Researchers Break Down Chemicals in E-cig Flavorings, Impact on Lungs

The label may say “cinnamon” or “vanilla” but the true contents of e-cigarette flavorings are acetoin, diacetyl, and other chemical additives that are known to irritate the respiratory tract and impair lung function, according to a collaborative study from western New York scientists.

Senior author Irfan Rahman, Ph.D., professor of Environmental Medicine and part of the Lung Biology and Disease Program at the University of Rochester Medical Center, said the findings suggest that chemical flavorings in e-cigarettes not only cause inflammation but may rapidly impair the critical epithelial cells in the airways, which act as the first defense against infections and toxins. When the epithelial barrier becomes more permeable or leaky due to chemical assaults, life-threatening lung diseases can occur.

For example, volatile flavoring chemicals (such as the butter flavor in microwave popcorn) have been linked to severe lung diseases among workers at food manufacturing plants who were routinely exposed during production, according to the Centers for Disease Control. 

The local study was published by the journal, Applied In Vitro Toxicology.  Janice Gerloff, a technician in Rahman’s laboratory, and Isaac Sundar, Ph.D., a research assistant professor at URMC, worked with chemists and engineers at the Rochester Institute of Technology and the University at Buffalo to study the chemical characteristics of a sampling of flavored liquids used in vape pens, e-hookahs, e-cigars, e-pipes obtained from local vape shops. More than 450 brands of e-cig products with more than 8,000 flavors (including chocolate, menthol, mango, and cotton candy) are on the market, the study said.

Although the Flavor Extracts Manufacturers Association has certified these chemicals as safe, scientists are concerned about consumers inhaling them in high concentrations. Many e-cig flavors also are laced with nicotine. Researchers tested the emissions of flavored liquids and created a “puff profile” and a chemical profile for each flavor. They also treated human lung cells with the vaping chemicals and observed a potent reaction as pro-inflammatory cells transformed lung epithelial cells, making them more vulnerable to injury and illness.

The U.S Food and Drug Administration, Center for Tobacco Products, funded the research.