Artificial butter chemical may harm lungs

BETHESDA, Md., March 14 (UPI) -- Exposure to a chemical called diacetyl, used in artificial butter flavoring, can be harmful to the nose and airways of mice, a U.S. study found.

Scientists at the National Institute of Environmental Health Sciences conducted the study because diacetyl has been implicated in causing obliterative bronchiolitis in humans. Obliterative bronchiolitis is a debilitating but rare lung disease, which has been detected recently in workers who inhale significant concentrations of the flavoring in microwave popcorn packaging plants.

When laboratory mice inhaled diacetyl vapors for three months, they developed lymphocytic bronchiolitis -- a potential precursor of obliterative bronchiolitis. However, none of the mice were diagnosed with obliterative bronchiolitis.

Mice exposed to high concentrations of diacetyl using a method that bypasses the nose resulted in lesions partially obstructing the small airways. More studies are under way to determine if these lesions progress to obliterative bronchiolitis in mice.

"This is one of the first studies to evaluate the respiratory toxicity of diacetyl at levels relevant to human health," study co-author Daniel L. Morgan said in a statement. "

The study was published in the journal Toxicological Sciences.