Study Shows Melatonin, Asthma Bad Combo

DENVER--Researchers reported melatonin may not be a good option for asthmatic insomniacs. In a study published in the September Journal of Allergy and Clinical Immunologuy (www.sciencedirect.com), melatonin was shown to promote inflammation, a factor in asthma. And because melatonin is released at night, it may most adversely affect asthmatics with night asthma.

The study involved seven people with nocturnal asthma, 13 with non-nocturnal asthma and 11 healthy controls. After establishing a regular sleep schedule for seven days, patients had blood samples taken while asleep on the eighth night. The samples were then evaluated for melatonin levels. Study subjects were also given lung function tests before falling asleep and after waking up.

Nocturnal asthmatics had the highest melatonin levels and the greatest drop in lung function during sleep. Levels averaged 67.5 pg/mL compared to 61.1 pg/mL in non-nocturnal asthmatics and 53.5 pg/mL in healthy controls. Lung function dropped an average of 18.8 percent in nocturnal asthmatics compared to 5.1 percent in non-nocturnal asthmatics. In healthy controls, lung function increased 1.5 percent during sleep.

"These finding suggest that melatonin naturally produced by people with nocturnal asthma increases inflammation in their airways, leading to worse lung function," said study author Rand Sutherland, M.D., M.P.H., out of the National Jewish Medical and Research Center. "Given that previous work has shown that melatonin promotes inflammation in the cells of both nocturnal and non-nocturnal asthmatics, any person with asthma should be cautious about taking supplements that would further raise his melatonin blood levels."

Sutherland was referring to a 2002 study in which he and colleagues found patients with nocturnal asthma had a cytokine response to melatonin that was greater than that of control subjects or patients with non-nocturnal asthma (Am J Respir Crit Care Med, 166, 8:1055-61, 2002).