Drinking alcohol doesn't just damage the liver and kidneys — turns out it could increase cancer risks and damage DNA as well.
A new study that helps to explain the link between drinking and cancer claims that alcohol consumption can cause permanent genetic damage to the body's stem cells. The researchers gave ethanol to genetically modified mice and found that alcohol causes cancer by scrambling DNA in cells.
Why Drinking Might Lead To Cancer
"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," according to Ketan Patel, the study's lead author.
In the study, published Jan. 3 in the Nature journal, the researchers gave mice diluted alcohol then observed how it affected their DNA. They discovered that acetaldehyde, a toxic chemical produced when the body processes alcohol, can destroy DNA within blood stem cells, causing permanent changes to its sequences.
The Body's Defense Mechanisms
According to Patel, discovering that behavior is crucial because stem cell damage can lead to cancer. However, it's important to note that the effects of acetaldehyde can be neutralized by two of the body's natural defense mechanisms: the first one fights acetaldehyde and the second one repairs DNA damage.
But when these two layers of defense were genetically thrown out, DNA damage was able to accumulate to a point where it caused cells to stop working entirely.
On mice, the damage worsens if they lack the first layer of defense, a protective enzyme called aldehyde dehydrogenase 2, or ALDH2, whose job is to prevent toxic acetaldehyde buildup.
The researchers gave ethanol to mice lacking ALDH2, and discovered that these mice had four times as much damage in their DNA cells when compared with mice that had the enzyme. The research supports previous studies suggesting that people deficient in ALDH2 are more likely to develop esophageal cancers.
Not having the two defense mechanisms increases one's risks of developing cancer and damaging their DNA through alcohol consumption. However, this defense system isn't airtight, said Patel.
"[I]t's important to remember that alcohol clearance and DNA repair systems are not perfect and alcohol can still cause cancer in different ways, even in people whose defence mechanisms are intact."
Doctors have previously linked alcohol consumption to an increase risk of developing seven types of cancer, but until now, exactly how alcohol causes DNA damage hasn't been really clear.
Currently, the American Cancer Society recommends just one drink of alcohol for women and two for men, but the study proves there's no safe limit for alcohol consumption. Even minimal drinking might cause some level of DNA damage.