A federal research team has discovered more clues behind the long-suspected role of the carcinogen acetaldehyde in the link between alcohol consumption and some forms of cancer.

Researchers at the National Institute on Alcohol Abuse and Alcoholism (NIAAA) and the National Institute of Standards and Technology report that natural compounds called polyamines react with acetaldehyde – which is formed as the body metabolizes alcohol – to generate reactions that damage DNA. This can lead to the formation of cancer.

“This work provides an important framework for understanding the underlying chemical pathway that could explain the association between drinking and certain types of cancer,” said NIAAA director Ting-Kai Li, M.D. Alcohol consumption has been associated with increased risk of upper gastrointestinal cancer and other cancers.

Polyamines, which are essential for cell growth, generally protect DNA from damage. But researchers found that when these compounds react with acetaldehyde, they facilitate its conversion to crotonaldehyde, which has been shown to cause cancer in animals.

“We were able to demonstrate that these reactions can take place with acetaldehyde concentrations that have been measured in human saliva during alcohol consumption,” said lead NIAAA researcher P.J. Brooks, Ph.D.