Bourbon, vodka and hangovers

I went to medical school in the days when controls on human experimentation were not very robust (I understate). I think about that around Christmas time because one of the ways this penurious medical student used to make a few bucks was by volunteering for medical experiments (and eating Spaghetti-Os at 19 cents a can). One year I desperately wanted to buy my girlfriend an expensive ($20) book (Larousse Gastronomique; last time I mentioned it here she told me -- via email since she lives across the ocean -- she still has it after more than 40 years; hug and a wave from me and Mrs. R.). I made the cash all at once by letting some researcher pump me intravenously with ethyl alcohol while simultaneously measuring my retinal response via a contact lens with electrodes on it. Did I become inebriated? What do you think. Fortunately I lived directly across the street from the medical center in a student dormitory. Do you think they made sure I got there safely? What do you think. Did I have a hangover? What do you think.

Now, 42 years later, I find out it could have been worse. They could have given me intravenous bourbon:

Many alcoholic beverages contain byproducts of the materials used in the fermenting process. These byproducts are called "congeners," complex organic molecules with toxic effects including acetone, acetaldehyde, fusel oil, tannins, and furfural. Bourbon has 37 times the amount of congeners that vodka has. A new study has found that while drinking a lot of bourbon can cause a worse hangover than drinking a lot of vodka, impairment in people's next-day task performance is about the same for both beverages. (via EurekAlert)

A new paper by researchers at Brown and Boston Universities and the University of Michigan (big party schools, right?) sounds interesting but it's subscription only and despite my flirtation with intravenous booze I'm not much of a drinker and don't read this journal for personal or professional reasons. A half bottle of wine at dinner is likely to make me fall forward with my face in the plate. Still, I find the hangover issue intellectually interesting (since I'm not at risk for getting them) and the abstract and press release are freely available. Here's the set-up:

Background: This study assessed the effects of heavy drinking with high or low congener beverages on next-day neurocognitive performance, and the extent to which these effects were mediated by alcohol-related sleep disturbance or alcoholic beverage congeners, and correlated with the intensity of hangover.

Methods: Healthy heavy drinkers age 21 to 33 (n = 95) participated in 2 drinking nights after an acclimatization night. They drank to a mean of 0.11 g% breath alcohol concentration on vodka or bourbon one night with matched placebo the other night, randomized for type and order. Polysomnography recordings were made overnight; self-report and neurocognitive measures were assessed the next morning.

(Rohsenow et al., "Intoxication With Bourbon Versus Vodka: Effects on Hangover, Sleep, and Next-Day Neurocognitive Performance in Young Adults," abstract).

Wow. This puts my little foray into i.v., alcohol to shame. I hope the Cochrane Collaborative has taken notice this is a randomized controlled trial, so now we have incontrovertible evidence about bourbon and vodka. Next stop the British Medical Journal. But back to the study.

Some of those little "congeners" are nasty things, but the authors note that there's not enough of them to be poisonous in the usual alcoholic beverage. Because, c'mon, who would call a severe headache, nausea, inability to think clearly and feeling really shitty a toxic effect? As an environmental epidemiologist, I certainly wouldn't consider a consumer product or food or air or water pollutant that did all those things with great predictability toxic. Would you?

Moving on. They're not poisonous, but there are a lot more of the non poisonous things in darker distilled beverages and wines than the lighter colored ones. (Mental note: dark, bad; light, good.) The main contribution of this study seems to be the effect on safety:

"We wanted to investigate next-day effects of bourbon versus vodka while ensuring that BALs [blood alcohol levels] were zero or almost zero when we studied performance, and we used a variety of performance measures classified by their relevance to safety," said Rohsenow. "We wanted to use a new hangover questionnaire that included only the symptoms that had been found to be valid in laboratory studies of hangover. We wanted to find out if bourbon's effects the next day were due to different effects on sleep, so people's sleep patterns were recorded while they slept. Finally, we wanted to know if performance impairments the morning after drinking were associated with how hung-over the person felt."

Here are some results. The more alcohol, the more hungover subjects felt (placebo comparison; that must been a tough one for the subjects to figure out), and bourbon was worse than vodka. Alcohol alone was sufficient make people do worse on performance requiring paying attention while simulataneously trying to make rapid and accurate choices on a test. Performance-wise, bourbon wasn't any worse than vodka. These tests were done with zero or near-zero blood alcohol the next day and the subjects didn't recognize that their performance was degraded. The authors say this result is consistent with studies of pilots whose performance is measured the morning after a night of drinking. As a traveler, I'm very comforted to know that. I always appreciate consistency in scientific results.

I tend to sleep really badly after drinking even a little close to bed time and this study confirmed that people who drank the booze woke up more during the night. But again, bourbon wasn't worse than vodka. It's the alcohol. So the bourbon hangover effect doesn't appear to be from any effect on sleep.

So far everything seems to fit together. But I was puzzled by this finding:

Fourth, people who reported more hangover symptoms also did worse in their ability to pay attention for a continuous period of time while making rapid accurate choices."

Regarding this last finding, that people with more hangover symptoms - feelings of headache, nausea, general lousiness, thirst and fatigue - also performed worse when required to pay continuous attention and make choices, Rohsenow said that feeling worse was perhaps distracting them, or that it just hurt more to use the extra energy needed to pay close attention. "A second possibility is that as alcohol was metabolized into other substances in the body before leaving, these substances had a direct effect on the nervous system in addition to increasing hangover so that these were two separate but related after-effects of drinking to intoxication," she said.

So bourbon gives you a worse hangover and a worse hangover affects performance but performance isn't affected by whether it's bourbon or vodka. Something seems discordant here. Despite that, the bottom line seems fairly clear:

The bottom line, said Rohsenow, is that becoming intoxicated to a .11 g% BAL makes it less safe for a person to engage in behaviors required for safety-sensitive performance the next morning. "Many safety-sensitive occupations require that workers be able to pay close attention to a number of tasks over a period of time, and to respond quickly with the right choices, and drinking to excess was found to impair this performance just after alcohol had left people's bodies."

This is the public health bottom line. It doesn't matter if it's bourbon or vodka or the wine punch or the Christmas Party eggnog. It's the alcohol. And it's a Big Deal.