Holistic hormone: melatonin is more than a sleep aid.(Wellness: supplements and functional foods)

Because it only comes out at night, melatonin is sometimes referred to as the "Dracula" of hormones. Sunset triggers heightened melatonin secretion from the pineal gland; these levels subside with sunrise, thereby regulating periods of sleep and wakefulness.

When this biological clock, known as circadian rhythm, is disrupted, sleeping can be difficult, and supplemental melatonin may help improve sleeping patterns. Other credits to melatonin's name include effects in anti-aging, brain health, cancer and obesity.

Sleep

Melatonin supplements tend to be used mainly for improving sleep, which is a concern in the United States. According to the National Sleep Foundation's 2002 "Sleep in America" poll (available online at www.sleepfoundation.org), more than half of American adults have difficulty falling asleep or staying asleep at least a few times a week.

Melatonin supplements may be of use for certain insomnias and circadian rhythm sleep disorders, as reported in the November 2004 issue of the journal Sleep Medicine. Specifically, melatonin supplements taken at the same time each night improve sleep in East-bound travelers, according to the January 2004 Journal of Applied Physiology. Additional research published in September 2004 in Sleep showed improved sleep in 40 healthy men who took melatonin supplements.

In addition to improving sleep in healthy subjects, melatonin may offer benefits for insomniacs since this group is known to produce low levels of melatonin, according to the December 2002 issue of the journal Psychiatry Research. Melatonin supplements at doses of 5 milligrams per day (mg/d) proved beneficial to children with chronic insomnia, according to a study presented in the November 2003 Journal of the American Academy of Child & Adolescent Psychiatry.

The same dosage, however, did not improve sleep in subjects with age-related sleep disorders, as reported in the March 2003 issue of Age and Ageing. Interestingly enough, however, elderly subjects participating in a Hawaiian study experienced improvements in sleep quality with a lower dosage of 1 mg/d.