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| Article: NEUROTRANSMITTERS,AMINO ACIDS & MENTAL HEALTH-III : THE ROLE OF L-TYROSINE - by David Puchol Esparza Psychologist and Naturopath | ||
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Catecholamines
and Mental Health Catecholamines
are biologically active compounds that critically influence many specific
behaviors,cognitive functions, and emotional experiences.Dopamine,
Noradrenaline, and Adrenaline are all known as Catecholamines.Noradrenaline
and Adrenaline are also popularly referred to as Norepinephrine and
Epinephrine. Adrenaline is a neurotransmitter responsible for the well-known
"fight or flight" response which prepares the body to cope with
stress,challenges,and potential
dangers or threats.Dopamine and Norepinephrine act as potent,immediate, and
effective ‘stimulants’ in our brain,although this is not their only role
in our mental health state... A.-Dopamine
is a chemical messenger involved in some key aspects... 1.-Too
much Dopamine has been consistently associated with Schizophrenia, and too
little is linked with some forms of depression as well as the muscular
rigidity and tremors usually observed in Parkinson’s Disease. 2.-Schizophrenia
is treated with psychoactive drugs (neuroleptics) which ‘block’ the
binding of Dopamine to its postsynaptic receptor sites.The dopamine
hypothesis of Schizophrenia is that there is excessive Dopamine stimulation
in the frontal lobe due to a combination of genes,excessive levels of stress
or some as yet unknown aspect of the environment such as toxins or a
perinatal virus. 3.-Parkinson's
Disease is accompanied by a systematic destruction of Dopamine neurons in
the substantia nigra of the midbrain which send their axon terminals to the
striatum which is involved in motor control. Parkinson's Disease is usually
treated with L-Dopa which is a precursor for the production of Dopamine.
B.-Epinephrine
and Norepinephrine are neurotransmitters involved in many behaviors... 1.-Norepinephrine
plays a role in attention and general arousal level. Waking behavior is
enhanced by psychoactive drugs which ‘activate’ Norepinephrine systems
while REM sleep occurs when Norepinephrine systems are at their lowest level
of activity. 2.-Norepinephrine
is depleted in situations of chronic or prolonged stress and this depletion
may contribute to the harmful effects of stress.Aerobic exercise appears to
enhance and optimize the brain's ability to deal more effectively with
stress and protect it from depletion of this essential neurotransmitter. 3.-Norepinephrine
is also involved in Mood Disorders.Some of the synthetic drugs which are
used to treat Major Depression block the reuptake of Norepinephrine at the
synapse.Too little Norepinephrine has been associated with Depression, while
an excess has been associated,according to recent scientific research,with
Schizophrenia and Psychotic Disorders. Catecholamines,L-Phenilalanine
and L-Tyrosine
Phenylalanine
occurs in two chemical forms: L-Phenylalanine
(a natural amino acid found in proteins) and its mirror
image,D-Phenylalanine,a form
synthesized in a laboratory.Adults use about 90% of the Phenylalanine
consumed to make Tyrosine, children about 40%. Tyrosine in turn is converted
into L-Dopa, Norepinephrine, and Epinephrine,three key
neurotransmitters.Folic Acid, Niacin, Vitamin C, and Copper are needed to
support Tyrosine metabolism into these key substances.Because Tyrosine is a
precursor of the neurotransmitters Norepinephrine and Dopamine, both of
which regulate mood,cognition and behavior, this amino acid has been
proposed as a natural and safe treatment for various conditions in which
mental function is impaired or slowed down, such as Chronic Fatigue or
Depression. Tyrosine
is known as the ‘antidepressant’ amino acid because appears to have a
mild stimulatory effect on the Central Nervous System. It has a mild
antioxidant effect, binding up free radicals that can cause damage to the
cells and tissues, and is useful in smokers, or those exposed to chemicals
and radiation. Tyrosine seems to relieve the physical symptoms of stress if
administered before the stressful
situation occurs.L-Tyrosine has also been used,
usually in a dose of 1–2 grams a day, for low sex drive, Parkinson's
disease, and in programs for substance abuse disorders or weight loss.L-Tyrosine
supplementation can help reduce the irritability, depression, and fatigue
associated with Premenstrual Syndrome.Tyrosine,according to some experts,may
