2000-10-12 08:59:00
CNN

BOSTON, Massachusetts (CNN) -- A new study is lending credence to the popular claim that the hormonal supplement melatonin can help regulate sleep patterns.

Scientists at Oregon Health Sciences University tested the supplement on a small group of blind people. The blind often suffer from sleep disorders because they cannot perceive the daily cycles of light and dark that regulate the body's biological clock.

The researchers found that nearly all of the subjects developed normal sleep patterns after taking melatonin. When given a placebo, their sleep remained erratic. The results were reported in this week's New England Journal of Medicine.

Study participant Clifton Zang was among those who benefited from the melatonin.

"I was having a hard time staying awake during class time," he said. "I'd get up in the middle of the night and then I'd study."

When he took melatonin at around 8 p.m., though, Zang found he was able to get a good night's sleep.

"I got about six and a half hours of sleep and I felt good," he said. "I'm wide awake and ready to go."

The study authors say melatonin could also help people who aren't blind regulate their sleep.

More than 20 million Americans already use it for that purpose, hoping to treat insomnia or jet lag, or lessen the effects of shift work. The supplement is readily available over the counter at health food stores.

But the study authors caution that knowing how much melatonin to take and when to take it are critical to reaping its benefits.

"The concern I have," said researcher Dr. Al Lewy, "is that people have been taking melatonin at the wrong time at the wrong dose for the wrong reasons."

Experts say the best time of day to take melatonin and how much to take depends on the specific sleep disorder. Taking too much at the wrong time could worsen sleep problems instead of helping them.

In the study, patients started out on high doses, then switched to a low maintenance dose once their body clocks had adjusted.

Doctors have long known that melatonin is involved in regulating the body clock. It is a naturally occurring hormone whose levels rise at night and fall during the day.

However, "the hype and claims of the so-called miraculous powers of melatonin several years ago did a great disservice to a scientific field of real importance," Josephine Arendt of the University of Surrey wrote in an editorial accompanying the NEJM study.

This new research, she said, shows "the true potential of melatonin" and how important timing is to treatment.

"Our 24-hour society, with its chaotic time cures and lack of natural light, may yet reap substantial benefits, " she said.

CNN Medical Correspondent Elizabeth Cohen and Reuters contributed to this report.