9 January 2006
Hormones The Key In Alcohol’s Effects On Women
Researchers say that while women consume less alcohol than men, they are more susceptible to some of the negative effects of alcohol use, such as cirrhosis of the liver, cardiac disease, and neurological impairments. The study, in Alcoholism: Clinical & Experimental Research, found that female rats are not only less sensitive to the sedating effects of alcohol, but that cycling hormonal levels can mediate alcohol's effects.
"Despite the fact that men outnumber women in terms of having alcohol-related problems, women are more vulnerable to many of the effects of alcohol use," said the study's first author, Duke University researcher Young May Cha. Cha and her colleagues decided to study what effects an adult females' estrous cycles might have on alcohol's effects.
What Cha found was that females are less sensitive to alcohol-induced sedation. The female's lesser sensitivity, compared with the adult males, to the behavioral sedative effects of alcohol was most pronounced in the proestrous (the first phase of the estrous cycle, which corresponds to the onset of mating behavior) and diestrous (the last phase of the estrous cycle) states. "We know that females are affected by alcohol differently than males," said co-researcher Scott Swartzwelder, "but unlike many studies, this one shows a way in which females are less sensitive than males. People generally think that alcohol is more potent in females, but that is because women are smaller than men and it generally takes fewer drinks for them to become impaired. Our study shows that when you control for that, and just look at the potency of alcohol on the brain mechanisms that cause sedation, females actually appear to be less sensitive to alcohol. Furthermore, the study emphasizes the need to explore how factors associated with the estrous cycle [menstrual cycle] may mediate this effect."
While the study also showed that adolescent male and female rats are similarly sedated by alcohol, adult rats are not. "This result suggests that as humans mature from adolescence to adulthood, women may become less sensitive to alcohol-induced sedation than men do. This change may have consequences for the ability of an adult woman to physiologically gauge how impaired she is becoming as she drinks," explained Cha. "Although we live in a society that favors equality between the sexes, men and women are not equal when it involves being affected by alcohol. In particular, this study's findings suggest that women - as the gender less affected by alcohol's sedative effects - should take greater care when gauging how much they have had to drink."
The researchers concluded that hormonal fluctuations - or substances affected by those hormonal fluctuations, such as neurosteroids - may play a role in mediating the differences in alcohol tolerance.
Source: Duke University Medical Center