The fact that dwarves can hold their alcohol better than humans tells us a tremendous amount about their biology.

The fact that dwarves can hold their alcohol better than humans tells us a tremendous amount about their biology.

The hard-drinking dwarf is a common trope in fantasy. It's a trope that by and large holds true across literature; whether you're reading Pathfinder, Warhammer or Discworld, the dwarven passion for beer and spirits remains constant even as almost everything else changes. Much of the blame for this can be put on Tolkien, who was, of course, an immense influence on modern fantasy as a whole, although it must be noted that the dwarves in The Hobbit and The Lord of the Rings don't actually seem to drink that much more than anybody else. Most of the rest of the blame can be attributed to the fact that many of the elements that Gygax and people like him incorporated into their dwarves came from Norse and Slavic myth, where heavy alcohol use was a cultural imperative. While much has been said about what cultural factors underlie dwarven alcohol use, not as much has been said about what biological differences allow them to drink the way that they do. Dwarves, as we sometimes forget, are meant to be a very different race from humans, and not merely "short, tough people." If anything, dwarves are probably even more biologically different from humans than elves are, since it's very rare that you see a campaign setting or fantasy world with half-dwarves. Scientists actually know quite a lot about the biological factors that distinguish different groups of humans' ability to handle alcohol, so we can take some of this knowledge and infer some of the ways that dwarven physiology might differ from humans.

To understand these differences, you have to know one basic fact: when alcohol (or more properly, ethanol) enters the body, it gets broken down in a two-step process, which produces chemicals called acetaldehyde and acetic acid. Once you know this one fact, you then obviously need to know several hundred other facts to really appreciate the whole picture, but we're going to try to keep things simple. Step one: ethanol gets metabolized by an enzyme called alcohol dehydrogenase to acetaldehyde, which is the chemical which causes most of the bad parts of drinking. Acetaldehyde is both a carcinogen and a poison in large doses, and when it builds up, people become very, very sick, with facial flushing, light-headedness, chest palpitations, nausea and vomiting, and basically all the symptoms you'd expect of a hangover or of having had one too many beers. Under ordinary circumstances, acetaldehyde is in turn metabolized by an enzyme called aldehyde dehydrogenase, producing acetic acid. Acetic acid may sound scary, but it's actually a common part of your diet, because it's the active ingredient in regular white vinegar. Although it'll sting if you pour it on a cut, the amount produced in the human body during the metabolism of booze is basically harmless.

Now here's the neat part: different people have different levels of aldehyde dehydrogenase and alcohol dehydrogenase, and this seems to directly predict how well they hold their alcohol. Levels of these two enzymes can differ significantly between two members of the same family and can differ hugely between two different ethnic groups. For example, a large body of research has shown that a number of Asian populations have naturally lower levels of aldehyde dehydrogenase, which means that as a population, they're slower to clean aldehyde out of their system. As a result, they feel sicker on lower doses of alcohol than a European of a similar size. Similarly, genes for less efficient forms of alcohol dehydrogenase seem to be more frequently seen in Jews  than in non-Jews, and this is thought to be why, on average, they tolerate alcohol less well than people of other genetic backgrounds. Such things aren't divided solely on ethnic lines, though. On average, women have less alcohol dehydrogenase in their gut than men, which means they're more likely to experience the unpleasant physical effects of drinking, and at a low dose. In essence, if one or both of the enzymes are less efficient in your body, then when you drink, you get more of the unpleasant effects and less of the pleasant effects. The up-side of this is that people who don't enjoy alcohol seem to be at much lower risk of alcoholism. The down side is that they don't have as much fun at parties. Of course, someone who's really dedicated to drinking can build up a tolerance to alcohol and, low enzymes or not, become as hard a drinker as anyone else, but it takes more dedication.

What can we say about dwarves, then? It seems probable that dwarves, as a race, have either higher levels of these two enzymes, or else more efficient versions of them. This has implication far beyond the cultural and dietary role of alcohol, though. Aldehyde and alcohol dehydrogenase play vital roles in removing other toxins from the body too, and they have effects on the body's energy generation and metabolism systems in ways that we don't fully understand. Hyperfunctional dehydrogenases and other related enzymes  could confer some of the other dwarven traits, such as their enhanced constitutions and resistances to other poisons.

Whether or not this also explains why so many people feel that dwarves ought to have Scottish accents is an intellectual exercise that I leave to the reader. 

More than four years ago, Dr. Eris Lis, M.D., began writing a series of brilliant and informative posts on RPGs through the eyes of a medical professional, and this is the one that appeared here on September 14, 2014. Lis is a physician, gamer, and author of the Skirmisher Publishing LLC OGL sourcebook Insults & Injuries, which is also available for the Pathfinder RPG system.