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Asthmatics Cautioned About Melatonin

Study finds sleep supplement may worsen condition at night

By Steven Reinberg HealthDay Reporter

MONDAY, Sept. 8 (HealthDayNews) -- Melatonin, a naturally occurring
hormone that helps regulate the body's circadian rhythms, may make
asthma worse at night, a new study finds.

"We found that patients who have nocturnal asthma have higher melatonin
levels than patients who do not have asthma," says study author Dr. Rand
Sutherland, an assistant professor of medicine at the National Jewish
Medical and Research Center in Denver. "Higher levels of melatonin were
associated with a greater worsening of lung function overnight."

Melatonin is produced by the pineal gland in the brain, and many people
take supplemental melatonin to help them sleep and to combat jet lag.

In the study, Sutherland and his colleagues recruited seven patients
with nocturnal asthma, 13 patients with non-nocturnal asthma, and 11
patients without asthma. While the patients slept, the researchers took
blood samples every two hours.

Sutherland's team also measured lung function before the patients went
to bed and again after they woke up, according to their report in the
September issue of the Journal of Allergy and Clinical Immunology.

Results showed the patients with nocturnal asthma had the highest levels
of melatonin and the biggest drop in lung function. Among those with
nocturnal asthma, levels of melatonin were an average of 68 picograms
per milliliter (pg/ml), compared with 61 pg/ml for patients with
non-nocturnal asthma and 54 pg/ml for patients without asthma.

In addition, among patients with nocturnal asthma, lung function dropped
an average of
19 percent compared with 5 percent in patients with non-nocturnal
asthma. Among non-asthmatic patients, lung function increased about 2
percent.

In other experiments, melatonin has been shown to rev up inflammatory
cells and make them produce cytokines, which are inflammatory markers,
Sutherland notes. Sutherland speculates that "high melatonin levels may
be one way in which the worsening of nocturnal asthma is regulated."

"These findings raise concern that high melatonin levels may play a role
in making asthma worse at night, and therefore people with asthma should
avoid taking supplemental melatonin," Sutherland advises.

Charles Irvin, a professor of medicine and director of the Vermont Lung
Center at the University of Vermont, comments that "this is a very
important paper and could be a very exciting development."

This study is the first real attempt to find out the cause of nocturnal
asthma, he says: "The conclusion by Sutherland that patients with asthma
should be cautious about using melatonin is just right."

Patients are desperate to find non-pharmaceutical treatments, Irvin
says, but many of the alternatives are not benign. Many like melatonin
are very powerful, he adds. And people need to be careful about how they
use these supplements.

"Patients with mild asthma may try melatonin, but if their asthma gets
worse, they should stop it right away. However, people with nocturnal
asthma should avoid taking melatonin altogether," Irvin cautions.

More information

To learn more about asthma, visit the American Academy of Allergy,
Asthma and Immunology or the American Lung Association.

SOURCES: Rand Sutherland, M.D., M.P.H., assistant professor, medicine,
National Jewish Medical and Research Center, University of Colorado
Health Sciences Center, Denver; Charles Irvin, Ph.D., professor,
medicine, and director, Vermont Lung Center, University of Vermont,
Burlington; September 2003 Journal of Allergy and Clinical Immunology

Copyright © 2003 ScoutNews, LLC. All rights reserved.

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