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The hormone melatonin is an efficient free radical scavenger and
singlet oxygen quencher. Singlet oxygen is an "excited"
oxygen molecule whose excessive discharge of energy causes damage
to other body molecules. While most antioxidants work only in certain
parts of certain cells, melatonin can permeate any cell in any part
of the boy. Most importantly, melatonin is one of the few antioxidants
that can penetrate the mitochondria which produce energy. Melatonin
does seem to protect the mitochondria from free radical damage.
Melatonin is an important hormone that is secreted by the pineal
gland in the brain. Since its identification in 1958, studies have
shown that melatonin plays a crucial role in ordering the complex
hormone secretion patterns that regulate the body's circadian rhythm.
Melatonin also helps control sleeping and waking periods, because
its release is stimulated by darkness and suppressed by light. It
also controls the timing and release of female reproductive hormones,
affecting menstrual cycles, menarche, and menopause.
Overall levels of melatonin in the body also contribute to the
process of aging. The standard rhythmic pattern of melatonin levels
are absent until about 3 months of age. After that, the nocturnal
levels of melatonin are at their highest for the first few years
and then begin to decline as puberty begins. After puberty, nocturnal
melatonin levels are relatively stable throughout adulthood and
then fall as people age. In old age, the nocturnal rise in melatonin
may be barely detectable. Because melatonin opposes the degeneration
caused by high levels of corticosteroids (e.g., protein catabolism,
suppressed immune function, and altered blood glucose metabolism),
higher melatonin levels may help promote health and extend life
span.
Studies show that jet lag is most likely caused by a disrupted
circadian rhythm that can be effectively adjusted by using melatonin.
A dosage of 1 and 3 mg every evening for a week acclimates you quickly
to a new sleep schedule, restoring slumber (in the dark) with a
minimum amount of fatigue upon awakening (when it's light).
Taking timed-released formulas, in dosages as low as a single milligram,
may be more advantageous. They prevent the hormone's level from
peaking too soon, which will awaken you too early.
Insomnia that is seen in the elderly and in some children with
sleeping disorders is usually caused by low melatonin levels. That,
too, can be treated with the proper supplementation. Taking 0.3
mg of melatonin at bedtime, one study demonstrated, markedly improves
sleep patterns among elderly people who had problems falling asleep
and remaining asleep for the remainder of the night.
Childhood diseases that may cause melatonin-related sleep disorders
include autism, epilepsy, Down's syndrome, and cerebral palsy. Melatonin
supplementation can also benefit blind people whose sleeping rhythms
are disturbed. Melatonin is not effective as a sleeping aid for
persons with normal melatonin levels.
The hormone rejuvenates several components of our natural defense
system, and their strength combines to create a more powerful immunity.
One way in which melatonin might fight cancer is by stimulating
the immune system's natural killer cells. Other studies confirm
that the hormone sends white blood cells a signal to protect the
body, and animal research points to its ability to bolster overall
immunity. Some scientists speculate that this immune impact might
be targeted against AIDS.
Some metastataic cancer patients have lived longer by taking at
least 12 to 20 mg of melatonin every night. Even daily dosages of
200 mg, according to European investigators, are safe.
As the body's concentration of melatonin falls, reasearch affirms,
the liklihod of heart disease rises. A deficiency is also associated
with elevated blood levels of cholesterol and triglycerides.
One pilot study suggests that melatonin (10 g) could prevent cluster
headaches from taking place.
A melatonin deficiency commonly appears in people with Alzheimer's
disease. Alzheimer's affected brain cells are also damaged by hydroxyl
, one of the free radical molecules that melatonin controls so effectively.
Many studies have shown that some patients suffering from depression
have lower-than-normal melatonin levels. Seasonal affective disorder
(SAD) is often effectively treated with phototherapy, and research
has shown that SAD patients often have delayed melatonin rhythms
in the winter.
While some forms of depression may have direct links to melatonin
levels, other types of depression have not responded well to melatonin
treatment. Exaggerated depressive symptoms have been reported in
some cases of depressed patients receiving daytime melatonin supplements.
Melatonin has increased psychotic behavior in some schizophrenic
patients.
Deficiency: Melatonin deficiency is associated with
the following: menstruation, aging, autism, epilepsy, Down's syndrome,
Alzheimer's disease and cerebral palsy.
Sources: Melatonin is a hormone manufactured by serotonin
and secreted by the pineal gland. It is an indole, like the simple
amino acid, tryptophan.
Precautions: There are no known serious side effects
to regulated melatonin supplementation. Some people may experience
vivid dreams or nightmares. Overuse or incorrect use of melatonin
could disrupt circadian rhythms. Long-term effects have not been
well studied. In rats, melatonin decreases T4 and T3 uptake levels.
Melatonin can cause drowsiness if taken during the day. If morning
drowsiness is experienced after taking melatonin at night, reduce
dosage levels. In some cases of depression, daytime doses of melatonin
can increase depression.
May be contraindicated for those with autoimmune disorders and
immune system cancers (e.g., lymphoma, leukemia).
Because melatonin suppresses corticosteroid activity, those who
are taking corticosteroids for anti-inflammatory or immune suppressive
purposes (e.g., transplant patients) should exercise caution with
melatonin supplementation.
Melatonin could interfere with fertility. It is also contraindicated
during pregnancy and lactation.
Lack of sleep and insufficient exposure to darkness may suppress
natural production of melatonin.
Dosage Ranges and Duration of Administration: Official
dosage ranges have not yet been set for melatonin supplementation.
Sensitivity to melatonin may vary from individual to individual.
For those especially sensitive to it, lower doses may work more
effectively than the standard amount. Higher doses could cause anxiety
or irritability.
For treatment of insomnia, a dose of 3 mg taken an hour before
bedtime is usually effective, although dosages as low as 0.1 to
0.3 mg may improve sleep for some people. If 3 mg a night is not
effective after three days, try 6 mg one hour before bedtime. An
individually effective dose should produce restful sleep and no
daytime irritability or fatigue.
For treatment of jet lag, take 5 mg of melatonin one hour before
bedtime upon arrival at new location; repeat for the first five
days. Long-term melatonin supplementation should not be carried
out without a health care provider's supervision.
INTERACTIONS
Clonidine; Methoxamine
Melatonin impaired the efficacy of both methoxamine and clonidine
by relaxing vascular smooth muscle through an undetermined mechanism
in an ex-vivo experiment using thoracic aorta excised from male
rats (Weekley 1991). It is not known whether exogenous melatonin
can antagonize the effects of methoxamine and clonidine in humans.
Desipramine; Fluoxetine
In an experimental rat study, exogenous melatonin (0.25 mg/kg/day)
abolished the antidepressant effects of desipramine and fluoxetine
possibly through interference with tryptophan-2,3-dioxygenase activity
(Walsh and Daya 1998). More research is needed to determine if exogenous
melatonin counteracts the effects of antidepressants in humans.
Tamoxifen
Preliminary research suggests that tamoxifen plus high-dose
melatonin may be of benefit in patients with metastatic solid tumors
or breast cancer (Lissoni et al. 1995A; Lissoni et al. 1996). More
research is needed to confirm these effects.
Triazolam
The combination of melatonin (100 mg/day) with triazolam improved
subjective sleep quality in healthy subjects (Ferini-Strambi et
al. 1993). Another case study reported that melatonin (1 mg/day
controlled release) improved sleep quality and enabled a patient
to cease long-term benzodiazepine therapy (Dagan et al. 1997). |
