Little
Sleep Benefit From Melatonin, Study Shows
A
US government review of more than 50 studies on the effect of
melatonin on sleep has found little evidence that the supplement
helps people drift off.
 While
melatonin does aid sleep in a certain group of people whose
biological clocks are out of kilter, researchers found it
does not promote sleep among the most common users of
the supplement - those suffering from jet lag or weary shift
workers.
"A
lot of people take melatonin for jet lag and shift work, but
we found no good evidence to justify the use of melatonin in
this context," says study author Dr. Terry Klassen, director
of the Evidence-Based Practice Center at the University of Alberta
in Edmonton, Canada.
Insomnia
a Major Problem for Americans
According
to the National Institutes of Health,
approximately 40 million Americans suffer from chronic, long-term
sleep disorders each year, and an additional 20 million experience
occasional sleeping problems. Insomnia tends to increase with
age and affects about 40 percent of women and 30 percent of
men.
The
most common sleep disorders are insomnia, sleep apnea, restless
leg syndrome (particularly among elderly people), and narcolepsy,
a condition in which people suddenly fall asleep for short periods
of time even if they are well-rested.
Melatonin
is a hormone found in the brain that helps the body's sleeping
and waking schedule. Typically, melatonin levels rise in the
evening, causing sleepiness, and are lower in the morning to
induce waking.
The
study, which was funded by the National
Institutes of Health's National Center for Complementary
and Alternative Medicine, was published online by the
Agency for Healthcare Research and Quality
(AHRQ).
The
report is the most comprehensive look at the science behind
the claims that melatonin is a beneficial sleep aid, Dr. Klassen
says.
"There
has been a lot of emphasis on individual studies rather than
the overall picture, but when you put it all together, it tells
a more compelling story," he explains.
The
researchers found the quality of the studies varied, with those
that looked at the effects of melatonin on normal sleepers generally
of lower quality than those studies that looked at people with
sleep problems.
Further,
Dr. Klassen notes, all the studies tended to be small and of
short duration, with an average length of a few months, so that
the long-term effects of melatonin could not be assessed.
The
authors also noted that in the studies assessing the benefits
of melatonin for normal sleepers, "there was considerable evidence
of possible publication bias in the selection of the studies
analyzed," they write. "We found a greater number of studies
reporting positive results compared to negative results."
The
one area where melatonin did seem to work was with a group of
people with a condition called "delayed sleep phase syndrome,"
which means that otherwise healthy people have a biological
quirk that prevents a normal sleep cycle. For these people,
Dr. Klassen says, taking melatonin appeared to improve their
sleep.
"Melatonin
helped to reset their biological clock," he says, so that on
average it reduced the time it took them to fall asleep by about
a half-hour.
Dr.
Klassen says that although many people swear that melatonin
works for them when they are suffering from jet lag, the
science simply does not back up these claims.
"It
could be a placebo [inactive substance] effect, or the fact
that sleep disorders vary, and that someone would get better
anyway," he says.
"When
people go into stores, if a bottle of melatonin has the word
'sleep' on it, there is an implied medical claim that they're
going to sleep better, and this report doesn't support these
implied benefits," says Dr. Meir Kryger, author of A
Woman's Guide to Sleep Disorders. "It's a very good study."
This
is exactly why evidence-based studies are so important, Dr.
Klassen says.
"This
is a huge issue, and an area where we should be spending money
to fund rigorous testing of these claims," he says.
Always
consult your physician for more information.
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According
to the National Sleep Foundation,
it is not unusual to have sleep troubles from time to time.
But, if you feel that you do not get enough sleep or satisfying
sleep, you may have insomnia, a sleep disorder.
People
with insomnia have one or more of the following:
-
difficulty falling asleep
-
waking up often during the
night and having trouble going back to sleep
-
waking up too early in the
morning
-
unrefreshing sleep
Insomnia
can cause problems during the day, such as sleepiness, fatigue,
difficulty concentrating, and irritability. A person with insomnia
may also have another sleep disorder such as sleep apnea, narcolepsy,
and restless legs syndrome.
Insomnia
is not defined by the number of hours you sleep every night.
The amount of sleep a person needs varies. While most people
need between seven and eight hours of sleep a night,
some people do well with less, and some need more.
Acute,
or short-term insomnia may not require treatment. But if your
insomnia makes it hard to function during the day because you
are sleepy and tired, your health care provider may prescribe
sleeping pills for a limited time.
The
rapid onset, short-acting medications now available avoid many
of the earlier problems with continuing effects (like feeling
drowsy or groggy) the following day.
Some
medications may be less effective after several weeks of nightly
use, however, and long-term safety and effectiveness has not
yet been established.
Side
effects of sleeping pills (and over-the-counter sleep medicines)
can be a problem, too. Mild insomnia often can be prevented
or cured by practicing good sleep habits.
Treatment
for chronic (long-term) insomnia includes first treating any
underlying conditions or health problems that are causing the
insomnia.
If
insomnia continues, your health care provider may suggest behavioral
therapy or medication. Most medicines that are used for sleep
have side effects and must be used with caution.
It
is not recommended to use over-the-counter sleeping pills for
insomnia. Behavioral approaches to treatment focus on changing
behaviors that may worsen insomnia and learning new behaviors
to promote sleep.
Techniques
such as relaxation exercises, sleep restriction therapy, and
reconditioning may be useful.
Always
consult your physician for more information.
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