Melatonin is a hormone produced by the pineal gland located in the brain. It plays a vitally important role in controlling the body's circadian rhythm and, thus, the wake/sleep cycle. Normal melatonin secretion is suppressed by light and stimulated by periods of darkness. Nocturnal secretion of melatonin is at its highest during childhood, and then decreses with age.
Supplemental intake of melatonin has been shown to regulate circadian rhythm in individuals who have disrupted sleep patterns.
Effect on Sleep Patterns
Melatonin is best known for its ability to help regulate sleep patterns and promote a restful night's sleep. Research indicates that low levels of melatonin may be a frequent cause of insomnia in the elderly. A review of several studies suggests that melatonin supplementation can be helpful in inducing and maintaining sleep in patients suffering from insomnia, particularly when the pineal glands own production is very low. Additionally, individuals who have unsual work hours, such as night shift workers, or people experiencing jet lag, in particular those who regularly travel across time zones, may benefit from melatonin supplementation.
Sleeplessness
Studies on the effects of melatonin in patients with insomnia have demonstrated improvements in overall sleep activity. Reported improvements include the ability to fall asleep faster, fewer nighttime awakenings, and increases in sleep efficiency (percent of time asleep to total time in bed). In one study, sleep onset and sleep maintenance were improved in elderly people with insomnia following one week of supplementation. Patients given melatonin fell asleep faster and slept longer than those given placebo.
Jet Lag
Jet lag is due to the desynchronization between various body rhythms and environmental rhythm as a result of traveling across times zones. Individuals with jet lag may experience disturbed sleep, increased irritability, as well as difficulties in falling to sleep and maintaining restful sleep. Melatonin supplementation may help to alleviate or prevent jet lag by helping to speed up the shifting of the body clock from the time zone to the next.
Antioxidant Activity and Effect on the Immune System
In addition to its role in regulating the wake/sleep cycle, melatonin has been shown to posses antioxidant and anti-aging effects.Through its free radical scavenging activity, melatonin helps to protect cells from molecular damage and dysfunction. Cellular damage caused by free radicals is believed to accelerate the aging process and to be the basis for many disease states. Melatonin supplementation has been reported to provide some benefit to individuals who have a high burden of oxidative stress by reducing the severity of illness. Activation of melatonin receptors has been shown to enhance cytokine release in human monocytes. This activity suggests that melatonin may help to support the body's natural resistance to pathogens.
