et al., 1995)
HAS GLUTATHIONE REPLETION BEEN USED CLINICALLY IN CFS, AND IF SO,
WHAT HAVE BEEN THE RESULTS?
Patricia Salvato, M.D. has used intramuscular injections of GSH
combined with ATP clinically for several years. In 1998 she
reported on a study of 276 CFS patients, using 100 mg of GSH and 1
mg of ATP weekly. After 6 months of treatment, 82% experienced
improvement in fatigue, 71% experienced improvement in memory and
concentration, and 62% experienced improvement in levels of pain.
Paul Cheney, M.D. reported in 1999 on his clinical use of oral
undenatured whey protein in CFS patients. The dosage varied with
different patients, up to 40 grams per day. He reported that
several of his patients improved on this treatment, and some who had
had active infections with herpes family viruses, mycoplasma, or
chlamydia were cleared of them by this treatment.
John S. Foster, M.D. and his colleagues reported in 2002 on their
use of GSH in an intravenous fast push (over 2 to 3 minutes).
Dosage ranged up to 2,500 mg, 1 or 2 times weekly, as part of a
detoxification protocol used on a variety of patients, including
some with CFS. They reported that the treatment has been promising
in addressing neurodegenerative and neurotoxic disorders.
IS REPLETION OF GLUTATHIONE LIKELY TO BE THE COMPLETE ANSWER FOR
GSH depletion occurs near the beginning of the complex pathogenesis
of CFS. There are likely to be many interactions and vicious
circles as the pathogenesis develops into the pathophysiology, and
there may also be damage that is difficult to correct. The
mediators of such damage would likely be infections, toxins and
reactive oxygen species, all of which are able to build up because
of the depletion of GSH. It is likely that a multifaceted treatment
protocol will be necessary.
When GSH repletion is begun in patients who have been GSH-depleted
for extended periods of time, their immune and detoxication systems
can begin to function at higher levels of performance. If their
bodies have accumulated elevated levels of toxins (especially
mercury) and infections, glutathione repletion can cause significant
Herxheimer-type reactions as pathogens are killed and toxins are
mobilized. Care should be taken to proceed slowly and cautiously in
such cases in order to avoid moving toxins into the central nervous
system or exacerbating symptoms to a level that is intolerable to
Glutathione depletion is an important aspect of the pathogenesis of
chronic fatigue syndrome for at least a substantial fraction of