Washington, March 14 : Think twice before having artificial butter flavoured popcorn the next time - for a new study has found that exposure to a chemical called diacetyl, a component of artificial butter flavouring, can be harmful to lungs.
Scientists at the National Institute of Environmental Health Sciences (NIEHS), part of the National Institutes of Health, found that exposure to diacetyl can cause a serious condition that can lead to obliterative bronchiolitis or "popcorn lung."
Experiments showed that mice that inhaled diacetyl vapors for three months developed lymphocytic bronchiolitis-a potential precursor of obliterative bronchiolitis.
None of the mice, however, were diagnosed with the more-serious disorder.
Obliterative bronchiolitis is a life-threatening lung disease that has been detected in workers who inhale significant concentrations of the flavoring in microwave popcorn packaging plants.
"This is one of the first studies to evaluate the respiratory toxicity of diacetyl at levels relevant to human health. Mice were exposed to diacetyl at concentrations and durations comparable to what may be inhaled at some microwave popcorn packaging plants," said Daniel L. Morgan, Ph.D., head of the Respiratory Toxicology Group at the NIEHS and co-author in a release on the study.
Although exposure of laboratory animals by inhalation closely duplicates the way humans are exposed to airborne toxicants, the study points out that some anatomical differences between the mice and humans may account for why the nasal cavity of mice is more susceptible to reactive vapors than that of humans. Another reason may be that mice breathe exclusively through their noses.
The researchers also speculate that the extensive reaction of diacetyl vapors in the nose and upper airways of mice may have prevented toxic concentrations from penetrating deeper in the lung to the bronchioles or tiny airways where obstruction occurs in humans.
When the mice were exposed to high concentrations of diacetyl using a method that bypasses the nose, the researchers found lesions partially obstructing the small airways. More studies are under way to determine if these lesions progress to OB in mice.
The authors conclude that these findings suggest that workplace exposure to diacetyl contributes to the development of obliterative bronchiolitis in humans, but said more research is needed.
The study appears online in the journal, Toxicological Sciences.