In the past scientists attributed this susceptibility to women's smaller body size and their relatively higher percentage of fatty tissue. For this study, however, the researchers focused on what is known as first-pass metabolism. Before alcohol reaches the blood stream, it goes through the stomach, where so-called gastric alcohol dehydrogenase (ADH) isozymes break some of it down. "In an earlier study we found that women have less of this ADH activity than men do," notes lead author Charles Lieber of the Mount Sinai School of Medicine. "Accordingly, women have a lesser first-pass metabolism and, therefore, for a given dose of alcohol, their blood level is higher than it is for men."
Following up on that research, the team recently turned their attention to the makeup of ADH. They found that one of the enzyme's three components, glutathione-dependent fomaldehyde dehydrogenase (x-ADH), is deficient in women, thus explaining their lower ADH activity levels. To Schenker, the take-home message is clear: "Women simply need to be more cautious than males in terms of the amount of drinking they do."