Eggplants Are the New E-Cigs

Youths are always smoking the darndest cancer sticks.

They’d lose their minds if they knew that the most accessible type of E-Cig is an EGGPLANT-Cig.

No, Morpheus, it’s not the “E”, it’s the NICOTINE!!

Tobacco is in the nightshade family of plants.  So are eggplants, tomatoes, potatoes, and bell peppers.  What most rebellious youths don’t know is that the vegetables they despise contain the drug they aspire to smoke.

Luckily for McGruff The Crime Dog, the actual amounts of nicotine in vegetables are very small.

You’d need to eat tons- well, actually half a ton*- of eggplant to absorb the nicotine amount contained in one cigarette or vape cartridge.

Although you could choose to eat that much…

So does the fact that many common vegetables have nicotine mean you’ll get addicted?

Cigarettes are addicting, but vegetables, as far as we know, aren’t.  I mean, I say I’m “addicted” to eggplant parm, but what I mean is WHO COULDN’T LOVE A DISH THAT’S MOSTLY MELTED CHEESE??

Now we just have to figure out how to vape eggplant parm.

Anyway, we’ve established that many common vegetables have a small amount of nicotine that won’t get you addicted.  And these vegetables are closely related to each other within the nightshade family.    Does that mean you can flip it and reverse it, and use nicotine to see exactly how related plants are?

This idea is called “chemotaxonomy”.  In the 80’s, one scientist tried to group the nightshade family according to plants’ levels of nicotine and related compounds.   Here’s the result:

Don’t worry, everyone else was confused too.  Clearly, relying only on chemistry to classify plants was a stretch.  Good thing we figured that one out.

So why exactly didn’t chemotaxonomy work?

Because nicotine actually does stuff!

We often think about the addictive properties of nicotine without thinking of the bad side effects it produces–on insects!

Nicotine is an insect neurotoxin.  And that means that plants that make nicotine in their leaves and fruits can instantly turn a hungry insect into a non-hungry (or dead) insect.  Good for plants, bad for bugs.   The class of insecticides called neonicotinoids are similar to nicotine.

Because nicotine is so good at stopping hungry insects, plants that are prone to insect attack are likely to be adapted to make more nicotine.  This totally messes up chemotaxonomy because it means that the amount of nicotine in a nightshade species doesn’t depend on what it’s related to, just on how tasty it was to insects at some point in the past.

Nicotine also ~~synergizes~~ with other plant defenses in cool ways.  For example,  defenses called “protease inhibitors” mess up insect digestion.  If insects’ digestion is messed up, they will actually eat MORE because they need more food to get the same amount of nutrition.

But if insects eat a leaf containing both protease inhibitors and nicotine, their digestion is messed up AND they don’t want to eat anything.

In conclusion:

Eggplants are drugs!!!!  But mostly for caterpillars, who die.  Youths should still try to vape eggplants because it would be funny.

*Calculation of How Much Eggplant You’d Need to Eat to Equal One Cigarette

You may have heard that 20 lb of eggplant is equivalent to one cigarette.  That statistic is wrong!!  You’d actually have to eat even more eggplant than that.

Cigarettes contain 10 mg of nicotine, and an average smoker takes in 1 to 2 mg of nicotine per cigarette when smoking (source).  Let’s call that 1 mg.

One gram of eggplant contains 2.1 ng, which is 0.0000021 mg, of nicotine, according to Siegmund et. al. (1999).  That means you would need to consume 476,190 g, or 1050 lb, of eggplant to get 1 mg of nicotine.  1050 lb!!

Siegmund et. al. estimate that each person consumes an average of 0.0014 mg of nicotine per day from potatoes, tomatoes, tomato paste, eggplants, and tea combined based on consumption data from 13 European countries and the US.  That’s 1/1000th the amount of nicotine you’d inhale from a cigarette.

Postscript:

“Being a vegan is so dangerous!” –my mother, after hearing the topic of this post

Picture Sources:

McGruff the Crime Dog, kids eating $250 worth of fries, Mad Men Meme, bugs-in-hand gif by Max Litvinov, The Very Hangry Caterpillar

Apologies to Missy Elliott, who was not rapping about plant chemistry.

Sources & Further Reading:

Siegmund, B., Leitner, E., Pfannhauser, W. (1999).  Determination of the Nicotine Content of Various Edible Nightshades (Solanaceae) and Their Products and Estimation of the Associated Dietary Nicotine Intake.  J. Agric. Food Chem. 47: 3113-3120.

Steppuhn, A., Baldwin, I.T. (2007).  Resistance management in a native plant: nicotine prevents herbivores from compensating for plant protease inhibitors.  Ecology Letters 10: 499-511.

Sullivan, R.J., Hagen, E.H., Hammerstein, P. (2008).  Revealing the paradox of drug reward in human evolution.  Proc. R. Soc. B 275: 1231-1241.

Tetenyi, P. (1987).  A chemotaxonomic classification of the Solanaceae.  Annals of the Missouri Botanical Garden 74.3: 600-608.  [This is the paper that the confusing diagram was from– chemotaxonomy is almost never used by botanists or plant biologists nowadays.]