Individuals with the gene responsible for "Asian glow," which causes skin to flush red when drinking alcohol, may induce more DNA damage when they imbibe, a new study has found.
The body converts alcohol into acetaldehyde, a toxin that can damage DNA, before processing it into an energy source, according to Ketan J. Patel, the lead author of the study, published earlier this month in the journal Nature. But approximately 560 million people of East Asian descent carry a mutated gene responsible for encoding aldehyde dehydrogenase 2 (ALDH2), the enzyme that breaks down acetaldehyde, rendering it ineffective.
The mutated gene is defective at breaking down acetaldehyde and is associated with higher incidences of esophageal cancer, heart attacks and osteoporosis, compared to the general population.
Individuals with the flushing gene depend on a second protection mechanism that repairs DNA, but this system is not perfect or failsafe, Patel said.
British researchers studied genetically-engineered mice that lacked either the enzyme that processes acetaldehyde, the DNA repair mechanism or a combination of both. They exposed mice to a dose of alcohol equivalent to a human drinking 750 milliliters of whisky and found that those lacking just the enzyme incurred four times more DNA damage than normal mice. With their DNA repair system intact, however, most of the damage was resolved.
In mice without either of the protection mechanisms, the same amount of alcohol led to significant rearrangement of the chromosomes.
"A cell cannot become cancerous unless it alters genes," Patel said. "To alter genes you need to alter DNA. So our work shows that alcohol is converted into a chemical that alters DNA in quite profound ways. It gives you a most direct and obvious connection of how alcohol consumption can cause cancer."
Though the study was conducted on mice, Patel said he is confident that the findings apply to humans.
It is not understood why those who carry the flushing gene turn red after drinking, Patel noted, though it is likely a warning signal to the body that an individual is harming their cells.
"Imagine if you are an Asian flusher and you binge drank every week, and you did that for 30 years," Patel said. "That's like having one dose of chemotherapy a week for 30 years."
He added that alcohol damage may be cumulative over the period that an individual exposes themselves to it, though it remains unknown whether the chronic intake of alcohol would alter the quality of old age.
The new research provides information that contributes to the public debate about health and alcohol, Patel said, noting that discussions about how alcohol causes damage have been controversial.
"This new paper now shows exactly how when alcohol is processed that it results in DNA damage, how this damage is repaired and how this damage alters the DNA of stem cells - the all important cell type that allows organs to regenerate," he said.