Melatonin It seems as though every time we turn around there is a new health fad, be it a drug, herb or diet. Within the past 10 years the drug melatonin has hit the market and seems to have made quite a splash with the public and the media. At a time when an estimated thirty to forty million Americans suffer from serious sleep disorders that interfere with their sleep quality and health, many are desperate for an easy solution (Sleep Foundation 1). The media claims that this wonder drug melatonin is the answer to these sleep disorders and also can prevent several illnesses. But is melatonin really safe enough for the public to experiment with? How much is known about what it does and its side effects? These are many of the questions that scientists are currently trying to answer. Listening to claims from the media and consumers it is tough to get the real story about the research scientists are conducting on melatonin.
Melatonin is an effective drug in aiding in sleep disorders. Melatonin was discovered in 1963 by dermatologist Aaron Lerner at Yale University. Lerner found skin lightning properties from the aggregation of organelles containing pigment (melanin) in the skin cells of amphibians. These collections of organelles are called melanosomes.2 His findings were published in the Journal of American Chemistry Society in a paper on melatonin entitled Isolation of Melatonin, the Pineal Gland Factor that Lightens Melanocytes.3 Melatonin is only one of the many hormones produced by our bodies. This specific hormone is produced in the pineal gland, a small pea sized gland located at the base of the brain. To a lesser extent, melatonin is also produced in the retina.4 The pineal gland begins its production and secretion of melatonin at dusk and ceases at dawn.
The pineal gland is not solely responsible for the release of melatonin, it receives instructions from the hypothalamus telling it when to begin and cease. Part of the hypothalamus, called the Suprachiasmatic Nucleus (SCN), tracks the length of day. It is also responsible for the regulation of many chemicals that govern the complicated process of sleep, including melatonin. The SCN controls the sleep-wake cycle and release of melatonin to fit seasonal changes in the amount of daylight.5 Recently, melatonin has hit the market in the form of a pill and is sold in health stores throughout the country. It is sold as a sleeping aid in pill form that claims it cures and prevents sleep disorders and jet lag in some cases.
It has also been called an anti-aging drug that may prevent hypertension, high cholesterol, migraine, and even cancer and AIDS. None of these claims have been proven, but this does not stop consumers from buying and using this drug.6 Melatonin use is not regulated by the government because it is found in some foods.7 Since Aaron Lerners discovery of melatonin there has been much research on what this hormone is responsible for. Since it was thought that melatonin was involved somewhere in sleep, researchers began a study administering a synthetic form of the hormone to subjects, taking note of the effect in had on different stages of sleep. In the early 80s, Dr. Richard Wurtman of the Massachusetts Institute of Technologys Clinical Research Center began giving volunteers what now would be considered a megadose of melatonin (240 mg).
He found that melatonin aided in sleep and later found that as little as a tenth of a milligram can hasten the onset of sleep regardless of the time of day.8 Wurtman is the named inventor on an MIT patent pending on a melatonin-based sleeping pill (the chemical itself can not be patented). He states there is no controversy that melatonin, even in fractions of a milligram, can induce sleep and shift the sleep cycle.9 Attenburrow and associates conducted a double-blind, placebo controlled, cross-over experiment to determine the effect of melatonin on sleep. Fifteen subjects were given .3 mg, 1 mg of melatonin or a placebo. The subjects sleep was continually measured, including both non-REM and REM sleep, over a period of time. Subjects were then given the opposite substance they were administered in the first segment of the study. Research found that melatonin given out in a 1.0 mg dose significantly improved subjects sleep time (the amount of time it took to fall asleep) and their sleep efficiency (the amount of time spent sleeping compared to the amount of time they were in bed) compared to subjects administered the placebo.
Both non-REM and REM sleep were prolonged by the melatonin.10 Over 58% of the blind population have sleep disorders. They have trouble maintaining body rhythms that are in sync with the outside world due to their inability to perceive light. After being given melatonin before bed, several blind subjects improved their sleep-wake cycle to match that of the outside world. It also helped those unable to fall asleep in the morning and in general, all subjects fell asleep faster.11 Ten years ago a study concerning the role of melatonin was done on rats. These animals were placed in total darkness and were given nightly doses of melatonin.
The rats became locked into daily patterns of daily sleeping and nightly scurrying similar to the rise and fall of the sun. After this study, many researchers examined the possibility that melatonin had an effect on sleep cycles.12 In all species studied (even unicellular algae) there is a day and night rhythm.13 Without usual light cues, the bodys biological rhythms will continue, but will fall out of sync with the outside world. This is true of both rats and humans because both species maintain an internalized sleep cycle of 25 hours under these circumstances. If, for example, a human stayed in a cave with no way to determine what the sun was doing, their sleep rhythms will fall increasingly out of sync with the actual occurrence of day and night.14 Jenny Redman and colleagues at La Trobe University in Australia were among the first to demonstrate that administering melatonin to subjects can shift bio rhythms. They exposed rats to constant light conditions and measured their bio rhythms. These rhythms were found to be more in some cases and less than 24 hours in others.
A rhythm more than twenty-four hours is referred to as a free-running bio rhythm. Redman injected melatonin daily into these rats and found that the injections caused a change from the free-running rhythm into a 24 hour rhythm.15 Chronobiologist Benita Middleton and colleagues from the University of Surrey in England wondered if subjects placed in low-light conditions but take melatonin supplements at night would have normal sleep-wake cycles. To answer this, Middleton placed ten male subjects in a dim lit suite for two weeks. Their heart rates, body temperature and other vital signs were monitored. Each took 10 mg of melatonin at eight PM each night.
After the two weeks were up, eight of the ten maintained normal sleep-wake cycles. Two subjects had very fragmented sleep-wake patterns. Middleton commented, Their biological rhythms seemed to have be …