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L-cysteine
DESCRIPTION
L-cysteine is a non-essential amino acid and can be made in
the body from L-methionine and L-serine. The main feature
of L-cysteine is that it is a Sulphur -containing amino acid.
L-cysteine contributes to protein structure through the cross-linking
that occurs between the Sulphur components.
FUNCTIONS
In combination with other
nutrients, L-cysteine is a potent antioxidant, protecting
cells against the effects of radiation, Smoking and other
toxins such as alcohol and heavy metals.
L-cysteine is a major part of the peptide gluthathione, which
in turn is a component of the antioxidant enzyme, gluthathione
peroxidase.
L-cysteine is also necessary
for the production of coenzyme A - a vital enzyme in energy
production from food. It is additionally a component in the
blood sugar-regulating compound, glucose tolerance factor.
Furthermore, L-cysteine
is an important structural component of hair. The growth and
health of hair depends on an adequate L-cysteine intake.
SUPPLEMENTAL USES
L-cysteine may be used for:
Bronchial conditions (L-cysteine
helps to liquefy and clear mucus from the lungs and bronchial
tubes (1).
Radiation protection - especially in the context of medical
treatments (1).
Protection against side effects of chemotherapy treatment
(1).
High cobalt and Molybdenum levels (L-cysteine and/or L-methionine)
have been shown to alleviate the symptoms of excessive levels
of these metals and may also be useful in other cases of heavy
metal toxicity (1).
Hair loss and poor hair growth (1).
SAFETY
Although 3-4g daily can
be taken without side effects, it is not normally necessary
to take more than 1g daily. Over 7g of L-cysteine can lead
to the formation of L-cystine Kidney stones. High doses of
L-cysteine should ideally be taken with a Vitamin C supplement
as this may help to prevent the oxidation of L-cysteine to
L-cystine.
INTERACTIONS AND CONTRA-INDICATION
Diabetes and Cystinuria
L-cysteine should be avoided by diabetics. People with the
hereditary disorder cystinuria (in which large amounts of
L-cystine and other Amino Acids are excreted in the urine),
should also avoid L-cysteine supplements.
N.B. L-cysteine should not
be confused with L-cystine, which has completely different
properties and can be harmful if allowed to build up in the
body. L-cystine is the oxidised form of L-cysteine.
REFERENCES
1. "The Healing Nutrients
Within", E R Braverman & C C Pfeiffer, Keats, 1987.
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