Next Lesson - Oxidative Stress
Abstract
- Alcohol is a molecule with a very high energy content that is metabolised by enzymes in the liver.
- The limiting factor in alcohol metabolism is aldehyde dehydrogenase.
- The consumption of excess alcohol can lead to a build-up of acetaldehyde causing a hangover in the short term and liver damage in the long term.
- The build up of acetaldehyde can be exploited when trying to treat alcoholism as the drug disulfiram inhibits aldehyde dehydrogenase to induce hangover symptoms by causing this build-up to occur.
Core
Alcohol has higher energy content than carbohydrates, and so excess alcohol consumption can lead to excess fat in the body as the alcohol is not fully used for energy and is converted into fat.
Alcohol is measured in units instead of grams, and 1 unit (25ml in the UK) contains 8g of alcohol. The weekly limit in the UK for both genders is 14 units.
Over 90% of alcohol consumed is oxidised in the liver according to this equation:
Diagram - The process of alcohol metabolism
SimpleMed original by Maddie Swannack
The limiting factor in the equation is aldehyde dehydrogenase. This means when excess alcohol is consumed, it is all converted into acetaldehyde. However, not all can be converted into acetate at the same rate, meaning that acetaldehyde builds up. This is bad because acetaldehyde is toxic, leading to the effects of a hangover once the alcohol has been metabolised. Long term exposure to acetaldehyde causes hepatitis and then cirrhosis, leading to liver damage.
Liver damage can also occur if there is inadequate NAD+, as when acetate builds up it can cause lactic acidosis, gout, hypoglycaemia and cirrhosis. This relates to glutathione and oxidative stress.
Disulfiram is an inhibitor of aldehyde dehydrogenase and is used to treat alcoholism. Drinking alcohol when taking disulfiram causes an extreme build-up of acetaldehyde, causing severe hangover-type symptoms. This discourages the consumption of alcohol by the individual by classical conditioning so it can be used to help treat alcohol dependence.
Edited by: Dr. Ben Appleby
Reviewed by: Dr. Thomas Burnell
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