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Melatonin
is a natural hormone that regulates the human biological clock.
Double-blind
research with young adults has shown that melatonin facilitates
sleep. Another study of healthy, young adults reported that
melatonin significantly shortened the time needed to go to sleep,
reduced
the number of night awakenings, and improved sleep quality.
Other researchers reported the time needed to get to sleep was
reduced
with melatonin.
Melatonin is
also helpful in relieving symptoms of jet lag. One double-blind
trial, involving a sample of international flight
crew members taking either melatonin or a placebo for three
days before and five days after an international flight, found
that
melatonin significantly reduced symptoms of jet lag and resulted
in a quicker recovery of preflight energy levels and alertness.
Less than 1
mg of melatonin has lowered pressure within the eyes of healthy
people, but
studies have not yet been published on
the effects of using melatonin with people who have glaucoma.
Melatonin might help some people suffering from depression.
A small double-blind study suggested that supplementation with
small
amounts of melatonin (0.125 mg taken twice per day) may reduce
winter depression. People with major depressive disorders sometimes
have sleep disturbances. Melatonin has been shown to be effective
at improving the quality of sleep of people with major depression.
However, because of the possibility that melatonin could exacerbate
depression, it should only be used for this purpose, under a
doctor’s
supervision.
When some people
take melatonin to treat sleep disorders, chronic tension headaches
are relieved.8 Melatonin has also relieved cluster
headaches in double-blind research.9 Some researchers have suggested
that melatonin’s role in regulating core body temperature
may be responsible for preventing cluster headaches, which
have been reported to be triggered by increased body heat.
Melatonin also
regulates immunity. One group of doctors reported two successfully
treated
cases of sarcoidosis that it attributed
to melatonin’s immune-modulating effect. Also, because
of its effects on the immune system, melatonin has been given
to people with cancer in many research trials. Low blood levels
of melatonin are associated with an increased risk of uterine
cancer. Melatonin has significantly reduced the level of prostate
specific antigen (PSA, a marker for cancer) in prostate cancer
patients. Melatonin inhibits breast cancer cells in test tubes
and has put some women with breast cancer into remission in
preliminary research.Melatonin supplementation has improved
disease-free
survival in people with melanoma and increased survival in
people with brain cancer and lung cancer. Melatonin exerts
anti-inflammatory
activity that may be responsible for its anticancer properties.
In a double-blind
trial, people who had difficulty sleeping as a result of tinnitus
were better able to sleep if given 3 mg melatonin
per night for one month rather than a placebo. Although melatonin
did not reduce overall symptom scores for tinnitus, people in
this trial with higher symptom scores did appear to obtain some
benefit.
Melatonin supplementation
may be helpful in treating epilepsy; 5–10 mg of melatonin
taken at bedtime reduced the frequency of seizures and improved
sleep in a group of children with epilepsy
in a small, preliminary trial. However, in a group of children
suffering from neurological disorders, 1–5 mg of melatonin
per night led to an increase in the rate of seizures. Children
with a seizure disorder called “myoclonus” were
reported to have been cured by supplementing with 3–5
mg of melatonin per day in a preliminary trial. Until more
is known, children
with neurological conditions should take melatonin only under
medical supervision.
Melatonin may
be useful in the treatment of fibromyalgia. In a small, uncontrolled
preliminary study, 3 mg of melatonin at
bedtime was found to reduce tender points associated with this
disorder. Pain and fatigue improved only slightly.
Children with Angelman’s syndrome (a rare, genetic disorder
characterized by severe mental retardation, seizures, and sleep
disturbances) may benefit from low amounts of melatonin. In an
uncontrolled study, children with Angelman’s Syndrome
who took 0.3 mg of melatonin one-half to one hour before bedtime
had
significant improvement in nighttime sleep patterns and a reduction
in movement disturbances during sleep.
Animal studies
indicate that melatonin secretion may regulate cardiovascular
activity,blood pressure, and blood flow
to the brain. In healthy young men, oral administration of
1 mg of melatonin significantly reduced blood pressure and levels
of stress hormones within 90 minutes. To date, no clinical
trials
in humans have tested the efficacy of melatonin for hypertension.
Melatonin
is produced by the pineal gland, located within the brain. Levels
of melatonin in the body fluctuate
with the cycles of night and day. The highest melatonin levels
are found at night. Melatonin is present in foods only in trace
amounts.
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