These pink elephants are caused by what part of the absinthe, exactly?

Back in 2002 I went to Prague, where I was able to legally sample that storied vice of brooding 19th-century artists, absinthe.  The preferred method of preparation was to pour some of the liquor into a large spoon, add a pinch of sugar, and heat it over a candle flame until the sugar dissolved.  It was a ritual that added to the sense of participating in a dangerous, clandestine tradition, and coupled with the pre-Industrial-era architecture and cobblestone streets, I would leave the pub fully expecting to run into a Van Gogh-like figure, or at least hallucinate one.

"The absinthe drinker" being visited by the green fairy. By Czech painter Viktor Oliva, 1901.

Somewhat disappointingly, I never hallucinated any depressive one-eared artists.  Or anything else for that matter.  In fact, despite the 120-proof alcohol content, I only got modestly tipsy, thanks to the absinthe’s bitter, anise-y flavor (the origin for the word “absinthe” is likely the Greek apsinthion, which means “undrinkable”).  The one time I followed the absinthe up with a couple glasses of red wine, I did end up with a headache that might have inspired some gruesomely morbid poetry, but I wasn’t feeling moved by a creative impulse so much as by the impulse to find out what had happened to my Advil over the course of 3 flights and two layovers.

Fast forward to this past St. Patrick’s Day, when my friends brought over a bottle of appropriately green absinthe made and sold just a few miles away at our local distillery, St. George’s.  While the mystique was not so pronounced in my living room as it had been in a Czech pub, the product was definitely the same: the bottle confidently proclaimed that it contained extracts from wormwood (Artemisia absinthium, the plant that gives absinthe its distinctive flavor and color).  Ten years ago, I had to go to Europe for this stuff.  Why is it legal here now?

St. George's absinthe in my kitchen.

The ill-defined ills of alcohol vs. absinthe

The legal ambiguity of absinthe has gone through several iterations, which are summarized nicely in this 2006 article, just before absinthe became legal in the US in 2007.  For much of the 20th century, absinthe was illegal in most of Europe, as well as the US, mostly because it was such a conveniently evil-looking scapegoat for all the ills of alcohol.  At the end of the 1800s, absinthe was hugely popular in France (among other countries), and hugely potent (the high-end stuff was 60-68% alcohol).

What’s hard to imagine is that in the late 1800s and early 1900s, alcoholism wasn’t really characterized as its own disease, and the criteria for scientific rigor that we take for granted in peer-reviewed publications these days hadn’t been established yet.  Anecdotal evidence and unblinded, single-patient experimentation and observation were solid science back then.  Ergo, a bunch of policy makers and doctors observed a whole sector of the populace passing out, hallucinating, and getting morose and unproductive while their livers fell apart.  Those same folks were drinking daily pintfuls of absinthe, and so the symptoms got chalked up to absinthe rather than alcohol generally.  This worked out great for the budding temperance movement, which found banning absinthe to be an easier battle to win than banning beer and wine.  Absinthe was banned in Belgium in 1905, Switzerland in 1908, the US in 1912, Italy in 1913, France in 1915, and Germany in 1923.

"Alcohol the enemy" poster for display in schools. By Frederic Christol, 1910.

Those pink elephants are probably from the methanol. Or maybe the antimony.

Ok, but hold on.  Was it all really some sort of placebo effect?  Was “absinthism” really no more than alcoholism, coupled with peaks of actuate intoxication?  Didn’t the green fairy have any magic powers at all?

Here is where things get a little more murky, because we no longer have physical samples of all the absinthe people drank 100 years ago.  What we do know is that the content of absinthe wasn’t very carefully regulated, and that it was adulterated in all kinds of ways.  Poor distillation practices led to methanol in cheap versions, and an emphasis on a nice bright green color led to the addition of all kinds of chemicals to heighten its intensity (high-quality absinthe owes its color to post-distillation addition of wormwood extract, which is bright green because of chlorophyll, and dims to yellowy-green after prolonged exposure to light).  These copper and antimony compounds added to create an emerald-green color could have caused many toxic effects.

Anything this color was not made by a plant. These days, it's probably FD and C green #3, but in the early 1900s, it might have been a toxic copper compound. Picture from http://www.absinthesupply.com

What about wormwood? It certainly sounds sinister…

And then, at last, there’s wormwood itself.  Wormwood (so called because it’s been used forever as an antihelmintic, or de-wormer) is the bitter flavor in absinthe, and is used twice in the preparation of absinthe; first in the initial distillation of herbal extracts, and then later to add color and flavor.  In the early 1900s, a handful of experiments demonstrated that wormwood oil is potently toxic, and not at all like alcohol.  It’s a convulsant, and when injected directly into the stomachs of animals, it produced seizures and rapid death.  But scientists at the time weren’t careful about distinguishing between wormwood oil, wormwood essence, alcoholic wormwood extract, and absinthe, so the effects of straight wormwood oil were overgeneralized to absinthe.

