June 23, 2000 -- The results of a new study could put millions of people to sleep -- in a good way. Canadian researchers have found an important connection between levels of the hormone melatonin in the brain and the inability to get a good night's sleep. Their findings may be the key to restful nights for the one in 10 people who suffer from insomnia.
The human body naturally secretes melatonin at nighttime. But as people age, natural melatonin levels decrease, sometimes causing interrupted sleep. When this happens, dietary supplements of melatonin -- purchased at pharmacies or health food stores -- can restore normal sleep patterns, the researchers found. Their first-of-its kind study was presented recently at the annual meeting of The Endocrine Society in Toronto.
"Most older people have [below-normal] melatonin levels at nighttime in their blood, and many of these people have insomnia -- which means they awaken and have trouble falling back asleep," researcher Richard J. Wurtman, PhD, tells WebMD. "For these people, low doses of melatonin are highly effective in restoring normal sleep efficiency." Wurtman is a professor in the brain and cognitive science department at Massachusetts Institute of Technology in Cambridge.
Wurtman and colleagues looked at 30 people age 50 and over, half of whom had insomnia. They found that all 30 participants experienced low blood melatonin levels at night, which shows that melatonin deficiency does not always cause insomnia. The study participants were given either a placebo or one of three doses of melatonin, ranging from 0.1 to 3.0 mg. "All three doses of melatonin improved sleep in the insomniacs, but only the middle dose of 0.3 mg restored sleep to normal," Wurtman says.
That's the ideal dose, he says. But the researchers found that insomniacs often take doses that are 10 times higher than their body requires, making the melatonin less effective.
"This demonstrates the need for doctors to work with their patients to find the correct dose of melatonin that raises the blood melatonin level to its normal range, but does not raise the level above [that] range," Wurtman says.