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L-tyrosine
DESCRIPTION
L-tyrosine is a non-essential amino acid that can be made
from L-phenylalanine in the body.
FUNCTIONS
As well as being incorporated into body
proteins, L-tyrosine is the raw material from which a group
of neurotransmitters (brain chemicals) called catecholamines
are formed.
One of the catecholamines formed from L-tyrosine
is adrenalin. Adrenalin, together with other neurotransmitters,
helps to focus the mind and improve concentration during Stress
(1).
L-tyrosine is also the precursor for thyroid
hormone and the Skin pigment melanin (2).
SUPPLEMENTAL USES
L-tyrosine taken as a supplement has produced
excellent results in some types of Depression - specifically
tired, apathetic depression as opposed to high Anxiety states.
Put simply, L-tyrosine helps replace excitatory neurotransmitters
depleted by stress (1,3,4).
Similarly, L-tyrosine supplements are to
be recommended in cases of low motivation or poor concentration
(1).
SAFETY
Up to 6g/day of L-tyrosine appears to be
perfectly safe in human adults, but no more than 2000mg daily
is usually necessary for good effect.
INTERACTIONS AND CONTRA-INDICATIONS
L-tyrosine should be avoided by those with
high blood pressure or melanoma
MAO inhibitor anti-depressant drugs: It
should also not be taken by those on MAO inhibitor anti-depressant
drugs.
L-tyrosine should additionally not be taken
by pregnant women or schizophrenics.
REFERENCES
1. "The Healing Nutrients Within",
E R Braverman & C C Pfeiffer, Keats, 1987.
2. Santana C, et al. Changes in tyrosine hydroxylase activity
and melatonin synthesis in rat pineal glands throughout 72
hours of incubation. Neurosci Lett, 173;1-2:119-123 1994.
3. Kaneko M, Watanabe Km Kumashiro H. Plasma ratios of tryptophan
and tyrosine to other large neutral Amino Acids in manic-depressive
patients. Jpn J Psychiatry Neurol, 46;3:711-720 1992.
4.Fernstrom JD. Dietary Amino Acids and brain function. J
Am Diet Assoc, 94;1:71-77 1994.
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