People whose faces turn red when they drink alcohol may be facing more than embarrassment. The flushing may indicate an increased risk for a deadly throat cancer, researchers report.
The flushing response, which may be accompanied by nausea and a rapid heartbeat, is caused mainly by an inherited deficiency in an enzyme called ALDH2, a trait shared by more than a third of people of East Asian ancestry — Japanese, Chinese or Koreans. As little as half a bottle of beer can trigger the reaction.
The deficiency results in problems in metabolizing alcohol, leading to an accumulation in the body of a toxin called acetaldehyde. People with two copies of the gene responsible have such unpleasant reactions that they are unable to consume large amounts of alcohol. This aversion actually protects them against the increased risk for cancer.
But those with only one copy can develop a tolerance to acetaldehyde and become heavy drinkers.
“What we’re trying to do here is raise awareness of this risk factor among doctors and their ALDH2-deficient patients," said Dr. Philip J. Brooks, an investigator with the National Institute on Alcohol Abuse and Alcoholism, and an author of the report published on Monday in the journal PLoS Medicine. “It’s a pretty serious risk."
The malignancy, called squamous cell esophageal cancer, is also caused by smoking and can be treated with surgery, but survival rates are very low. Even moderate drinking increases the risk, but it rises sharply with heavier consumption. An ALDH2-deficient person who has two beers a day has six to 10 times the risk of developing esophageal cancer as a person not deficient in the enzyme.
Reducing drinking can significantly reduce the incidence of this cancer among Asian adults. The researchers calculate that if moderate- or heavy-drinking ALDH2-deficient Japanese men reduced their consumption to under 16 drinks a week, 53 percent of esophageal squamous cell cancers in that group could be prevented.
There is some anecdotal evidence that young people treat the flushing as a cosmetic response to be countered with antihistamines while continuing to drink. Ignoring the symptom and continuing to drink is likely to increase the incidence of esophageal cancer, researchers said.
To determine risk, doctors can ask their patients two simple questions. First, do you flush after drinking a glass of beer? Second, in the first one or two years after you began drinking, did you flush after having a beer?
The second question covers the possibility that a person has become tolerant to the effect.
Dr. Brooks said that the two questions give doctors an easy way to find out if the patient is ALDH2-deficient. There is also a patch test in which an ethanol-soaked pad is applied to the skin. If it causes reddening after 10 or 15 minutes, there is a high likelihood that the person is ALDH2-deficient.
