Have you ever wondered why a woman and a man can consume the same amount of alcohol, yet the woman may appear to become intoxicated sooner?
There are several biological and physiological reasons for this difference. However, it is important to stress that not every woman will become drunk faster than every man. Factors such as body size, body composition, food intake, drinking speed, medications, genetics and alcohol tolerance can all influence how quickly alcohol affects an individual.
On average, however, women tend to develop a higher blood alcohol concentration (BAC) than men after consuming the same amount of alcohol.
- Women generally have less body water
One of the main explanations is the difference in body composition.
Alcohol is distributed primarily through water in the body rather than fat. Women generally have a higher percentage of body fat and a lower proportion of body water than men of the same weight.
Consequently, when a man and woman of similar weight consume an equal amount of alcohol, the alcohol may be distributed through a smaller volume of body water in the woman’s body. This can result in a higher concentration of alcohol in her bloodstream.
The National Institute on Alcohol Abuse and Alcoholism (NIAAA) identifies differences in body water as one of the key reasons women tend to reach higher BAC levels than men after consuming the same quantity of alcohol.
- Body size can influence BAC
A person’s size and weight also affect how alcohol is distributed throughout the body.
Men are, on average, larger and tend to have more muscle mass and body water than women. Since alcohol is distributed mainly through body water, these differences can influence the concentration of alcohol in the blood.
However, being larger does not make someone immune to alcohol’s effects. The quantity consumed and the speed at which it is consumed remain important.
- Alcohol may be absorbed and processed differently
Differences in the way alcohol is absorbed and metabolised may also contribute to higher BAC levels among women.
The Centers for Disease Control and Prevention (CDC) notes that women generally absorb more alcohol and may take longer to process it than men. This can contribute to higher blood alcohol levels after consuming the same amount.
Researchers have also examined “first-pass metabolism”, which refers to the breakdown of some alcohol before it reaches the bloodstream. Some studies have found differences in gastric alcohol dehydrogenase activity between men and women.
However, this does not simply mean that women’s bodies “cannot break down alcohol” as effectively as men’s. Alcohol metabolism varies significantly from one person to another.
- Drinking on an empty stomach can make alcohol take effect faster
Food intake is another important factor.
When alcohol is consumed on an empty stomach, it can enter the bloodstream more rapidly. Eating before or while drinking can slow the rate of alcohol absorption, although food does not stop alcohol from entering the bloodstream.
This means two people who consume the same amount of alcohol can experience noticeably different effects depending on whether they have eaten.
- Drinking quickly can raise BAC rapidly
The speed at which alcohol is consumed also matters.
Although the body begins metabolising alcohol soon after it is consumed, alcohol generally enters the bloodstream faster than the body can process it. As a result, consuming several drinks within a short period can cause alcohol to accumulate in the bloodstream and raise BAC.
The NIAAA defines binge drinking as a pattern of drinking that typically raises BAC to “0.08% or higher”. For a typical adult, this generally corresponds to about four or more drinks for women or five or more drinks for men within approximately two hours.
These are population-level definitions and do not mean that everyone will become intoxicated after consuming that exact amount.
Sex is only one part of the picture
On average, women may reach higher BAC levels and experience the effects of alcohol more quickly or for longer than men after consuming the same amount.
But biological sex is only one factor.
Body size, food intake, drinking speed, medications, hormones, genetics and previous drinking experience can all affect how alcohol impacts an individual. Similar differences can also occur among men.
There is therefore no universal number of drinks that will make everyone equally intoxicated.
Drinking less, consuming alcohol more slowly and avoiding driving after drinking are safer choices regardless of sex.
The difference also goes beyond simply asking who “gets drunk first”. Research indicates that women can experience certain alcohol-related health problems at lower levels of alcohol exposure than men, highlighting the importance of understanding how alcohol affects different bodies.
By: Prince Martey-Sogar.