There is a growing body of research linking alcohol consumption to an increased risk of cancer, and now a team of scientists at the UK Medical Research Council’s Laboratory for Molecular Biology believe they have found a plausible explanation.
In the mouse study, after giving them dilute alcohol, chemically known as ethanol, they used chromosome analysis and DNA sequencing to examine the genetic damage caused by acetaldehyde, a harmful chemical produced when the body processes alcohol, finding that alcohol damaged the DNA in blood-forming stem cells because of this by-product of the alcohol metabolism process, acetaldehyde.
Acetaldehyde can damage and cause double-stranded breaks in the DNA within these cells, permanently altering them.
Thus, when one consumes alcohol in such quantities that the body needs to fight to metabolize it, it accumulates in cells, wreaking havoc on DNA . If everything is working properly, a group of enzymes (called aldehyde dehydrogenases -ALDH-) are responsible for neutralizing acetaldehyde turning it into acetate, which the body can use for energy. But, when it accumulates, the problems begin.
“This paper provides very strong evidence that an alcohol metabolite causes DNA damage, important stem cells that become tissues,” explains Ketan Patel, leader of the work.
“We saw a lot of DNA damage in these cells. Pieces of DNA were removed, pieces were broken and we even saw parts of the chromosomes moving and reorganizing,” Patel says.
Previous research found that acetaldehyde causes DNA damage, but these experiments were done in cell cultures, not in a living organism. By using a living being, this mouse study represents a critical advance in understanding what is happening to alcohol within the body.
About 540 million people in Asia, for example, have a mutation in the ALDH2 gene, which means that they cannot process acetaldehyde; hence, when they drink, acetaldehyde builds up causing a flushed complexion and discomfort. People with this mutation have an increased risk of esophageal cancer, according to the researchers.
“Our study highlights that not being able to process alcohol effectively can lead to an even higher risk of alcohol-related harm and therefore certain cancers. But it is important to remember that the alcohol elimination and repair systems DNA is not perfect and alcohol can continue to cause cancer in different ways, even in people whose defense mechanisms are intact, “says Patel.
So far, alcohol consumption has been associated with an increased risk of cancer of the mouth, throat, esophagus, larynx, breast, liver and intestine, and even light consumption, with higher mortality.
Reference: Juan I. Garaycoechea et al, Alcohol and endogenous aldehydes damage chromosomes and mutate stem cells, Nature (2018). DOI: 10.1038 / nature25154
