Men's Guide to Women

The idea that what you drink dictates your mood is firmly implanted in most drinkers' minds. And there is a ready explanation to hand: different brews have different strengths and their own characteristic mix of trace compounds, and it seems only reasonable that these factors could affect how you feel. But some scientists think we are fooling ourselves: we might as well be drinking pure ethanol diluted with water.

To understand how particular drinks might pack different kinds of punch, it helps to know how the body processes alcohol—or ethanol, to be precise. After you take a drink, the liquid's first stop is in the stomach. As it sloshes around, some alcohol gets broken down and a small amount passes through the stomach wall and into the bloodstream. Then a ring-shaped muscle called the pyloric valve opens up at the bottom of the stomach and your drink drops into the small intestine, which has a much greater surface area than the stomach and so allows alcohol to be absorbed far more rapidly.

At this point you're beginning to feel pretty fine as the alcohol work its magic on your brain. But your liver is already chugging along trying to rid your blood of the poisonous alcohol that's pouring in through the intestinal wall. The liver processes about 15 millilitres of ethanol per hour, roughly the amount in a small glass of wine. How drunk you eventually feel depends on a race between absorption and breakdown: if absorption were instant, you'd feel the full effect of each drink, but in practice the liver will already have cleared some alcohol from your body by the time it is all absorbed.

Some nutrients, including fructose, can speed up the breakdown of alcohol in the liver (Alcohol and Alcoholism, vol 26, p 53). But experts scoff at the idea that adding cranberry juice to your vodka, for example, makes for a gentler buzz. "You'd have to eat enormous amounts of fructose. It'd give you a stomachache," says Wayne Jones of the National Laboratory of Forensic Toxicology in Linköping, Sweden.

The liver clears alcohol at a nearly constant rate, so how intoxicated you become depends mostly on how fast the alcohol is absorbed. If the stomach retains alcohol for a long time, its concentration in the blood will rise relatively slowly. But if your drink passes straight through into the small intestine, blood alcohol levels rise rapidly, leading to a correspondingly sudden and powerful intoxication.

Sugars and fats tend to keep the pyloric valve closed longer while the stomach digests them. So drinks that are creamy or sugary will creep up on you more slowly—hence the time-honoured idea that a glass of milk will line your stomach. "People don't drink milk and alcohol to get high," observes Robert Swift, a psychiatrist and pharmacologist at Brown University in Providence, Rhode Island. A high-fat meal consumed with a bottle of wine will keep the pyloric valve shut for hours while the stomach digests the food.

The strength of a drink can also influence how alcohol gets absorbed, but in rather complicated ways. Generally speaking, weaker drinks are absorbed more slowly. Yet downing a shot of whisky on an empty stomach won't necessarily give you a quick high. In some people, strong drinks irritate the pyloric valve, so it clamps shut and keeps the alcohol in the stomach where absorption is slower.

The effects of alcoholic strength get even more complicated when food is involved. In 1993, Charles Lieber and his colleagues at Bronx Veterans Affairs Medical Center, New York, compared the effects of drinking whisky and beer ( Alcoholism—Clinical and Experimental Research, vol 17, p 709). In men with empty stomachs, whisky raised blood-alcohol levels more quickly than beer. But strangely, the effect was reversed in the men who had eaten first. Because food keeps alcohol in the stomach longer, Lieber thinks this could be explained if the alcohol-metabolising enzyme in the stomach works more effectively on concentrated alcohol.

The bottom line is that "absorption is really, really unpredictable", says Jones. "You never really know how the stomach is going to react." With so many variables involved, any attempt to control the quality of your alcohol buzz by picking a drink with certain absorption characteristics looks futile.

But of course, ethanol isn't the only substance entering the bloodstream. Fermenters and distillers use a huge range of techniques and ingredients to make alcoholic drinks, creating a corresponding variety of chemicals. Some only affect taste and appearance; others could, in principle, change the type of intoxication that you experience.

For example, most drinks also contain traces of alcohols other than ethanol. "Each has an intoxicating effect, a slightly different one, actually," says Sean O'Connor, an alcohol metabolism expert at Indiana University. He notes that the neural toxicities are different, indicating that the alcohols have different effects on the brain.

The most common alternative alcohol is methanol, the wood alcohol found in antifreeze and paint thinners. But it is also dangerous. People have gone blind or died from drinking methanol, either knowingly or in illicit liquor made cheaply by substituting this alcohol for ethanol.

Even some fruit-based alcoholic drinks such as red wine or plum brandy can contain up to 2 per cent methanol. But Jones thinks you won't notice any difference in the kind of drunkenness produced by these drinks—any additional intoxication from methanol is likely to be masked by the larger quantities of ethanol. You might wake up the next morning feeling awful, though. The liver breaks down methanol into toxic compounds that Jones believes are responsible for the worst hangover symptoms (see "Desperate remedies"). To avoid this, you could try drinking a purer drink such as vodka, which contains virtually no methanol.

As well as a range of alcohols, drinks normally contain myriad substances of various types and origins—including spices and herbs that may have been part of the brew. "Particularly in brandies and whiskies, there are all sorts of strange compounds, the effects of which aren't really known," says Swift. [i]

[i] Boyce, Nell; Thomas, Celia (November 27, 1999). What’s your poison? [online] Available: http://www.newscientist.com/channel/being-human/drugs-alcohol/mg16422145.600 [accesses 31 December 2007]