07 Aug 2014 What’s up with scientific research into the hangover?

What are you presenting at the conference? [Held by the Alcohol Hangover Research Group in Seattle, June 2014]
We’ve got a quite good research grant from the EU for a two-year project on alcohol hangover, particularly looking at the cognitive effects of hangover. In other words, if you have a hangover, does your memory function normally?

And also looking at the link between alcohol hangover and alcohol use disorder. I’m going to be presenting some of the preliminary data from the study on that latter question about hangover and alcohol use disorder.

The interest there is that everyone tends to think that hangover is a good thing because it stops you from drinking too much, it’s like the natural brake on drinking. And we all drink too much and that’s a big problem, so anything that stops people from drinking too much is a good thing. That’s the kind of folk knowledge.
And yet, a number of studies have actually shown the opposite. If hangover is a natural brake on drinking, then alcoholics should get the least hangovers of anyone—that the reason they are alcoholic is that they don’t have that natural brake on drinking.

But actually a number of studies in the US have actually shown the opposite, that alcoholics get the most severe hangovers, even when you control for the amount of alcohol consumed. And so it seems like it’s a more complex relationship between being at risk of alcoholism and hangovers.

Do we know what causes hangovers?

Not completely, but there’s definitely some fairly good evidence. One component is the way that alcohol is metabolised.

When you drink alcohol, there’s an enzyme in the body that breaks down the ethanol in alcohol into metabolites—after you’ve had a drink of alcohol and felt drunk, once you start to feel sober again, that’s because your body has metabolised the ethanol.

But once the ethanol has been metabolised, there are usually other alcohols in smaller quantities in alcoholic beverages. One such compound is methanol, and when the body metabolises methanol, it metabolises it into toxins—formaldehyde and formic acid. And those make you feel ill, sort of poison you a little bit.

So one part of a hangover is the production of formaldehyde and formic acid, which comes online about 10 or so hours after you’ve been drinking. And the interesting thing about that is that the enzymes in your body that break down alcohols would prefer to break down ethanol first and methanol second. And it means that when you’re in a hangover phase, if you drink more alcohol you’ll actually stop your body from breaking down methanol and the things that are making you feel ill, and instead go back to working on the ethanol and leave the methanol intact.

So there is a biological basis for the hair of the dog. And that’s one of the possible risk factors for why hangover might be a risk factor for alcoholism rather than a natural block for it.

But that’s not the only mechanism, there are other mechanisms as well. Another mechanism for hangover is immunosuppression. So you know that puffy feeling you get after a night of drinking—that’s due to an immune response.

How long have you been studying hangovers?
Probably about 10 years.

How has the science of hangovers changed since you first began working on this subject?

There are more people working on it now. When I started working on it, there were only a handful of papers. There was a lot of stuff in the 70s, and then it all petered out, and then it resurged in the late 90s and early 2000s.

How it’s changed is that knowledge has advanced—when we started off, the cognitive effects were clear. We did a big review in 2008 of all the cognitive effects studies of hangover that existed and concluded from that that there was some evidence of long-term memory and attention deficits. But it was very muddy. Say there were six or seven studies that had looked at attention, five or so showed something and the other two didn’t. Science is never as clear cut as you think it’s going to be. But since then, there have been more studies done and there is now a clearer picture of attention and memory being affected. And one thing we’re trying to do in our study is to look in a bit more detail at what particular aspects of attention and memory are affected.

Another development is there’s a psychological function known as executive function—that’s our ability to think laterally and plan. It’s almost like the mind taking control of itself and saying “okay, where are we, what do we want to do next,” and deliberately planning actions known as executive functions. And that’s been very largely neglected in hangover research, even though there’s evidence that alcohol use affects executive function. So one thing we’re doing that is novel is to look in quite a lot of detail at hangover affects executive functioning.

Do you think we will ever find a cure for hangovers?
There is research looking at hangover cures. A few things were tried and found to heal hangover symptoms—one of them was anti-inflammatory drugs that you might take when you have a headache, and that ties in with the idea of hangover being an inflammatory response due to immunosuppression. But then again, given that headache is one of the top symptoms of hangover it’s not very surprising that headache pills will reduce hangover symptoms.
There are a few other things that have been tried—one was [migraine drug] Tolfenamic acid, which was found to show benefits, and the herb borage was found to ease hangover symptoms. At the current moment there have been a number of studies looking at different treatments. You need replication to have more confidence that they actually are effective.
What about people who claim to have folk cures for hangover, like burnt toast or pickle juice? Do you believe them?
Not usually. But the interesting thing is that one of the most effective hangover cures are ones that administer glucose. One of the other mechanisms of the hangover is to do with glucose metabolism and not having enough blood sugar. In Britain one of the most prevalent hangover cures is a big fried breakfast—fried eggs, sausages, baked beans, and all the rest—that’s well-renowned as a hangover cure in Britain, and it probably does work because there are lot of carbohydrates in that meal. And that will restore depleted sugar levels….

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