E-cigarette Flavorings Linked to Serious, Irreversible Lung Disease

In a study just published online in the peer-reviewed journal Environmental Health Perspectives, a team of Harvard scientists reveal that candy-flavored e-cigarette liquid contains chemicals that cause the obstructive lung disease Popcorn Lung.

The study, funded by the National Institutes of Health, focused on the chemicals used to flavor e-cigarette liquid. Study results reveal that 75 percent of the 51 flavored liquids tested contain diacetyl and other harmful compounds. The flavors tested included fruit and candy varieties with potential appeal to young people, the Harvard Gazette reports.

Fruit flavor diacetyl, alcohol flavor diacetyl, and candy flavor diacetyl are some of the culprit ingredients associated with the irreversible lung disease, bronchiolitis obliterans, known as Popcorn Workers Lung or Popcorn Lung. Popcorn Lung is an obstructive lung disease in which the bronchioles of the lungs are blocked by the growth of fibrous tissue. The name traces to the illness developed by employees at a popcorn factory in Missouri that made artificial butter flavoring for microwave popcorn. The workers inhaled diacetyl from the flavoring on a daily basis and developed respiratory symptoms and other symptoms, the National Institute for Occupational Safety and Health (NIOSH) reports.

The symptoms of Popcorn Lung (bronchiolitis obliterans) usually occur gradually and become progressively worse. Symptoms include:

  • Coughing (usually without phlegm)
  • Shortness of breath on exertion
  • Fever
  • Night sweats
  • Weight loss
  • Difficulty blowing air out fast and no improvement with asthma medication

Diacetyl, a chemical used to give microwave popcorn and other snacks a buttery flavor, has been associated with the development of bronchiolitis obliterans. Chemicals used to flavor e-cigarette liquid, such as diacetyl, alpha-diketone, 2,3-butanedione, 2,3-butanedione, 2,3-pentanedione, and acetyl propionyl are among the chemicals that may be responsible for flavorings related lung disease.

People who “vape”—the practice of smoking with e-cigarette devices—with flavored e-cigarette liquids regularly inhale diacetyl. E-cigarette users are increasingly popular among teenagers, and although minors cannot buy traditional cigarettes, they can buy e-cigarettes in many states. At the urging of doctors and public health officials, the Food and Drug Administration (FDA) has proposed new regulations that would prohibit the sale of e-cigarettes to minors.

The Harvard researchers tested 51 types of flavored e-cigarettes and liquids for the presence of diacetyl, acetoin, and 2,3-pentanedione, flavoring compounds that the Flavor and Extract Manufacturers Association lists as “high priority,” for respiratory hazard in the workplace, the Harvard Gazette reports. The researchers inserted each e-cigarette into a sealed chamber attached to a device that drew air through the e-cigarette for eight seconds at a time with a resting period of 15 or 30 second between each draw. They then analyzed the air stream.

Dr. David Christiani, of the Harvard T.H. Chan School of Public Health, who was one of members of the research team and was co-author of a paper based on the study, said the e-liquids contained not only the addictive substance nicotine, but also cancer-causing chemicals, such as formaldehyde, and flavoring chemicals that can cause lung damage, according to the Harvard Gazette.