E-Cigarette Reviews and Rankings

Harvard Study Finds Flavorings Linked to Popcorn Lung Diseases in E-Cigarette Vapor

Researchers at Harvard T.H. Chan School of Public Health recently tested over 50 types of flavored e-cigarettes and e-liquids for diacetyl, acetoin and 2,3-pentanedione – food flavorings linked to bronchiolitis obliterans ,or popcorn lung disease – and detected their presence in two thirds of the samples.

e-liquidAlthough diacetyl and its two very similar substitutes are considered generally safe for consumption, that actually only applies to ingestion. Inhaling these widely used flavorings has been linked to a potentially deadly respiratory condition known as bronhiolitis obliterans. It causes the bronchioles (small airway branches in the lungs) to compress and narrow due to the forming of fibrosis (scar tissue), which severely diminishes the breathing capacity of sufferers.

Diacetyl and acetoin were widely used as e-liquid ingredients a few years ago, for their strong buttery taste, but due to concerns in the vaping community and a number of scandals, particularly the case of luxury e-liquid company Five Pawns, most brands announced they were going diacetyl free. However, the lack of any kind of regulations in the industry left consumers with the sole option of trusting in the word of these companies, with no real way to verify their claims.

According to a disturbing study published in the Environmental Health Perspectives journal, a wide number of flavored e-liquids and e-cigarettes still contain diacetyl, acetoin or 2,3-pentanedione. Scientists at Harvard T.H. Chan School of Public Health tested 51 different juices and e-cigarettes and discovered the presence of at least one of these flavorings in a whopping 47 of them. Diacetyl was detected above the laboratory limit of detection in 39 of the flavors tested, acetoin was present in 46 of them and 2,3-pentanedione was found in 23 of the samples.

“Recognition of the hazards associated with inhaling flavoring chemicals started with ‘popcorn lung’ over a decade ago. However, diacetyl and other related flavoring chemicals are used in many other flavors beyond butter-flavored popcorn, including fruit flavors, alcohol flavors, and, we learned in our study, candy-flavored e-cigarettes,” said lead author Joseph Allen, assistant professor of exposure assessment sciences. Surprisingly, diacetyl was also detected in “tobacco” and “menthol” flavored e-cigarettes, although these are not on the Occupational Safety and Health Administration’s (OSHA) list of flavors that likely contain the chemical.

Researchers performed the testing by inserting e-cigarettes into a sealed chamber attached to a lab-built device that drew air through the e-cig for eight seconds at a time with a resting period of 15 or 30 second between each draw. The resulted vapor was then analyzed.

“Since most of the health concerns about e-cigarettes have focused on nicotine, there is still much we do not know about e-cigarettes” said study co-author Dr David Christiani, Professor of Environmental Genetics. “In addition to containing varying levels of the addictive substance nicotine, they also contain other cancer-causing chemicals, such as formaldehyde, and as our study shows, flavoring chemicals that can cause lung damage.”

Unfortunately, researchers failed to mention that diacetyl and acetyl propionyl are also present in tobacco cigarette smoke, in levels 100 and 10 times higher than the analyzed samples. As far as harm reduction is concerned, e-cigarettes are still the much safer choice.

Reading through the actual study, I was unable to find out how many, if any, of the tested samples contained one or more of the three flavorings in doses that exceed the safely limits recommended by the National Institute for Occupational Safety and Health (NIOSH), which is actually a very important detail. However, the mere presence of diacetyl and/or its frequently used substitutes is disturbing enough.

No brand names are revealed in the Harvard study, although the paper mentions that the tested samples came from “leading brands”.

The research was supported by an NIH/NIEHS Center grant.

In a recent analysis of this study, Dr. Konstnatinos Farsalinos notes that the detected levels of harmful flavorings are extremely low. “In many cases, levels of these compounds are absolutely minimal, and it is NOT expected to raise any concerns about human health effects,” he says. “In conclusion, the article is creating false impressions and exaggerates the potential risk from diacetyl and acetyl propionyl exposure through e-cigarettes. They failed to mention that these chemicals are present in tobacco cigarette smoke and violated a classical toxicological principle that the amount determines the toxicity and the risk.”

2 Comments/Reviews

  • bill says:

    acetoin, not acrolein, was discussed in the article. Acetoin is a butter taste, Acrolein a bitter taste and is produced by burning glycerin or cigarettes.

    Get your summaries right!

    • karen says:

      I had been smoking blu ecigs for approx. 2 months and became sick suffering from lethargy, Headaches, extremely large welts all over my face, Bad metallic taste everyday in my mouth, bleeding gums worsening everyday and a white tongue which was thrush. I was being poisoned by the toxins that were in the tank with no warnings labeled on the box. My face is still healing yet looks like it has been burnt with no satisfaction from the company. Also tank was leaking onto my lips Looking for help from attorneys to help resolve these issues

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