How is alcohol broken down by the body?

Answer: Alcohol is processed and by two enzymes in the liver, resulting in acetate.

alcohol metabolism

When we drink alcohol, the blood rapidly absorbs the alcohol from the stomach lining and small intestines. Once it the bloodstream, alcohol can easily pass through the blood - brain barrier since it is a small molecule with a low molecular weight. When in the brain, alcohol can start to affect different parts of the brain, which explains why we experience intoxication symptoms such as euphoria, lightheadedness, or poor balance.

Alcohol that is circulating in the bloodstream will pass through the liver for metabolic processing. There are two major enzymes that are responsible for breaking down alcohol into a non psychoactive substance.

Step 1: Ethanol (alcohol) is converted to acetaldehyde by alcohol dehydrogenase (ADH). This end result of this step is the toxic acetaldehyde, which is far more poisonous than alcohol. High levels of acetaldehyde can result in a headache, nausea, or vertigo.

Step 2: Acetaldehyde dehydrogenase is converted to acetate, or acetic acid, by acetaldehyde dehydrogenase (ALDH). The end product of this reaction is the harmless compound acetate. The expression or function of this enzyme in this reaction is dependent on genetics. Many people of Asian descent have less of the enzyme than others; the accumulation of formaldehyde is one explanation of the “Asian flush,” a change in appearance of some Asians after drinking alcohol.

The second step of alcohol metabolism is targeted by the drug disulfiram. Disulfiram, or Antabuse, inhibits the function of acetaldehyde dehydrogenase, which leads to an elevation of acetaldehyde after a person drinks alcohol.