KLOTHO-VS Report Now Available for Health Intelligence Members!


Not sure what to eat?

Get a custom nutrition plan.

Start Here

Aldehyde dehydrogenase 2 (ALDH2) is an enzyme encoded for by the ALDH2 gene 1.  ALDH2 catalyzes the chemical breakdown of acetaldehyde into acetic acid, which is less harmful to the body and can be excreted.

Acetaldehyde is commonly formed from the breakdown of ethanol and is the byproduct associated with hangover symptoms and skin flushing following excessive alcohol consumption.

ALDH2 and alcohol metabolism

Aldehyde Dehydrogenase 2 plays a crucial role in alcohol metabolism. Specifically, it converts acetaldehyde, a toxic byproduct of alcohol metabolism, into acetic acid.

This enzyme is a key factor in the breakdown of alcohol in the body and helps to eliminate the toxic effects of acetaldehyde.

There is one SNP in ALDH2 which is associated with impaired outcomes.


Science Grade
Immune Health
rsID Number Major Allele Minor Allele Minor Allele Frequency (%) Major Amino Acid Minor Amino Acid
rs671 g a 1.8 Glu Lys

Risk Description

rs671 is a widely recognized SNP, distinguished by the phenomenon referred to as “alcohol flush,” also acknowledged as “Asian Flush” or “Asian blush.”

This occurrence is prevalent among certain individuals, frequently of Asian heritage, who experience facial, neck, and sometimes shoulder reddening following alcohol consumption.

The risk ‘A’ allele of the SNP rs671 in ALDH2 is associated with reduced ALDH2 activity making carriers more likely to experience alcohol flush, and bad hangover symptoms even with a relatively low intake of alcohol 2. However other foods sources such as coffee, fermented foods, dairy products and certain processed foods can also contain high levels of acetaldehyde 3.4.

Conversely, the presence of the G allele is linked to heightened alcohol consumption due to its association with more rapid clearance of acetaldehyde from the bloodstream.

Indirect Nutrients:*

Ingredient Active Ingredient Effect

Glutathione is an important antioxidant in its own right, but is also used by also used by several antioxidant proteins as a cofactor 5.

When glutathione is hydrolysed the product cysteinylglycine is formed which has been shown to strongly bind with acetaldehyde, reducing its harmful impact and allowing its excretion from the body 6.

As such increasing glutathione intake may result in an overall increase in antioxidant capacity, and also help reduce the impact of acetaldehyde.

Nutritional Contraindications:*

Ingredient Active Ingredient Effect
Foods rich in acetlyaldehyde

While the metabolism of alcohol is a major source of acetaldehyde there are numerous other foods which also contain significant levels with coffee and certain fermented foods being particularly rich sources. For those with reduced ALDH2 activity reducing the intake of these foods may prove beneficial 3.4.

Alcohol Ethanol

Those carrying the A allele of rs671 are best advised to avoid alcohol altogether. Although the flushing common with carriers of the A allele may seem harmless, it is a sign that alcohol is especially toxic for these people. Although rs671 A carriers often avoid alcohol due to unpleasant side effects, if these individuals do regularly consume alcohol, their risk of certain cancers, including colon cancer increases.

Discuss this information with your doctor before taking any course of action.


Get the very latest on genetics, nutrition and supplements delivered to your inbox

Facebook icon Twitter icon Instagram icon Pinterest icon Google+ icon YouTube icon LinkedIn icon Contact icon Info icon Email icon Phone icon Pin icon
Back to top