The effects of alcohol beverages on your body depend on who you are, how you drink, and what you drink. There are many factors that influence how alcohol affects you.
Absorption. When you drink an alcohol beverage, it immediately begins to be absorbed into your bloodstream, partly from your stomach and more actively from your small intestine. When drinking alcohol beverages, adding water or other drinks without alcohol will dilute the alcohol in your stomach and will slow absorption. Eating food will also slow alcohol absorption.
Blood alcohol concentration (BAC) can be measured with a blood test. Blood alcohol can also be approximated with a breath test, since some of the alcohol from the blood passing through your lungs is released when you exhale. A small amount of the alcohol is also released in urine.
While the rate of absorption may change depending on what you ate and what else you drank, you cannot stop the alcohol from entering your system.
Once the alcohol hits your bloodstream, it affects every organ and part of your body, including the brain—where the alcohol produces intoxication. The more you drink and the faster you drink, the more alcohol enters your blood. BAC increases much faster when drinking on an empty stomach. Eating food while drinking will slow absorption and moderate your BAC.
The concentration of alcohol in your body depends not only on how much you drink, but also on your body. First, your weight matters. Larger people have a larger body to absorb the alcohol, so they may have a lower BAC while someone smaller will have a higher BAC from the same amount of alcohol. Second, your gender matters. Compared to men, women have a lower portion of their bodies that is water-based and can therefore reach a higher BAC more quickly from the same amount of alcohol.
So when women consume the same amount of alcohol at the same rate as men, they reach a higher BAC more quickly. In general, women will feel the effects sooner than men drinking the same amounts. Their bodies will also be affected more than men’s bodies.
Metabolism. Your body breaks down alcohol into other substances that the body can use for energy. This breakdown process is called metabolism, and also occurs with food. But the way your body processes alcohol is unique because most of the metabolism occurs in your liver. Here is the short story: In your liver, alcohol is converted first into a number of different compounds. One of these compounds is called acetaldehyde. This organic compound occurs naturally in coffee, bread, and ripe fruit, but is unhealthy when consumed in larger quantities. Fortunately, acetaldehyde is further converted into a non-harmful substance called acetate (or acetic acid), which is eventually turned into carbon dioxide and water and is eliminated from the body.
This breakdown happens primarily in the liver through the action of special molecules called enzymes. On average, a person metabolizes 10-12g of alcohol an hour.
The concentration of these enzymes and their ability to metabolize alcohol varies among individuals. For example, in some people, their genetics may reduce the activity of these enzymes. Also, women generally have lower levels of the enzymes that metabolize alcohol compared with men. This is one reason why women generally reach a higher BAC and can become more impaired than men after drinking the same amount of alcohol. Finally, there are other considerations, such as age and health, that also can affect how quickly you process alcohol.
Since your body can absorb alcohol faster than it can metabolize it, alcohol can build up in your bloodstream. If you drink faster than you metabolize your drinks, your BAC level rises more quickly, and the effects of alcohol increase. The more you drink, the more time it will take for the alcohol to be eliminated from your system.
Alcohol acts as a diuretic, meaning that when your body breaks down alcohol, it triggers your body to remove water from your blood through your urine. That is why it is a good idea to drink water and other non-alcohol drinks along with your alcohol beverage to avoid dehydration. Dehydration contributes to the unpleasant effects of excessive drinking that are associated with a “hangover.” To decrease the risk of a hangover, make sure you get in the habit of drinking some water with every drink of an alcohol beverage.
Excessive drinking also results in more acetaldehyde in your body. Those who drink excessively on a regular basis have higher risks of dangerous health effects.
BAC levels are important, but they don’t tell the whole story of how alcohol affects you. Your age and health status, mood, and any medications or drugs that you may be taking are all factors. Your reaction also depends upon the situation you are in and even your expectations about how alcohol affects you.
Drinking patterns and risk. Most people who drink do so in a way that enhances their enjoyment of life, but there are others who may drink irresponsibly – occasionally or regularly – and create health and social problems for themselves and others. That’s why risk is not just a result of how much you drink, but also of when and how you drink. It is quite different to have one drink with dinner every day of a week, for example, than to quickly down seven drinks in rapid succession in a single evening. Health experts call this rapid and excessive consumption “binge drinking,” which is potentially dangerous. A repeated pattern of binge drinking is especially bad for your health.
Because people are different, what is “too much” may vary by individual. Many countries have established drinking guidelines that help people avoid risks associated with excessive drinking. Additionally, health experts have also developed various tests that you may use to assess if your drinking may be a problem. There are two commonly used screening tools, the CAGE and the AUDIT. Developed at the University of North Carolina, CAGE is a commonly used international assessment tool consisting of only four questions. The AUDIT questionnaire is part of a larger comprehensive evaluation available from the World Health Organization.