Sherry Peng

Vaping is bad. We’ve all heard this from our parents and numerous articles. But why? We’ve all pretty much become numb to the harms of “xyz” because of how often new findings come out describing how some common chemical we eat or action we take can increase our risk of disease or death. Most of us have become desensitized to these findings, and many people have a hard time believing these studies that they may consider as “one-offs.” I won’t cite or mention any such studies, but I will tell you what we know as established facts over decades of understanding. I also will not mention nicotine at all; my research has never touched the discussion of nicotine, and I don’t have enough information to have an opinion about it. This comes as a plus, in case the easy and reasonable question gets asked: “What about nicotine-free vapes?”

More to come on mechanisms of acetaldehyde metabolism, flavorings, limits of research, and specifics of concepts and compounds brushed over here.

Intro to Propylene Glycol and Vegetable Glycerin

E-cigarettes or vapes vary drastically in their exterior and interior appearances, depending on the brand and model, but there are major similarities. The base liquid formula of all e-liquids consist of propylene glycol (PG) and vegetable glycerin (VG). The difference in formulas lies in their specific ratio. They are both humectants (they retain moisture well), and are often used in lotions, other personal care products, and food preservatives. PG actually is used in fog machines to produce dense clouds. Both of them are classified as safe by the FDA; VG is Generally Recognized As Safe (GRAS) for use in food, and PG is GRAS for use as a food additive. While they have this nice certification, this only applies to the ingestion of PG and VG; there are no established safety or toxicology guidelines for the inhalation of these compounds. The drastic variation in pathways (ingestion vs inhalation) is substantial, considering the many differing functions and protections encompassed in the respiratory vs digestive systems.

Next, these compounds are heated up to a typical, 400-500 F, and at times, 600-700 F, via a metal coil that heats up a cotton wick absorbed with some e-liquid. The metal coil is wrapped around this absorbent wick to dissipate heat quickly to aerosolize the liquid as soon as you inhale through the mouthpiece. Essentially, you are heating something from room temperature to an extreme temperature in less than a second. Unfortunately, PG and VG thermally degrade; one of the main byproducts includes acetaldehyde. Acetaldehyde is the byproduct of drinking alcohol (ethanol) that makes alcohol consumption carcinogenic. (It is not the actual ethanol that is carcinogenic). In short, your body naturally converts the ethanol to acetaldehyde via the alcohol dehydrogenase (ADH) enzymes. Acetaldehyde is eventually metabolized into a less harmful compound via the aldehyde dehydrogenase 2 enzyme, but this process may be slowed from a deficiency in this enzyme and/or excess acetaldehyde flooding the enzyme. Any delay that allows acetaldehyde to sit gives more time for it to absorb into your tissue and bind with DNA and proteins, which can lead to mutations and oxidative stress.

What we know and don’t know

With decades of solid basic science and clinical research over centuries consumption of alcohol, we have established that the acetaldehyde from alcohol consumption is a known Group 1 carcinogen, aka we know with certainty that drinking alcohol directly causes cancer. These effects are clear with the large numbers of cancer-related deaths over many decades from long-term drinking (linked to: liver, mouth, throat, larynx, esophagus, breast, and colorectal cancer).

Now, it’s vital to be transparent and establish a lack of understanding with acetaldehyde toxicology in e-cigarettes via a completely different ingestion pathway. The boom of vaping came shortly after the launch of Juul in 2015. A small fraction of people had vaped before this, but Juul inarguably started the global fight to take over this gigantic market. Social media virality began around 2016/2017, hooking teens. It has been barely a decade since then. In the most extreme case, people who have been vaping since Juul’s conception have just passed 10 years of use. In many cases, considering a reasonable spread of trends into the younger population, many people have been using for a couple to several years. This is far from long enough time to have established any convincing and accurate testimony of both short-term and long-term effects and risks.

For reference, in 1964, the U.S. Surgeon General officially reported that traditional cigarette smoking caused lung cancer, 80+ years after cigarettes became popular. This was also about 30 years after scientists first started noticing, investigating, and suspecting links of smoking to cancer. To counter, technology and research methods were not as advanced and efficient decades ago. Regardless, the human body is incredibly and insanely amazing at keeping us alive. Countless systems and protective mechanisms are constantly working together to shield us from death. This makes it extremely difficult to identify devastating diseases until it has unfortunately already started to hit us.

Vaping vs Traditional Cigarettes

Similar to the latter, there is no objective answer to the question: Is vaping or traditional cigarettes worse for you? The question is similar to comparing apples and pears.

There are unique carcinogens released when smoking a cigarette, associated with the burning of tobacco. Heavy metals, acetaldehyde, formaldehyde, and more are also released. E-cigarettes mostly release their constituents, PG and VG and flavorings, and byproducts, acetaldehyde, formaldehyde, and acrolein. Flavorings are the same compounds used in candies and other flavored foods; they are FDA approved for ingestion, not for inhalation. This is perhaps the biggest misconception about flavorings. Most people assume they are harmless because we already consume them often. For example, we apply lotion to our skin, but we understand that ingesting it is obviously not the same. Fundamentally, the safety mechanisms differ in different parts of our body. What our strong stomach acid and mighty liver can digest with ease may become a painful struggle in the lungs.

The next important discussion point is ease of use between products. Cigarettes are more taboo now, culturally and due to their strong, unpleasant odor. You don’t see many people lighting a cigarette in a classroom or public building. It is just too noticeable. In contrast, vaping was designed to be easy to hide and enjoyed anywhere at anytime. There is no burnt smell, rather there is a familiar and maybe nostalgic fruity smell. Though potent, it’s still far more tolerable than the black smoke produced by burning tobacco. This has led to many adolescents consistently vaping in classrooms, at work, at home, and pretty much wherever they are at the moment.

More use = more levels of compounds = higher risk of “x” unknown future disease

We might not have pointed a decisive finger at what this “x” disease may be, but it is a matter of time before we find out the hard way through tracing deaths. Perhaps, your conclusion leads you to believe one out of the two is less detrimental than the other. To me, they sort of balance each other out with their toxicity of their makeup and their frequency of use. However, with what I know, I currently believe e-cigarettes are overall more harmful based on the shocking usage amounts documented.

Conclusion

The lung protects you from many chemicals in the air. Were this not the case, frequent exposure to everyday pollutants or smoke would quickly lead to disease or death. However, its designated purpose in the body is to filter oxygen and mild, low amounts of debris; it can also filter out more toxic chemicals if infrequent. The lung is an air filter that is supposed to last a lifetime; you get one pair. Flooding the lungs with vape juice and carcinogens may not have yielded indisputable proof of harm yet, but the outcomes are unlikely to be anything but harmful, varying only in severity. Our understanding is further limited by the challenges of translating basic science into human biology and the ethical boundaries that restrict clinical research. I hypothesize that vaping will be even more harmful than drinking alcohol; given that ingested acetaldehyde is already clearly associated with cancer, the more vulnerable respiratory system is likely at even higher risk.