L-glutathione is the reduced form of glutathione, and is a tripeptide synthesized in the animal and plant tissues from glycine, cysteine and glutamate. Commonly known as GSH, it contains thiol groups that are maintained in a reduced state, and is a very powerful antioxidant, considered to be the key antioxidant and protective substance in the body.
Glutathione can reduce any disulfide groups in the cytoplasm within the body of the cell, and ensures that the cytoplasm is a strongly reducing medium protecting against oxidation. It has a synergistic effect with other antioxidants to protect the body against free radicals and oxidizing agents that cause so much damage to the body through what is commonly referred to as 'oxidative stress'. However, there is more to it than that and it attaches itself to toxic chemicals and drugs in the liver and renders them into a state suitable for elimination from the body.
These toxic materials include poisonous pesticides, hydrogen sulfide, carbon monoxide, heavy metals such as mercury, cadmium and chromium and many other substances that we come into contact with due to present day pollution of our atmosphere and foodstuffs. Glutathione can also help protect the body from the effects of chemotherapy and evidence is suggesting possible links with the control of some cancers, diabetes, atherosclerosis and many other degenerative conditions caused by free radical attack and the effects of pollutants.
The way that GSH acts in the cells is that the redox state of the glutathione-glutathione disulfide couple is critical to the health of the intercellular and intracellular fluid. GSH in the reduced state of glutathione reacts with an oxidative agent such as hydrogen peroxide to form the oxidized form, glutathione disulfide and water. It hence mops up oxidizers such as peroxides and free radicals within the cytoplasm of the body's cells, and also in between the cells. The disulfide is then converted back to GSH by the combined action of the enzyme glutathione reductase and NADPH (the reducing agent nicotinamide adenine dinucleotide phosphate).
The cycle then repeats so that two molecules of glutathione continue to reduce damaging oxidizing agents without themselves being consumed. In so doing, the NADPH becomes oxidized. A continuous supply of NADPH is needed to allow GSH to undergo these biochemical reactions, and up to 10% of our blood glucose is used by the pentose phosphate pathway by which NADPH is synthesized.
Since this cycle consumes no glutathione, it would appear that a supplement is unnecessary. However, this is not the case since the molecule takes part in other reactions in the body, particularly in the elimination of toxic heavy metals from the body. Mercury is highly reactive with the thiol that GSH is, and so will bind to form a stable Hg-sulfydryl bond in the liver. This mercury-glutathione chelate is unable to bind to other proteins or gain access to the body cells, and is eventually harmlessly secreted. The same is true of many other heavy metals that are reactive with thiol's.
In this way the body is protected from the harmful effects of these heavy metals. However, it results in the loss of the glutathione, and the pollution of modern day living can take a heavy toll of the GSH content of our bodies. For this reason a glutathione supplement is recommended, especially for city dwellers that may be exposed to more heavy metals than those residing in rural areas.
However, the form in which this supplement is taken is very important, because the human digestive tract contains a significant amount of gamma-glutamyltranspeptidase. That is an enzyme which apparently destroys glutathione before it can be absorbed. However, it can be absorbed directly into the bloodstream by dissolving the pill between the teeth and inner cheek. It has also been suggestion that the supplement could be administered by injection.
Others have suggested that rather than administer a supplement, individuals could take other supplements that contain the materials needed to stimulate the formation of GSH. Substances such as vitamin C, selenium (important in GSH biochemistry), methionine, alpha-lipoic acid and glutamine could all help to increase the body's production of glutathione. A supplement of the constituent parts of cysteine, glycine and glutamic acid should also help. The dosage ranges recommended vary widely from 50mg to 500mg daily, and the effects of supplementation are not yet well know.
Some specific conditions that this wonder antioxidant is useful in treating include liver disease such as hepatitis, cirrhosis and so on. Patients suffering from these diseases show a massive reduction in their GSH content and prior GSH treatment appeared to offer a significant degree of protection in controlled clinical investigations. Patients suffering from chronic hepatitis C have been found to be associated with reduced GSH levels, particularly if also HIV positive.
Similar deficiencies have been noted in some lung conditions such as asthma and other pulmonary conditions. In such cases it has been demonstrated that administration of GSH supplements sufficient to restore normal levels of the substance improved the patients' conditions by a significant amount. Its effect on atherosclerosis appears to be significant since a decreased level of GSH peroxidase has been recorded in such patients in addition to an increase in lipid peroxides, indicating that oxidation of the arterial wall had been occurring.
Anti-viral therapies that rely on GSH biochemistry for their action have been found to be less effective in those with low GSH levels, and other studies have confirmed that supplementing with GSH improves the response to interferon treatment. These results indicate the activity of oxidizing agents and free radicals in liver conditions, and in fact this has been demonstrated by tests carried out in New York and Philadelphia in the 1990s.
This suggests that the liver is prone to damage by oxidative stress, and that GSH levels may be able to be used as an indication of potential liver disease. What is evident is that a strong case can be made for glutathione supplementation as protection against potential liver, pulmonary and cardiovascular diseases, especially by those exposed to specific polluting agents such as primary or secondary tobacco smoke, auto and diesel fumes and chemicals and pesticides.
L-glutathione is useful, not only for the elimination of toxins in the liver, but also in protecting this large and vital organ from the oxidative stress that modern living brings. L-Glutathione and its precursors are sold over the counter at your local or internet health food store.
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