The Many Faces of Melatonin
It’s bedtime, and all you want to do is get to sleep. But,
your mind is racing. You fret over the day’s experiences, and feel
agitated, irritated, and restless. The clock is ticking; you know just how
many hours are left of the night.
You exhaust yourself with worry.
Finally, relief comes and you drift off to sleep. Sleep, glorious sleep.
Then, without warning and for no apparent reason, you are awake... again.
Your mind begins to race; you worry about how tired you will feel when the
alarm clock shrills. Sound familiar? You have insomnia.
Insomnia is on the rise in America. Job, financial, family and
relationship stresses, even global worries now permeate our lives to such
a degree that, according to statistics, only a third of us are getting
anywhere near enough sleep.
Insomnia can be so debilitating that those who suffer from it often
resort to either a prescription or over-the-counter sleep aid. Sleep aids
can provide effective, temporary relief, but some of them, benzodiazepines
for example, are habit-forming drugs.
The hormone melatonin is known chiefly for its role as a sleep aid.
Ample data substantiates that melatonin can induce sleep. Sixty percent of
those who try melatonin report improved sleep quality, falling asleep
faster, and staying asleep longer. In addition, timed-release melatonin
has been shown to help patients wean themselves off of habit-forming
However, research indicates that melatonin may be more than a sleep
aid. New studies indicate that melatonin helps regulate a number of
biological processes, including circadian rhythms, sleep, mood,
reproduction, tumor growth, degenerative brain diseases, and aging.
Experimental evidence suggests that melatonin inhibits the growth of
breast cancer tumors in animals and humans.
In this Hormonal Update we
take a look at the many faces of melatonin.
Melatonin is a hormone produced in the pineal gland. During
the day your body has very little melatonin circulating in your
bloodstream. Melatonin production increases when the sun goes down,
signaling the body that it is time to go to sleep. Melatonin levels then
continue to rise throughout the late evening and into the night, reaching
a peak between 2 and 4 am.
Light plays a key role in the production of melatonin and the
regulation of the sleep wake cycle. Melatonin secretion is driven
predominantly by the amount of light reaching the eyes.
The optimal melatonin production that leads to a good night’s sleep
requires a balance of daylight and dark exposure. Insomnia, for example,
can be caused by an insufficient exposure
to bright daylight can increase melatonin secretion enough to regulate the
sleep wake cycle in people who are having difficulty sleeping.
Light can also interrupt melatonin production. A brief pulse of bright
light, or a series of pulses over a long enough period of time can
abruptly stop melatonin production during the night.
For instance, if you are asleep in a dark room and someone opens the door,
leaving the hall light shining brightly into the room, your melatonin
production can stop, causing your melatonin level to drop quickly. This in
turn can awaken you, and make it difficult for you to fall back to sleep.
Melatonin production varies with age. Generally, at ages 1 to 3,
melatonin levels are very high. Young adults have slightly lower levels.
Then, as we reach midlife and beyond melatonin production begins to
dwindle. However, new studies reveal that this may not always be true. We
now know that even children can have low levels of melatonin and elders
who are exposed to enough daylight can have nearly optimal levels. Studies
have shown that children, adults, and elders can all benefit from
melatonin supplementation if they need it, enabling them to fall asleep
more quickly, sleep longer, and feel better the next day, experiencing
less fatigue and more alertness.
Jet lag is a sleep disorder caused by a disruption in
circadian rhythm due to an alteration in the sleep-wake cycle. Traveling
across time zones, or working night or rotating shifts can create jet lag
like symptoms _____ fatigue, early awakening, headache,
insomnia, irritability, problems with concentration and reduced immunity.
melatonin supplementation has been shown to alleviate many of the symptoms
associated with jet lag and shift work.
Two important new studies, at the Fred Hutchinson Cancer Research
Center in Seattle, and at Harvard Medical Center, have uncovered critical
information about women who work swing and graveyard shifts. They appear
to be at higher risk for breast cancer. In both of these studies, a
compelling link between nighttime light exposure and increased cancer risk
has been documented. According to the Hutchinson study, increased exposure
to artificial light at night, with the likely minimal exposure to bright
sunlight during the day that comes with shift work may increase a woman’s
breast cancer risk by as much as 60%.
Some scientists believe this discovery may be a key piece of the breast
Nighttime light exposure now ranks with other well-known breast cancer
risks, including alcohol consumption, delayed childbirth and use of high
dose birth control pills. In addition, low levels of melatonin have been
associated with abnormally high levels of circulating estrogen, a known
cancer risk. And, women with estrogen receptor-positive breast cancer have
been found to have low melatonin levels.
Melatonin and Breast Cancer
Exciting new studies suggest that melatonin can inhibit the
growth of breast cancer tumors in animals. It isn’t known just yet how
melatonin works against tumor growth, but evidence is mounting that
melatonin supports immunity.
The Nurse’s Health Study discovery of a possible link between breast
cancer risk and swing or graveyard shift work has caused much speculation
in the scientific community. Of the 80,000 nurses who were followed over
the ten-year period beginning in 1988, 2411 were found to have breast
cancer. The women who worked at least three rotating night shifts for
thirty years or more had 36% increased risk of breast cancer when compared
to the women who worked no night shifts at all. Additional studies also
demonstrate a relationship between working nights and breast cancer.
While the scientific basis for this melatonin breast cancer connection
is still in its early stages it is substantial enough to warrant more
investigation. Even though it is still too early in this research to form
a conclusion about melatonin and cancer protection, the data does suggest
that a good night’s sleep is more important than we ever imagined.
Melatonin and the Immune System
One of the most interesting new areas of melatonin research
investigates its effects on the immune system. Evidence suggests that
melatonin receptor sites on immune cells interact with
t-helper and natural killer cells, the cells that help fight illness and
tumor growth. In animal studies melatonin has been shown to restore immune
A potent antioxidant and free radical scavenger, melatonin is both fat
It appears that melatonin can permeate all the cells of the body,
protecting them against free radicals. Free radicals are highly reactive
atoms or groups of atoms that can bind with other compounds in the body
and damage cells.
In one study, older patients who experienced both insomnia and
infections after surgery were found to have significantly low melatonin
secretion levels. Researchers are now taking a look at the value of
melatonin supplementation for these patients - to help induce sleep and
support the immune system postoperatively.
As with all hormones, the circulating level of melatonin is
an intrinsic part of how and why it works. If you are having trouble
sleeping, salivary analysis can monitor your melatonin activity over the
course of twenty-four hours. This can reveal your melatonin production
pattern, and assist your healthcare practitioner in developing and
monitoring a treatment plan for you.
It is important to remember that each person’s hormone profile is
highly unique. What works for one person, may be too much or too little
for another. Assessing and restoring melatonin levels individually can
help you return your body to a natural, healthful rhythm that promotes
deep, restful sleep.