also stimulate growth hormone and can act as a mild appetite suppressant. Although
Tyrosine is found in fish,soy products,chicken, almonds, avocados, bananas,
dairy products, lima beans,and sesame seeds, it is difficult to get
‘therapeutic amounts’ of Tyrosine exclusively
from food.Tyrosine
supplements should be taken 30 minutes before meals three times per day on
an empty stomach.Tyrosine should be avoided with other amino acids or with
proteins such as milk or eggs. Tyrosine is considered more effective if it
is taken with up to 25 mg of vitamin B6. As
an antidepressant, 500–1000 mg. of L-Tyrosine can be taken two or three
times during the day. Since Tyrosine has a more stimulating antidepressant
effect, taking 1000 to 1500 mg. of L-Tryptophan
at night for sleep may be a good therapeutic combination to help in
mild to moderate depression (Haas,1992). Acetyl
L-Tyrosine (ALT) is a more rapidly absorbed and bioavailable form of the
amino acid L-Tyrosine.Its impact on clinical depression is a significant
contribution to nutritional medicine. The most pronounced effect is on
depressive states characterized by apathy and lethargy.For the agitated,
verwrought type of depression, L-Tryptophan and 5-HTP, seem to work even
better. Tyrosine seems to be generally safe, though at high dosages some people have reported some side effects like nausea,diarrhea,headache,vomiting, or excessive nervousness. Tyrosine should not be taken by patients who are taking MAOI’s for Depression or by patients with high blood pressure because it can cause dangerous elevations of blood pressure.Levodopa may interfere with the absorption of Tyrosine and could reduce Tyrosine levels in the blood.Tyrosine may also cause the growth of malignant melanoma by promoting the division of cancer cells. Maximum safe dosages for young children, women who are pregnant or nursing, or those with severe liver or kidney disease have not been established. Clinical Applications of
L-Tyrosine : Scientific Evidences
1.-One
clinical study detailed two patients with long-standing depression who
failed to respond to MAOI’s and
Tricyclic Drugs as well as electroconvulsive therapy.One patient required 20
mg/day of dextroamphetamine to remain depression-free, and the other
required 15 mg/day of D,L-amphetamine. Within two weeks of starting
L-Tyrosine, 100 mg/kg once a day before breakfast, the first patient was
able to eliminate all dextroamphetamine, and the second was able to reduce
the intake of D,L-amphetamine to 5 mg/day. In another case report, a
30-year-old female with a two-year history of depression showed marked
improvement after two weeks of treatment with L-Tyrosine, 100 mg/kg/day in
three divided doses.No adverse
side effects were
seen during
the study period
(Goldberg,1980). 2.-A
double-blind study followed 27 individuals,half of whom received DL-phenylalanine
(150 to 200 mg daily) and the other half imipramine (100 to 150 mg). When
they were reevaluated after 30 days, both groups had improved by a
statistically equal amount (Sabelli
et al.,1986). 3.-Phenylalanine
has been used for treatment of depression in the D-, L-, or DL- forms,
probably because it forms tyrosine, an excitatory
neurotransmitter.L-Phenylalanine works best in bipolar disorders (with manic
and depressive states) in doses of 500 mg. twice daily up to 2–3 grams
daily, along with 100 mg. of vitamin B6 twice daily, whereas D- and DL-Phenylalanine
work better for affective depression (Haas,1992). 4.-According
to preliminary evidence, Tyrosine supplements may help fight fatigue and
improve mental function in people who are deprived of sleep or exposed to
other forms of stress.A double-blind,placebo-controlled study that enrolled
20 U.S. Marines suggests that tyrosine can improve mental alertness during
periods of sleep deprivation. In this study, the participants were deprived
of sleep for a night and then tested frequently for their alertness
throughout the day as they worked. Compared to placebo, 10 to 15 g of
Tyrosine given twice daily seemed to provide a "pick-up" for about
2 hours (Neri et al.,1995). 5.-Some
experts suggest that
L-Tyrosine aids in the functions of the adrenal, thyroid and pituitary
glands. This specific amino acid is easily converted into thyroid hormone,
or thyroxin,"which plays an
important role in controlling metabolic rate, skin health, mental health,
and growth rate. Tyrosine is specifically used to treat depression because
it is a precursor for those neurotransmitters that are responsible for
transmitting nerve impulses and essential for preventing depression."
