Connections to Cancer: How Alcohol Consumption Damages DNA and Increases Risk of Cancer
Posted on January 25, 2018
Alcohol can cause more than a hangover – it can also lead to an increased risk of developing some types of cancer.
Researchers at the MRC Laboratory of Molecular Biology in Cambridge, England, clarified the connection between alcohol, stem cells and cancer in a recent study.
In the U.K., alcohol contributes to over 12,000 cancer diagnoses each year.
The study shows that consuming alcohol increases the risk of developing cancer by affecting DNA. Specifically, the research shows that alcohol scrambles DNA in blood stem cells and cause irreversible damage, which can lead to changes in chromosomes over time that result in cancer.
“Stem cells are the most basic building blocks of the body and develop into blood cells, tissues and organs. When they become damaged, they cannot replace old cells or cells that are lost due to injury, illness or aging,” said Dr. Joel Singer, a New York stem cell physician.
The study suggests that consuming even a pint of beer or a glass of wine per day raises the risk of developing several types of cancer, including mouth, throat and esophageal cancer.
Breast and bowel cancers also increase because of alcohol consumption.
The study authors used genetically altered mice to connect alcohol consumption to cancer. The study expands previous research that showed acetaldehyde, a byproduct created during the breakdown of alcohol, as a toxin that causes damage to DNA.
The difference between previous studies and the MRC Laboratory study is that earlier studies used high amounts of acetaldehyde on cells in a petri dish, rather than observing the effects of acetaldehyde on the body.
The MRC Laboratory study illustrated how acetaldehyde damages DNA by cutting through it, leaving the genes damaged.
Researchers found that the body has two natural defense systems against acetaldehyde. First, the body tries to mitigate damage by breaking down the acetaldehyde using enzymes called aldehyde dehydrogenases, or ALDHs. The ALDHs turn acetaldehyde into acetate to use for energy.
In the second defense system, the body works to repair the blood stem cells with damaged DNA.
The researchers illustrated how acetaldehyde could affect the body by giving alcohol to mice that lacked a specific type of ALDH enzyme known as ALDH2.
Results of the test found that the DNA of the mice experienced four times greater damage than mice that had working ALDH2.
Without a functioning ALDH2 enzyme, the body can build up dangerous levels of acetaldehyde. Around 8 percent of the global population has a malfunctioning ALDH2 enzyme.
The MRC Laboratory study focused on blood stem cells because, unlike other stem cells, blood stem cells are continually in use by the body to provide fresh blood. Blood stem cells also multiply very quickly, which allowed the researchers to sequence the cells efficiently to track changes in their DNA.
The mice that had malfunctioning ALDH2 enzymes to protect against acetaldehyde buildup and subsequently defend themselves against DNA damage lost their ability to restore their blood supply entirely after given alcohol for 10 days.
Researchers sequenced the DNA of these mice and found that the cells were no longer able to function at all.
The summary of the study shows that the inability to process alcohol can increase the risk of alcohol-related damage to the DNA and lead to some forms of cancer.
Approximately 8 percent of the global population cannot break down acetaldehyde into acetate. Many of those who cannot process alcohol are of Eastern Asian descent, which could attribute to high rates of esophageal cancer in countries such as China.
The study authors also noted that although some individuals are able to process alcohol, it does not mean that this process and the process to repair damage are enough to protect against cancer.
Although alcohol consumption has links to the development of breast, bowel, throat and esophageal cancers, previous research has not connected drinking alcohol to higher rates of blood cancer.
Reuters. How alcohol damages stem cell DNA and increases cancer risk. Reuters. 3 January 2018.