Those abstaining from alcohol this month now have extra reason to be smug as a new study, published today in Nature sheds light on how alcohol damages DNA and increases the risk of cancer.
Scientists and doctors have previously linked alcohol to an increased risk of developing at least seven types of cancer, and attribute it to causing almost 20,000 cancer deaths in the USA per year, but until now, the exact way in which alcohol damages DNA has not been clear.
Scientists at the MRC Laboratory of Molecular Biology in the UK gave ethanol, the type of alcohol found in alcoholic beverages, to mice and then looked at their DNA to see what genetic damage had been sustained. They found that acetaldehyde, a breakdown product of ethanol, damaged the DNA within blood stem cells, leaving them riddled with mutations that could lead to cancer.
Professor Ketan Patel, the lead author of the study, said: “Some cancers develop due to DNA damage in stem cells. While some damage occurs by chance, our findings suggest that drinking alcohol can increase the risk of this damage.”
The study also investigated how the body breaks down alcohol and how this contributes to the risk of DNA damage after indulging. Aldehyde dehydrogenases (ALDH) are a group of enzymes which break down acetaldehyde into benign acetate, which can actually be used as a source of energy for cells and hence is a large part of the unfortunate calorie-burden of alcohol.
Worldwide, over half a billion people lack or have mutations in ALDH genes, meaning that after drinking, they get a build up of acetaldehyde, which also gives them a flushed complexion and can mean they feel unwell. People most likely to have these mutations are often of South East Asian heritage, including millions of Americans, but the deficiency can occur in people of any ethnicity.
The researchers gave ethanol to mice lacking ALDH2, the most important ALDH enzyme, and found that these mice had four times as much DNA damage in their cells when compared to mice who had the fully-functioning ALDH2 enzyme. This research adds to work that has previously suggested that people with ALDH2 deficiency were at greater risk of developing esophageal cancer after drinking.
The American Cancer Society recommends a maximum of one drink a day for women and two for men. However, this new study adds to a wave of recent expert opinion and evidence which suggests that there is no ‘safe limit’ for alcohol consumption and even minimal drinking will cause some level of DNA damage.