- MELATONIN (PHYTOMELATONIN)
:
Melatonin is a hormone made
by the brain's pineal gland that helps regulate your body's internal
clock and may help trigger the onset of sleep. It is used by some people
to help with sleep disorders. Melatonin supplements are not available
in Ireland but can be obtained through the internet.
What is it good for?
Melatonin helps to regulate the body's wake-sleep cycle in people who
can't perceive daylight. Some studies found that it may help with sleep-wake
disorders in people with mental retardation and autism. Several studies
found melatonin may ease insomnia in elderly people with melatonin deficiency.
A handful of studies suggest that melatonin is moderately effective
for jet lag. In one study, 20 people flew through 12 time zones from
New Zealand to London. Those who took melatonin for three days before
and after the flight found their energy levels and sleep patterns returned
to normal an average of 1.5 days sooner than those who took a placebo
(dummy pill). Human evidence suggests that melatonin, along with chemotherapy
(anti-cancer drugs) may help treat various cancers, and melatonin may
help prevent thrombocytopenia (low platelet levels in the blood) caused
by some types of chemotherapy. But melatonin does not seem to help people
adjust to rotating shift work and it may actually worsen depression.
Although some preliminary studies have shown that melatonin may prolong
the life span of mice and rats, there is no medical evidence that taking
melatonin supplements will slow the ageing process in humans.
How does it work?
The pineal gland is synchronised to the normal 24-hour day, secreting
more melatonin at night and less during daylight, so when you travel
or work the night shift, it may take several days for your internal
clock to adjust. Researchers theorise that you may be able to help the
process along by taking a melatonin supplement at times when it would
be released naturally according to your new time zone or work schedule,
although this can vary from person to person and from day to day. Melatonin
secretion also tapers off as you age, possibly explaining why older
people often have trouble sleeping. Children under three have the highest
amounts; by the time you're 50, you may have about ten times less. No
one knows how melatonin induces sleep, but it might have to do with
the fact that the hormone is largely responsible for lowering your body
temperature at night.
How safe is it?
Melatonin can cause headaches, drowsiness, irritability and reduced
alertness. We don't know the long-term effects of taking this hormone.
If you have purchased melatonin supplements elsewhere, avoid taking
them with alcohol or before driving. Women who are pregnant, breast-feeding,
or trying to conceive should not take melatonin, since it can decrease
their levels of reproductive hormones. Melatonin can increase blood
pressure in people taking the blood pressure-lowering medicine (Nifedipine).
People with high blood pressure should talk with their doctor before
using melatonin. It can stimulate the immune system, so people with
autoimmune diseases such as lupus should steer clear of melatonin.
Who Should Avoid Melatonin?
1. Women who are trying to conceive, are pregnant or are nursing a baby.
Large doses of melatonin may prevent ovulation, and the hormone has
not been tested for effects on the fetus during pregnancy. Melatonin
can be found in breast milk; the effect of large doses on nursing babies
is unknown.
2. People with disorders involving the immune system, such as severe
allergies, autoimmune diseases (like rheumatoid arthritis) or immune-system
cancers (like lymphoma). High doses of melatonin may stimulate the immune
system and may worsen such conditions.
3. Children, who naturally produce high levels of melatonin, should
not take supplements of the hormone. Its effects on them are unknown.
4. People with severe mental illness. High doses given during the daytime
have worsened the symptoms of some patients.
5. People taking steroid medications. Melatonin may counteract the drugs'
therapeutic effects.
6. People under 40 years old. Normal melatonin production declines most
rapidly only after age 40.
7. People taking monoamine oxidase (MAO) inhibitors. Current melatonin
preparations may be contaminated by vasoactive amines.
8. People who don't want to lower their natural production of estrogen,
testosterone and thyroid hormones, which high doses of melatonin will
do.
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