How alcohol damages DNA & Risk of cancer

Maybe I need to re-think that second glass of red wine. Some researchers in England have now conducted a study in mice to study how alcohol damages our DNA and can increase the risk of cancer. Experts say the mechanisms linking alcohol to DNA damage are the same in mice and men, and earlier studies have shown strong links between alcohol and certain cancers in humans. The International Agency for Cancer Research classes alcohol consumption as carcinogenic to humans. But how did alcohol do the damage?

A study was published in the journal Nature that took a look at how exposure to alcohol and compounds that result when the body breaks down alcohol, causes damage to chromosomes in the blood stem cells. The cells are crucial for replenishing those cells lost throughout the life span and once damaged, they can spread the damage even further. Stem cells can divide and replenish cells for long periods of time.

Researchers gave mice doses of alcohol equivalent to an adult human drinking one bottle of whiskey in a short period of time. Some mice were genetically engineered to remove two crucial mechanisms protecting against the harmful side effects of alcohol metabolism, leaving these mice vulnerable. Lead study author Dr. KJ Patel, a tenured principal investigator at MRC Laboratory of Molecular Biology in Cambridge, England said that when alcohol is processed by the body it converts into the highly reactive toxin acetaldehyde that damages DNA.

There are two mechanisms that protect the cell from acetaldehyde. There is an enzyme that detoxifies and removes the acetaldehyde and a second mechanism that springs into action after the damage is done and is comprised of DNA repair systems that fix the damage as it occurs.

Experiments were conducted with 3 groups of mice. A group of mice with both protection mechanisms in place and mice that didn’t have the acetaldehyde-removing enzyme called aldehyde dehydrogenase 2, but did have the DNA repair mechanisms. There were also mice with neither the enzyme nor the DNA repair mechanisms.

By removing the first level of protection, just giving the mice one big dose of alcohol is enough to initiate 4X more DNA damage than in normal mice. Many people either lack this protective enzyme or have an impaired function of it and is a condition especially common in Asia, where about 5 million people are affected. The second layer of protection or the DNA repair mechanisms also commonly have problems.

In the study, they focused on DNA damage in blood stem cells, where previous research has shown alcohol affects blood cells, and many with alcoholism become anemic, which means too few red blood cells. It is believed that most cancers arise from stem cells.

Our organs and tissues have stem cells, immortal cells that replenish cells lost throughout our lives and the hematopoietic system. This is how blood cells are generated in the body.

The new Cambridge study found that mouse hematopoietic stem cells can be mutated by a metabolite of alcohol, acetaldehyde. Alcohol is believed to contribute to at least 7 types of cancer. It seems it would be good to slow down our consumption of alcohol.

Dr Fredda Branyon