If you've ever seen someone turn bright red after a single sip of beer, you've witnessed the ALDH2 deficiency in action. A landmark study from Seoul National University mapped precisely how this variant disrupts alcohol metabolism, confirming it as one of the strongest single-gene effects on human behaviour ever documented. Roughly 540 million people worldwide carry this variant, most of them in East Asia.
The assembly line that breaks down
Normal alcohol processing works in two steps. Your liver converts ethanol into acetaldehyde, a toxic compound. Then an enzyme called ALDH2 breaks acetaldehyde down into harmless acetate.
In people with the ALDH2*2 variant, that second step barely functions. Acetaldehyde accumulates rapidly, triggering facial flushing, nausea, rapid heartbeat, and sometimes dangerous drops in blood pressure.
Beyond discomfort: a serious health issue
Accumulated acetaldehyde is a known carcinogen, and ALDH2-deficient individuals who drink regularly face oesophageal cancer risks up to ten times higher than the general population.
The evolutionary puzzle
Why has such an apparently disadvantageous gene persisted in hundreds of millions of people? Some evidence suggests it offered protection against parasitic infections in ancient rice-farming communities.
Do you carry this variant?
FuelYourDNA analyses the ALDH2*2 variant (rs671) in your DNA profile. If you carry it, your report specifies this, and your nutritional recommendations account for it:
- N-acetylcysteine (glutathione precursor for toxin neutralisation)
- B vitamins for liver support
- Antioxidants tailored to your detoxification profile
Scientific References
Scientific studies cited are published in peer-reviewed journals.
- Main source: Seoul National University, The Lancet Gastroenterology & Hepatology, 2024.
- Brooks PJ, et al. (2009). The alcohol flushing response: an unrecognized risk factor for esophageal cancer from alcohol consumption. PLoS Medicine, 6(3), e50. PubMed 19226188
- Yokoyama A, et al. (1998). Esophageal cancer and aldehyde dehydrogenase-2 genotypes in Japanese males. Cancer Epidemiology, Biomarkers & Prevention, 7(11), 971–976. PubMed 9829701
- Edenberg HJ. (2007). The genetics of alcohol metabolism. Alcohol Research & Health, 30(1), 5–13. PubMed 17718394