WEDNESDAY, Aug. 22, 2012 (HealthDay News) -- A new study provides insight on how alcohol may increase cancer risk. When the body metabolizes -- or breaks down -- alcohol, a substance called acetaldehyde is formed, which can cause DNA damage, researchers say.
Acetaldehyde's chemical makeup is similar to the known carcinogen formaldehyde, according to the researchers.
"We now have the first evidence from living human volunteers that acetaldehyde formed after alcohol consumption damages DNA dramatically," study leader Silvia Balbo, a research associate at the University of Minnesota in Minneapolis, said in an American Chemical Society news release.
Acetaldehyde attaches to DNA, interfering "with DNA activity in a way [that is] linked to an increased risk of cancer," Balbo explained. The bits of DNA attached to cancer-causing chemicals are known as adducts.
For the study, the researchers gave 10 volunteers increasing doses of vodka once a week for three weeks. They found that levels of DNA adducts increased up to 100 times in participants' oral cells within hours after each dose. These levels dropped about 24 hours later.
The study authors pointed out, however, that most people who drink socially do not develop cancer because they are equipped with a natural repair system. Most people have an enzyme known as alcohol dehydrogenase, which converts acetaldehyde to a harmless substance known as acetate.
But certain people are not able to convert acetaldehyde to acetate because they have a variant of the alcohol dehydrogenase gene, the researchers noted. As a result, they are more likely to develop esophageal cancer from drinking alcohol. About 30 percent of people of Asian descent have the variant. Native Americans and Native Alaskans also have a deficiency in the production of this enzyme, they said.
The findings were scheduled to be presented Wednesday at the American Chemical Society's annual meeting in Philadelphia. The data and conclusions of research presented at medical meetings should be viewed as preliminary until published in a peer-reviewed journal.
The U.S. Centers for Disease Control and Prevention has more about alcohol and public health.