Say you’re a woman challenged to a drinking contest by a male companion. Do you advocate for a handicap based on your double X chromosomes, or do you saddle up to the bar and go drink for drink, believing in equality of the sexes in all matters?
The Straight Talk
Determining whether the man has a physiologic upper hand depends on how ethanol is absorbed, distributed, and excreted from the body, and how this differs (if at all) between the two sexes.
Anecdotally, most people recognize that, given the same amount of alcohol, large people will feel its affects less than small people will. This is simply due to the fact that after ethanol is absorbed from the gastrointestinal tract into the bloodstream, it’s distributed throughout the body; the larger the volume of distribution, the less concentrated the substance. Since, on average, women are smaller than men, it stands to reason that size alone would give women a disadvantage. But even after adjusting for weight and height, the average woman will still get drunker faster than the average man. The answer lies not in size per se, but rather, what we’re made of.
Though there are always exceptions, on average, a man’s body will have more muscle and less fat than a woman’s. Since muscle tissue contains more water than fat tissue, a man’s body contains a greater percentage of water than a woman’s, around 60 percent compared to 50 percent. Alcohol dissolves in water and not in fat, so as the ethanol moves from the stomach into the blood, it will be distributed in a greater number of a man’s cells than a woman’s. Consequently, ethanol is more concentrated in a woman’s bloodstream; she will have a higher Blood Alcohol Content (BAC) with the same amount of drinks. Higher BAC leads to more ethanol going to the organs, where it exerts its intoxicating effects.
But what if the woman is more muscular than the man, and they weigh approximately the same? She may also be hindered by her rate of beer breakdown. While the majority of ethanol is oxidized in the liver, a small amount is metabolized in the stomach, by an enzyme called gastric alcohol dehydrogenase. A few small studies have shown that in younger women, the activity of this enzyme is significantly lower compared with their male counterparts. This means men are able to break down more ethanol in the stomach, so less is absorbed into the bloodstream.
