How does our body break down alcohol?

Alcohol is a cell poison. From the first sip, our metabolism does everything it can to remove the alcohol from our body as quickly as possible. Some alcohol is excreted through the kidneys, lungs and skin. However, the most important organ for detoxifying our body and therefore the main site for breaking down alcohol is the liver.

In the liver cell, alcohol is converted into acetaldehyde by a specific enzyme, alcohol dehydrogenase (ADH). Acetaldehyde is very toxic and is responsible for the carcinogenic effects of alcohol. If we feel bad after drinking, experience nausea, headaches or dizziness, acetaldehyde is the cause. While alcohol is intoxicating, acetaldehyde causes a hangover.

In a second step, acetaldehyde is converted in the liver into the less toxic acetic acid by the enzyme acetaldehyde dehydrogenase. In a further metabolic step, acetic acid is broken down into carbon dioxide and water and excreted.

The two key enzymes for the breakdown of alcohol are alcohol dehydrogenase (ADH) and acetaldehyde dehydrogenase (ALDH).

Have you ever thought about why there are people who lie under the table after a glass of wine, while others can drink liters without staggering?

This is because the metabolic steps required to break down alcohol do not occur equally efficiently in all people. On the one hand, there are people who, for genetic reasons, produce less of the key enzymes ADH and ALDH, which are necessary for breaking down alcohol. This mainly includes Asians. These people therefore get drunk more quickly and feel the unpleasant consequences of alcohol poisoning more acutely. In contrast, people who appear to “tolerate” alcohol well are often regular consumers of alcoholic beverages. When you consume alcohol regularly, your metabolism changes and your liver increases its capacity to break down alcohol. The enzyme ADH is increasingly produced. In addition, another metabolic pathway is activated, the so-called MEOS system, in which alcohol is converted into acetaldehyde via a further step. Alcohol has an intoxicating effect. So if alcohol breaks down into acetaldehyde more quickly, you're less likely to feel drunk. BUT no less acetaldehyde accumulates in the body when alcohol is broken down more quickly. And since acetaldehyde is toxic to our bodies and carcinogenic, regular drinkers have a correspondingly higher risk of suffering from the consequences.