acetaldehyde

Official websites use .gov A .gov website belongs to an official government organization in the United States. Secure .gov websites use HTTPS A lock ( Lock Locked padlock icon ) or means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites. Drinking heavily puts people at risk for many adverse health consequences, including alcohol use disorder, liver damage, and various cancers. But some people appear to be at greater risk than others for developing these problems. Why do some people drink more than others? And why do some people who drink develop problems, whereas others do not? Alcohol is metabolized by several processes or pathways. The most common of these pathways involves two enzymes—alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH). These enzymes help break apart the alcohol molecule, making it possible to eliminate it from the body. First, ADH metabolizes alcohol to acetaldehyde, a highly toxic substance and known carcinogen.1 Then, acetaldehyde is further metabolized by ALDH to another, less active byproduct called acetate,1 which then is broken down into water and carbon dioxide for easy elimination.2 The enzymes cytochrome P450 2E1 (CYP2E1) and catalase also break down alcohol to acetaldehyde. However, CYP2E1 only is active after a person has consumed large amounts of alcohol, and catalase metabolizes only a small fraction of alcohol in the body.1 Small amounts of alcohol also are removed by interacting with fatty acids to form compounds called fatty acid ethyl esters (FAEEs). These compounds have been shown to contribute to damage to the liver and pancreas.3 The chemical name for alcohol is ethanol (CH3CH2OH). The body processes and eliminates ethanol in separate steps. Chemicals called enzymes help to break apart the ethanol molecule into other compounds (or metabolites), which can be processed more easily by the body. Some of these intermediate metabolites can have harmful effects on the body. Most of the ethanol in the body is broken down in the liver by an enzyme called alcohol dehydrogenase (ADH), which transforms ethanol into a toxic compound called acetaldehyde (CH3CHO), a known carcinogen. However, acetaldehyde is generally short-lived; it is quickly broken down to a less toxic compound called acetate (CH3COO-) by another enzyme called aldehyde dehydrogenase (ALDH). Acetate then is broken down to carbon dioxide and water, mainly in tissues other than the liver. Ketoacidosis is a condition where the body cannot metabolize glucose and ketones accumulate in the blood. This condition can occur when someone consumes a large amount of alcohol then does not eat enough due to vomiting, nausea, or disordered eating.11 It can be associated with “drunkorexia,” in which someone limits their food intake to compensate for calories from alcohol consumption. Ketoacidosis can be life-threatening and requires treatment. Certain medications can influence the absorption and metabolism of alcohol. The interaction can result in higher blood alcohol concentrations (BACs) and other adverse effects. Alcohol can also affect the metabolism of certain medications, speeding up or slowing down the clearance of the medication from the body. This altered metabolism lowers or raises levels of the medication in the blood. Alcohol can alter the pharmacological effects of a medication, increasing or decreasing the medication's effects on the body. To learn more, please see Harmful Interactions: Mixing Alcohol With Medications .