The Truth About Diacetyl

Welcome to this week’s installment of our Knowledge is Power blog series. Last week we talked about what’s in E-Juice and its safety. Originally the Diacetyl information was going to be included in the E-Juice – What’s Inside blog edition, but in researching this topic, it became so in depth that we felt it was important to address this subject specifically. I would like to mention that while there are multiple news articles discussing this topic, each of the articles I read referenced the studies and articles I will share with you below. Thank you for joining us this week as we discuss Diacetyl and e-juice.

Wisegeek 1 gives this definition of diacetyl:

A naturally occurring chemical that is produced as a byproduct of yeast during the fermentation process. Used in a wide variety of food products, it is best known as a flavoring in microwave buttered popcorn. Most recently, diacetyl has earned a bad name for being the probable cause of several popcorn factory workers developing what has been dubbed ‘popcorn lung’, or bronchiolitis. This is a rare and serious fixed obstructive lung disease.

In the 1990’s, factory workers in a microwave popcorn plant contracted bronchiolitis, also known as ‘popcorn lung’. It was generally believed that this was the result of inhaling a powdered form of diacetyl, in very high concentrations, which is used in the butter flavoring for the popcorn.

While it is generally believed that the cause of popcorn lung was inhalation of powdered diacetyl, this has yet to be proven, as we will see shortly in the information provided by the CDC. It is important to note that the FDA has posted the following statement about the consumption of diacetyl on their website 2,

Diacetyl is added to some foods for flavoring purposes. It is metabolized in mammals, is of low acute toxicity, and the no-adverse-effect level is estimated to be less than .3mg. There is no evidence on the available information on diacetyl that demonstrates or suggests reasonable grounds to suspect a hazard to the public when they are used at levels that are now current or that may reasonably be expected in the future.

The FDA has listed Diacetyl on their Generally Regarded as Safe (GRAS) list of food additive products, yet they have not made a statement regarding the safety of the inhalation of diacetyl in vapor form. As mentioned above, it hasn’t been proven that diacetyl was the cause of the popcorn-lung, as seen by the article published by the CDC 3 to address their views on diacetyl titled Flavorings-Related Lung Disease in which they state

Diacetyl is a chemical that was found to be a prominent volatile constituent in butter flavoring and air at the microwave popcorn plant initially investigated. Workers in microwave popcorn manufacturing are exposed to many materials besides diacetyl. Thus, initial studies in a total of 6 microwave popcorn plants were not able to definitely determine if diacetyl exposure contributed to lung disease or was a marker for other hazardous substances that contributed to disease. Current evidence, however, points to diacetyl as one agent that can cause flavorings-related lung disease. While other flavoring ingredients may also play a role.

Meaning, while they cannot prove that diacetyl was the cause of the disease, they do consider it a primary area of concern. The diacetyl inhaled by these factory workers was in powder form, used to add a buttery flavor to the microwave popcorn they were producing. However, when vaping there is obviously no powder being inhaled, so does this concern relate to vaping?

It may not be common knowledge, but diacetyl is a common ingredient in tobacco, and has been for over 50 years. Meaning, those who have been smoking cigarettes, have been inhaling diacetyl this whole time. The Critical Reviews in Toxicology 4 group conducted a study simply titled Diacetyl where they concluded,

Diacetyl exposures from cigarette smoking far exceeded occupational exposures for most food/flavoring workers. This suggests that previous claims of a significant exposure-response relationship between diacetyl inhalation and respiratory disease in food/flavoring workers were confounded. Further, smoking has not been shown to be a risk factor for bronchiolitis (popcorn lung).

To summarize their findings, they found that the levels of diacetyl in tobacco were significantly higher than those found in the factories where the popcorn lung was contracted, bringing into question the diacetyl as the cause of the condition. Further, they found that smoking cigarettes, regardless of the higher levels of diacetyl has not been shown to cause popcorn lung. Looking at e-juice in relation to tobacco levels of diacetyl the Nicotine & Tobacco Research 5 group conducted a study Evaluation of Electronic Cigarette Liquids and published these results, “The purpose of this study was to evaluate sweet-flavoured electronic cigarette (EC) liquids for the presence of diacetyl (DA). DA was found in 74.2% of the samples. They were lower than the strict safety limits for occupational exposure and 110 times lower compared to smoking respectively.” This tells us first, that there is diacetyl in analog cigarettes at 110 times higher levels than those found in the e-juices they studied. Secondly, this tells us the amounts they found in the e-juice were within the safety limits of exposure.

To summarize, studies like those conducted above show that there is a significantly higher amount of diacetyl exposure from smoking than there is in the factories where the production workers got sick, presumably (but not proven to be) due to exposure to diacetyl inhalation. There are also no documented cases of popcorn-lung being developed from smoking. That being said, when you buy from Mt Baker Vapor we use the highest quality, finest ingredients from right here in the US, which means we can make sure that they are all diacetyl free. We choose not to purchase from suppliers that use it in their flavoring.

As always, I encourage everyone to educate themselves. Read the studies and information listed in the references below, and learn more about the data surrounding the subject of diacetyl. Come back next week when we look at the subject of Nicotine absorption levels and how they are affected by what we use to vape, and the way we vape. Until then, we look forward to your questions and comments. Vape on!

Written by: Michelle Harnden

12/11/15 Revision:

A recent article in the Harvard Gazette presented a new study related to Diacetyl in e-juice. You can read that entire study here: http://ehp.niehs.nih.gov/15-10185./

Vaping researcher Dr. Konstantinos Farsalinos has analyzed the findings of this study, and presents his own analysis here: http://www.ecigarette-research.org/research/index.php/whats-new/whatsnew-2015/236-da2