L-Cysteine a Sulfur Containing Amino Acid Can Boost the Detox
May 08, 2009 10:00 AM
Author: Darrell Miller (firstname.lastname@example.org)
L-Cysteine is what is known as a non-essential amino acid, meaning that it can be biosynthesized by the body and hence not an essential part of your diet. Due to its possessing a thiol side chain, it is termed a hydrophilic amino acid with an affinity for aqueous systems. Because of this it is relatively highly reactive, and is therefore an important component of a large number of enzymes and proteins.
Although, after all, it is not an essential amino acid, deficiencies can occur in the young and in the old, and also in those suffering certain metabolic diseases. Dietary sources include high-protein foods such as chicken, turkey, pork, dairy products and vegetables such as cereals, broccoli, garlic and onions.
The biochemistry of this amino acid begins with another amino acid known as serine, and also methionine. The latter is fist converted to homocysteine, which is then combined with serine to form cystathionine. This is then converted into cysteine and alpha- ketobutyrate. The thiol group is highly reactive and gives cysteine its biological properties.
L-Cysteine possesses strong antioxidant properties due to the thiol group which easily undergoes redox reactions. However, it is for its detoxification effect on the body that the amino acid is mainly taken as a supplement. It is, therefore, these properties that we shall discuss first.
Cysteine can reduce the toxic effects of alcohol, such as a hangover or the more serious liver damage. The by-product of alcohol metabolism that does most damage and is responsible for the majority of the negative after-effects of excessive alcohol consumption is acetaldehyde. L-Cysteine converts acetaldehyde into the more acceptable acetic acid, and so prevents the aldehyde from having too much of a negative effect on your health and well-being. However, the results obtained from such studies have been from animals only, and the therapeutic effects of cysteine have not yet been tested on humans.
What has been tested and is known is that L-cysteine is effective in the detoxification of heavy metals in the body. A common source of heavy metal toxicity is mercury from amalgam fillings in the teeth. Although the Environmental Protection Agency (EPA) declared in 1989 that dental amalgams are a hazardous substance under the Superfund law, many people still have them in their mouths.
The thiol group and L-cysteine has a high affinity for mercury and other heavy metals, as previously stated, and a supplement can be used to remove from the body any mercury leached from mercury-based tooth fillings. It can also be used to bind to copper, lead and cadmium. Lead and cadmium are particularly toxic to the human body, and even though lead is no longer used in plumbing or paints, and cadmium in toys or paints, there are still many sources of these two heavy metals available that can lead to human toxification.
An L-cysteine supplement can be used to remove these heavy metals from the body. Any proteins containing cysteine will tightly bind heavy metals such as lead, cadmium, molybdenum, cobalt and mercury, and allow them to be excreted by the body in the usual fashion. This direct involvement in heavy metal detoxification is a very useful property of this amino acid.
Another detoxification application of L-cysteine is in direct involvement in protecting cellular glutathione levels, and also the prevention of the death of liver cells by acetaminophen poisoning. The latter is of particular interest to many people since acetaminophen is better known as paracetamol, and since this is a freely available over-the-counter drug, overdoses are not unknown. The result of an overdose is the necrosis of liver cells, with eventual liver failure and death.
The treatment of choice is N-acetylcysteine. If used within 10 hours of the overdose it is extremely effective, and even from 16 to 24 hours it is better than other controls. It is believed that the acetylcysteine liberates cysteine which, when available to the liver, enables the biosynthesis of glutathione. Glutathione can then maintain the production of the fifth metabolite required for the specific detoxification of the paracetamol/acetaminophen.
L-Cysteine is also an essential component in the biosynthesis of coenzyme A, an enzyme essential for the production of energy from fats and carbohydrates. It is also a very important component of hair, from which it is commercially produced. Without an adequate intake of L-cysteine the growth of healthy hair would not be possible.
There are several supplemental uses of L-cysteine including the treatment of bronchial conditions for which the amino acid can help to liquefy and clear mucus from the airways and lungs. It is also used to protect against side effects of chemotherapy treatment of cancers and for medical treatments for excessive exposure to radiation.
However, there are certain situations in which L-cysteine should be avoided when at all possible. Diabetics should not use it, and neither should those suffering from cystinuria, whereby large quantities of amino acids, including cystine, are excreted in their urine. L-cystine, incidentally, is formed by oxidation of L-cysteine.
Paradoxically the amino acid is one of the several hundred additives made to tobacco by the cigarette companies. Although, as with the majority of tobacco additives, its purpose is unknown there are two possible reasons for its inclusion. L-Cysteine is a known expectorant, so it could be added to promote the expectoration of mucus in the lungs which is promoted by smoking, and it also increases the production off the antioxidant glutathione that is depleted in smokers.
There are several other non-medical uses for the amino acid, but it is for is its detoxification properties that it is most used as a supplement. However, because it is largely derived from human hair or duck feathers, it may not be classed as kosher or halal in spite of many claims made to that effect, though the more expensive source of microbial fermentation from corn sugar can be.
The substance is recognized as safe by the FDA, and must be labeled as L-cysteine when it is present in a preparation intended for its therapeutic effects. Keep in mind however, that it should be avoided by diabetics.