Wormwood: Artemisia absinthium. Painting by W. Muller, 1885.

In the mid 1900s, the chemical responsible for wormwood’s toxic effect was identified: thujone.  Thujone is neurotoxic–it causes seizures by inhibiting GABA receptors in neurons.  At lower doses, it also causes anxiety and twitchiness. It’s also damaging to the liver, causing symptoms of porphyria (that vampire-ish disease where the “heme” in hemoglobin doesn’t get made properly), that would be exacerbated by alcohol.

- Alpha thujone, the neurotoxic component of wormwood. It has probably been given credit for a lot more of "absinthism's" symptoms than it deserves.

Armed with what seemed to be a reasonable molecular candidate for absinthe’s ill effects, Europe revisited its ban on absinthe in 1988, and instead directed its regulation to thujone.  Some estimates of the pre-ban era thujone content of absinthe were as high as 260 mg/L, which would have been enough to cause porphyria, anxiety, and maybe even seizures (for intraperitoneal delivery, thujone is lethal in 50% of rats at 45mg/kg of body weight).  These estimates were probably hugely inflated, because they assumed almost every single thujone molecule in the initial wormwood would have made it into the final absinthe product.     After mulling it over a bit, most of Europe decided that absinthe was fine so long as the thujone content was below 35mg/L, far below the level needed to cause those symptoms.

Summary of thujone toxicity. From Padosch et al., 2006, Table 3.

Of course, a sector of the populace now focused on thujone as what must be the really good, potent stuff in absinthe, and a black market for enhanced-thujone absinthe and for wormwood oil emerged (in 1997 one guy even confused wormwood oil he bought online with absinthe, and nearly killed himself with it).  But the thing is, even though thujone is certainly toxic, it’s not any fun: it doesn’t cause hallucinations or euphoria, just seizures and liver toxicity.  It’s a bit like people noticing that lead poisoning makes you crazy and  saying “buy our white paint!  Now with increased lead!”

Eventually, the US followed suit, and amended their rule on absinthe to say that it must be “thujone-free” where thujone-free means “less thujone than 10mg/L.” It’s a fairly arbitrary cutoff, but certainly enough to avoid any toxic effects from thujone directly.

Which brings us back to the legal, US-made bottle of absinthe on my shelf, which is pretty high-grade stuff.    It’s color is mossy green, due strictly to chlorophyll, and like other high-grade absinthe, it contains a high proportion of ethanol-soluble herbal extracts that precipitate when you add water (ice).  It even tastes pretty good.  But at the end of the day, it’s intoxicating because it’s 60% alcohol.  Something to be savored in tiny sips, and certainly able to bring about a whole range of perception-altering effects, but no more so than Bacardi 151.

Our local bottle of absinthe starts out clear, but precipitates to a cloudy yellow when you add ice, due to water-insoluble herbal extracts.

If you want to learn more, check out the 2006 paper.  It’s a great read.  The 2000 paper is also handy for neurobiology details.

Padosch SA, Lachenmeier DW, & Kröner LU (2006). Absinthism: a fictitious 19th century syndrome with present impact. Substance abuse treatment, prevention, and policy, 1 PMID: 16722551
Höld KM, Sirisoma NS, Ikeda T, Narahashi T, & Casida JE (2000). Alpha-thujone (the active component of absinthe): gamma-aminobutyric acid type A receptor modulation and metabolic detoxification. Proceedings of the National Academy of Sciences of the United States of America, 97 (8), 3826-31 PMID: 10725394
ResearchBlogging.org

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3 thoughts on “These pink elephants are caused by what part of the absinthe, exactly?

  1. Cool article but we DO have physical samples left from 100 years ago. We have also tested them and as it turns out around 40% would pass the current US regulation of 10ppm. http://www.thujone.info is where you can find that study and tons more on pre-ban absinthe. You’ll notice not a single one comes close to that old estimate of 260ppm, or any of the other theories the scientists working with the temperance movement came up with.

    If you are looking to buy and taste pre-ban… I hope you have lots of money but you can get some here: http://www.oxygenee.com/vintage.html There are other vendors but you may have to find them yourself.

    Believe me, the vintage stuff is wonderful after resting in a bottle for decades or a century.

    Sante!

    • Well, that’s kind of fantastic. Although I’ll have to put my starving postdoc days behind me before I can afford to try it out. Those thujone estimates seem consistent with what I was reading; some of the present-day recapitulations of pre-ban era recipes were coming up with thujone content in the 5-30 mg/L range, so that seems a lot more realistic than 260 (and legal, sweet!). It seems crazy to me that the 260 mark gained so much credibility and was so heavily cited when any organic chemist could tell you that you never realize 100% yield on an extraction from biological material.

  2. Pingback: Toxic and toothsome: a tale of two wild Asteraceae | A bouquet from Mendel

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