Research using human cell cultures and mice suggests that those with an uncommon variation of the aldehyde dehydrogenase 2 gene (ALDH2) may be more at risk of Alzheimer's if they consume alcohol. This gene variation is associated with facial redness following alcohol consumption, reflecting reduced activity of an enzyme that protects against a toxin produced by alcohol consumption (acetaldehyde). Flushing, and inflammation, is a response to the toxin.

The gene variant occurs in about 8% of the world’s population, but is particularly prevalent among people from East Asia, where nearly half the population carries it.

The research builds on previous epidemiological studies in East Asian populations that have previously suggested an association between the mutation in ALDH2 that causes facial flushing and Alzheimer’s disease. However, there have also been other studies that didn’t find an association.

Confirmation of these results requires large epidemiological studies of humans to see whether alcohol drinkers who have the mutation develop Alzheimer’s disease at a higher-than-average rate.

The gene variant is also associated with a higher risk of developing cancer in the esophagus.