(Segala,2000). Conclusion The
optimum amino acid balance in the body/mind is an essential and often
critical component of our mental health state. Neurotransmitters are
‘manufactured’ in the brain from the amino acids we extract from foods,
and their supply is entirely dependent on the presence of these precursor
amino acids.Without adequate amino-acid conversion, neurotransmitters are no
longer produced in sufficient amounts.These defficiencies and nutritional
imbalances,according to many nutritional experts and mental health
professionals,may provoke ‘emotional’ symptoms, including depression and
/ or anxiety.According to the Encyclopedia of Natural Medicine, "A
deficiency of any single nutrient can alter brain function and lead to
depression, anxiety, and other mental disorders".Supplementing this
specific amino acid in people displaying evidence of neurotransmitter
deficiency has been shown to reduce effectively depressive and anxiety
symptoms in many people. Psychoactive
drugs and psychotherapy strategies
are not always the best or the only option for an effective and safe
treatment of mental disorders.The nutritional treatment of disorders like
Depression, Anxiety or Insomnia includes strategic dietary modifications
(e.g. the role of hypoglycemia or essential fatty acids intake), supportive
treatment with micronutrients (e.g.vitamins and minerals), and
supplementation with specific amino acids (e.g.Tirosine) in a systematic
protocol that aims to correct the biochemical imbalances and nutritional
defficiencies in the brain understood to be a key contributing factor in
many psychiatric and emotional disorders. References
Bratman,S.
; Kroll,D. & DePalma,A.(2000)The Natural Pharmacist : Natural Health
Bible.California : Prima Health. Gelenberg,A.
; Wojcik,J. y Falk,W.(1990). Tyrosine for depression :a double-blind trial.
J Affect Disord , 19 , 125-132. Goldberg,I.(1980).L-Tyrosine
in Depression.Lancet , 2 , 364. Haas,E.(1992).Staying
Healthy With Nutrition.The Complete Guide to Diet and Nutritional
Medicine.Celestial Arts. Meyers,S.(2000).Use
of Neurotransmitter Precursors for Treatment of Depression. Altern Med Rev ,
5 (1) , 64-71. Neri,D.;Wiegmann,D.;Stanny,R.
et al. (1995).The effects of tyrosine on cognitive performance during
extended wakefulness. Avit Space Environ Med.
, 66 , 313–319. Sabelli,H.;Fawcett,J.;Gusovsky,F.
et al.(1986).Clinical studies on the phenylethylamine hypothesis of
affective disorder:urine and blood phenylacetic acid and phenylalanine
dietary supplements. Journal of Clinical Psychiatry , 47 , 66–70. Segala,M.(2000).Disease
Prevention and Treatment.Life Extension Foundation. Young,S.(1996).Behavioral effects of dietary neurotransmitter precursors : Basic and clinical aspects. Neurosci Biobehav Rev , 20 , 313-323. |
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Licensed Psychologist. Diploma in Naturopathy. Master Practitioner of NLP. Postgraduate Qualifications in Clinical Psychology,Hypnosis, and Nutrition. Contact : dpuchol@yahoo.es |
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