What is that caramel flavoured e-cigarette doing to your lungs?

Photo credit: Lindsay Fox via flickr

When Ernst and Young, one of the largest accounting firms in the world, conducted a global survey  as to why people chose to use e-cigarettes, the most common reason was that ‘vapes were less harmful than regular cigarettes’.

However, research conducted by Quan Lu and Joseph Allen, researchers at Harvard University, has revealed that the chemicals used in e-cigarettes have a detrimental effect on the external lining of lungs.  In a previous study conducted at the Harvard T.H.Chan School of Public Health, researchers found that in over 90% of the tested e-cigarettes, two damaging chemicals, namely diacetyl and 2,3- pentanedione, were present in highest quantities, while a range of other chemicals were detected in smaller amounts.

Diacetyl is used as a flavoring agent in foods such as popcorn, candy and caramel. It is used to create a variety of flavours. Previous research shows that while diacetyl is safe to use in foods, it is dangerous when inhaled. Diacetyl was previously linked to a severe lung infection,  bronchiolitis obliterans. It was first observed in people working in surroundings where microwavable popcorn was being processing. The workers who had inhaled this chemical had significantly reduced lung function  and were said to be affected with ‘popcorn lungs’.

Once the link between diacetyl and popcorn lung was established, the chemical 2,3-pentanedione started being used as a substitute.

Thus, Lu (Associate Professor of Environmental Genetics and Pathophysiology) and Allen (Assistant Professor of Exposure Assessment Science) aimed to learn more about these chemicals on lungs, while inhaled by an e-cigarette.  

Researchers used an interesting technique of study that involved exposing the cells of the lung’s outermost layer (called the epithelial layer) to these two chemicals, in an artificial medium that closely resembled the original human air pathway. After exposing the cells to these chemicals for 24 hours, it was found that both chemicals could alter gene expression that could severely affect the production as well as functioning of cilia.

Cilia, the tiny hair-like projections lining the outermost layer of the lungs, help in removing mucus, dust and dirt particles, to allow a free flowing exchange of gases. Damage to the cilia lining can impair lung function in a lethal manner.

It was also observed that exposing the cells to much lower levels of chemicals affected gene expression within 24 hours. This further raises concerns of safety limits for workers exposed to these chemicals.

Joseph Allen voiced his concerns over e-cigarettes users inhaling chemicals that have not been tested for safety adequately. “While most workers are informed about the dangers of inhaling these chemicals, why don’t e-cigarette users receive the same warnings?”, he questioned.

While certain e-cigarette manufacturers are denying using diacetyl and 2,3-pentanedione, Allen questioned their credibility and wanted to know about other chemicals that were being used by these companies.

Euromonitor, a global market research company, estimates the number of adults vaping will reach almost 55 million by 2021. The rise in use of e-cigarettes have probably been exponentially higher in comparison to the investigation required to check potential health problems caused by vape chemicals.

This post was written by Shruti Sundaresan and edited by Ella Mercer.

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