Why Does Mixing Alcohol Cause Hangovers?

There’s a widespread notion that mixing alcoholic drinks causes the worst hangovers. For instance, starting with wine, then switching to beer could be worse than sticking to wine for the whole evening. But is there scientific evidence that mixing alcohol can get people drunk faster, or for that matter, cause worse hangovers?

Anyone who ever drinks too much knows the consequences of alcohol consumption: splitting headaches, sickness, dizziness, dehydration, nausea and vomiting. A hangover happens to almost everyone1 In fact, according to the Centers for Disease Control and Prevention2, one in six adults in the US over-drinks about four times a month.

But before learning about the impact of mixing alcohol and the severity of hangovers, first, you have to understand what specifically causes a hangover. A review of previous research published in 2000 confirms that the causes of the main symptoms of hangovers are dehydration, ingestion of congeners (a group of substances that give flavor to some drinks), and the toxic effects of alcohol itself3. Also, there’s evidence that the immune system is disrupted and that this could be the cause of the headache, nausea, and fatigue4.

So, you ask, is there scientific evidence that mixing different types of alcohol makes you feel unwell during your drinking session and contribute to a worse hangover?

As of now, no scientist seems to have done specific research where people are randomly assigned to drink beer followed by wine or wine followed by beer. In other words, there is no scientific evidence, but there are some likely culprits.

1.CONGENERS

Beyond the ethanol that triggers intoxication, the other key ingredients that affect hangovers are what the beverage industry calls congeners. But what are congeners, you ask?

They’re byproducts like methanol, acetone, acetaldehyde, fusel oil, and tannins, which give darker drinks their color and part of their flavor. These congeners are formed when grains are fermented and then aged to create alcohol like tequila, whiskey, and rum.

Liquors with high amounts of congeners, like cognac, tequila, and whiskey — especially Bourbon — have been shown to cause more intense hangovers5. Clear drinks like vodka, gin, and rum, however, contain lower levels of congeners6 and may cut down your chances of feeling crummy. Bourbon whiskey, for example, contains 37 times the quantity of congeners as vodka.

Perhaps those who mix alcohol are more likely to choose a dark-colored drink containing higher levels of these substances simply by virtue of their wider drinking range, but again it isn't the mixing in itself that causes the problem

It’s important to state that no matter which drink you choose, the amount you drink has the biggest effect on hangovers.

2. ORDER OF DRINKS

There is a theory that says that it's not the mixing that matters when you drink alcohol; it's the order that matters.

According to Dr. Kevin Strang7, if you start drinking something with lower alcohol content, your body gets used to getting drunk at a certain rate. When you switch to something with higher alcohol content, your body still thinks it's getting drunk at the rate of the first drink, so you drink faster… and subsequently, you get sicker.

The good news is that if you start with a drink that has a high alcohol content, and switch to something with lower alcohol content (like going from whiskey to beer), you probably will suffer less. That’s where the famous saying “Beer before liquor, never been sicker; liquor before beer, you're in the clear.”

Although this sounds like a reasonable theory, the problem is there is no scientific evidence to prove it. For now, it is important to keep in mind that any excessive amount of alcohol is going to lead to an awful hangover.

3. IT’S THE ALCOHOL, STUPID

Ultimately, experiencing a hangover and feeling sick while intoxicated is due to the amount of alcohol consumed and the time period it's consumed over. The higher the alcohol content of a drink, and the faster you drink it, the worse the hangover.

A healthy adult body is only able to eliminate one standard drink (or 10 grams of alcohol) per hour. At this pace of alcohol consumption, the likelihood of experiencing a hangover is very slim.

As mentioned earlier, no scientist seems to have done the study of people randomly assigned to drink beer followed by liquor or liquor followed by beer. So perhaps it’s not the mix of alcohol that matters, but the effect that the strength of those drinks has on judgment.

Beer is only about half the strength of wine, so starting on, it leads to less intoxication if followed by the stronger stuff. But if a person starts on wine or spirits, then their judgment may be impaired enough to drink more heavily later. There's certainly evidence8 that people are not good at judging their own drunkenness. At low levels, people overestimate the amount of alcohol in our blood, but after a few drinks, they start to underestimate it.

TAKE AWAY

Mixing drinks might not be a good idea as it reduces the likelihood you're able to keep track of how many standard drinks you've consumed. It could also increase the rate of alcohol you consume if you move from a beverage with a low alcohol content to one with higher alcohol content.

A few tips to keep in mind when you drink alcohol to make your hangover more manageable:

EAT BEFORE YOU DRINK

Delaying the absorption of alcohol is a good first step toward avoiding a hangover.

In other words, the key here is to eat before you drink—before any alcohol has been absorbed into your bloodstream. Eating before drinking alcohol allows the alcohol to be assimilated more slowly into your system and the effects of alcohol won’t happen as quickly.

AVOID LIQUOR HIGH IN CONGENERS

Liquors with high amounts of congeners, like cognac, tequila, and whiskey — especially Bourbon — have been shown to cause more intense hangovers9. Clear drinks like vodka, gin, and rum, however, contain lower levels of congeners10 and may cut down your chances of feeling crummy.

SKIP THE CHAMPAGNE

It turns out that sparkling drinks and mixers can actually make your hangover worse. Researchers found the gas bubbles in carbonated beverages cause the stomach to expand and increase the rate of alcohol absorption in the blood11.

SPACE OUT YOUR DRINKS (AND HYDRATE IN BETWEEN)

The only surefire way to avoid a hangover is to not drink at all. Plan B? Drink in moderation and pace yourself.