How alcohol may boost risk of cancer
Nearly 30 years after discovery of a link between alcohol consumption and certain forms of cancer, scientists now have the first evidence from research on humans that explains how the popular beverage may be carcinogenic.
The results also suggested that people of Asian descent, Native Americans and native Alaskans are more prone to cancer risk from alcohol consumption.
Silvia Balbo, Ph.D., who led the study, explained that the human body breaks down, or metabolizes, the alcohol in beer, wine and hard liquor. One of the substances formed in that breakdown is acetaldehyde, a substance with a chemical backbone that resembles formaldehyde.
Formaldehyde is a known human carcinogen. Scientists also have known from laboratory experiments that acetaldehyde can cause DNA damage, trigger chromosomal abnormalities in cell cultures and act as an animal carcinogen.
"We now have the first evidence from living human volunteers that acetaldehyde formed after alcohol consumption damages DNA dramatically," said Balbo, a research associate in the laboratory of Stephen Hecht, Ph.D., a noted authority on cancer prevention at the University of Minnesota.
"Acetaldehyde attaches to DNA in humans to the genetic material that makes up genes in a way that results in the formation of a 'DNA adduct.' It's acetaldehyde that latches onto DNA and interferes with DNA activity in a way linked to an increased risk of cancer," she explained.
Balbo pointed out that people have a highly effective natural repair mechanism for correcting the damage from DNA adducts.
Most people thus are unlikely to develop cancer from social drinking, although alcohol is associated with a risk of other health problems and accidents. In addition, most people have an enzyme called alcohol dehydrogenase, which quickly converts acetaldehyde to acetate, a relatively harmless substance.
However, about 30 percent of people of Asian descent have a variant of the alcohol dehydrogenase gene and are unable to metabolize alcohol to acetate. That genetic variant results in an elevated risk of esophageal cancer from alcohol drinking. Native Americans and native Alaskans have a deficiency in the production of that same enzyme.
The results were reported at the 244th National Meeting and Exposition of the American Chemical Society.