Function of Alcohol Dehydrogenase in the Body #
Alcohol dehydrogenase first converts consumed alcohol into acetaldehyde – an intermediate stage that the body must further detoxify. Without this enzyme, alcohol would be significantly less tolerable for humans. The liver and stomach play the main roles, with women on average having less ADH in the stomach than men. As a result, blood alcohol levels rise faster in women.
Why Do People React Differently to Alcohol? #
Several biological factors determine how quickly and effectively a person can break down alcohol. The activity level of this enzyme varies from person to person. Some people metabolise alcohol slowly and experience physical symptoms more quickly. Others appear “hardier” because their body processes alcohol more rapidly. Key influencing factors include:
- genetic variants of ADH and ALDH
- body weight and composition
- diet and zinc status
- tolerance and drinking patterns
- liver and stomach health
In East Asia and some indigenous populations, variants occur that convert alcohol extremely quickly into highly toxic acetaldehyde. At the same time, the detoxification of acetaldehyde is often slowed down in these groups. The result is the well-known “flush reaction” with facial reddening, palpitations, and nausea. This combination can protect against alcohol dependence because drinking quickly becomes unpleasant.
Importance of Zinc for the Enzyme #
Alcohol dehydrogenase is a zinc-containing enzyme. Without zinc, the active site functions less efficiently. A pronounced zinc deficiency can therefore slow alcohol metabolism and intensify symptoms.
The Body’s Reactions to Chronically High Alcohol Consumption #
With persistently high amounts, the body activates a second degradation pathway that produces more aggressive oxygen compounds and places additional strain on the liver. At the same time, alcohol disrupts energy metabolism:
- blood sugar can drop more sharply
- fats are stored more easily
- lactic acid can rise faster
ADH and Its Role in Methanol and Ethylene Glycol Poisoning #
Alcohol dehydrogenase metabolises not only ethanol but also methanol and ethylene glycol. However, this produces highly toxic substances. In such emergencies, the enzyme is deliberately inhibited so that these toxins are not formed until the body can excrete the original substances.
Conclusion #
Alcohol dehydrogenase determines how quickly alcohol is broken down and how strongly it affects the body and well-being. A high alcohol tolerance is therefore not a sign of good health, but rather the expression of biochemical particularities that can have consequences for the liver, metabolism, and the risk of dependence.
In brief
Alcohol dehydrogenase (ADH) is the most important enzyme for breaking down alcohol. It determines how quickly the body processes ethanol, how much acetaldehyde is produced, and why people tolerate alcohol differently.
Frequently Asked Questions about Alcohol Dehydrogenase (FAQ) #
Can the activity of alcohol dehydrogenase be increased?
Not in a targeted way. The body works within its individual limits. Neither coffee nor cold showers noticeably speed up the breakdown. What matters most are liver health, zinc status, and the time the body needs.
No. People who break down alcohol quickly feel the effects less and often drink more, which puts long-term strain on the liver and can increase the risk of dependence.Is high alcohol tolerance a sign of good health?
This is usually due to a combination of fast ADH and slow ALDH. Acetaldehyde accumulates more quickly and triggers typical symptoms such as reddening of the face, palpitations, and nausea.Why do some people experience flushing and nausea after small amounts of alcohol?
Yes. Zinc stabilises the enzyme and is essential for the reaction. A significant zinc deficiency can worsen alcohol tolerance.Does zinc really play a role in alcohol metabolism?
Bernd Guzek, MD, PhD #
Physician, author & co-founder of Bye-Bye-Booze
Specialized in biochemical mechanisms of addiction and brain metabolism.
