Alcohol is broken down in the liver with the help of enzymes. Learn how alcohol is converted to the toxic byproduct acetaldehyde before being oxidized into acetate with help from the enzymes alcohol dehydrogenase and aldehyde dehydrogenase in this lesson.
Blood Alcohol Concentration
There’s no question that alcohol has the ability to change your body.
This change can be felt, and it can also be detected in the blood within minutes of having your first alcoholic drink. If you continue to drink alcoholic beverages, your blood alcohol concentration (BAC), which is the measure of alcohol in your blood, will continue to rise – when it exceeds .08 percent you are legally intoxicated.So, now that the alcohol is in your system, how do you get rid of it? Well, there are a lot of theories about how to sober up quickly, like drinking coffee or taking a cold shower, but in reality the only way to return your BAC back to zero is to allow your liver time to metabolize, or process and break down, the alcohol. In this lesson, we will learn how alcohol is handled by your body and how it is broken down.
Alcohol is not handled by your body in the same way as food nutrients, like carbohydrates, proteins and fats. In a way, alcohol is looked at as an unwelcome house guest, and as soon as your body detects it, it sets to work trying to get rid of it. This is partly because your body doesn’t have anywhere to store it. If you didn’t metabolize it quickly, it would just build up, causing damage to your cells and tissues. In fact, your body wants to expel this unwanted guest so badly that it pays less attention to other nutrients in your digestive tract and concentrates more of its energy on breaking down alcohol.We see that your body jumps into action as soon as the substance hits your stomach.
Alcohol, unlike other nutrients, is able to be absorbed through your stomach lining. This means alcohol has a fairly straight shot right into your bloodstream, which is why it can be detected in the blood within minutes. Alcohol that doesn’t pass through your stomach lining continues into the next area of the digestive tract, known as the small intestine, where it’s absorbed into the blood alongside other nutrients that happen to be in your system.
Alcohol that is now in your blood finds its way to the liver, which is the main site of alcohol metabolism.
Alcohol enters your liver, and most of it follows the main metabolic pathway that occurs in two steps. First we see the alcohol, or more specifically the drinkable form of alcohol called ethanol, is oxidized into acetaldehyde. This is a toxic byproduct of alcohol metabolism. While this byproduct only exists for a short time before it’s further broken down, its toxicity is the focus of much of the research as to why alcohol negatively affects the liver and the rest of the body.This initial metabolic step in the breakdown of alcohol is helped along by alcohol dehydrogenase, which is the enzyme that catalyzes the conversion of ethanol to acetaldehyde. We know that this is an enzyme because it ends in the suffix ‘ase,’ which is a common way biochemists label substances to denote that they are enzymes.
So, it might help you to remember this term if you think of alcohol dehydrogenase as the alcohol enzyme. Enzymes work by catalyzing reactions, which simply means they give reactions a boost and help them move along at a faster rate.Now, I mentioned that acetaldehyde is not something your body wants, so this compound goes through the second step of alcohol metabolism. This involves a second oxidation reaction that metabolizes acetaldehyde into acetate, which is a less toxic byproduct of alcohol metabolism. This conversion is given a boost from aldehyde dehydrogenase, which is the enzyme that catalyzes the conversion of acetaldehyde to acetate.
In other words, it’s the aldehyde enzyme.Acetate can then be completely broken down into carbon dioxide and water that you easily expel from your body when you breathe out and go to the bathroom. When you stop drinking and the liver has had enough time to fully metabolize the alcohol, your blood alcohol concentration goes back to zero.
Let’s review. Your blood alcohol concentration (BAC), which is the measure of alcohol in your blood, rises as you drink alcohol. Over time, your liver, which is the main site of alcohol metabolism, breaks down the alcohol, returning your BAC to zero.In the first step of alcohol metabolism, ethanol, which is the drinkable form of alcohol, is oxidized into acetaldehyde, a toxic byproduct of alcohol metabolism.
This reaction is helped along by alcohol dehydrogenase, which is the enzyme that catalyzes the conversion of ethanol to acetaldehyde.In the second step, acetaldehyde is oxidized into acetate, which is a less toxic byproduct of alcohol metabolism. This conversion is given a boost from the enzyme aldehyde dehydrogenase. Acetate can then be completely broken down into carbon dioxide and water that you easily expel from your body.
This video on alcohol should help you to understand how to:
- Recognize what blood alcohol concentration is
- Describe how the human body reacts to alcohol in its system
- Analyze how alcohol metabolism works in the body