Alcohol is the third leading preventable cause of cancer in the United States, after tobacco and obesity—but few people know this.
In a January 3 advisory, acting U.S. surgeon general, Dr. Vivek Murthy, cited data that showed that nearly 90 percent of U.S. adults know that tobacco use increases the risk of cancer, but only 45 percent are aware of the cancer risk from alcohol consumption.
Murthy’s advisory outlined a vast amount of research linking alcohol—which is a toxin—with an increased risk of cancer and recommended adding health warning labels to alcoholic drinks.
“This isn’t a case where something might cause cancer: This is a case where something, in numerous trials, has been concluded [that it] does cause cancer,” Dr. Otis Brawley, an oncologist, epidemiologist, and professor at Johns Hopkins University School of Medicine, tells PGN. “All I want is for people who are drinking a beer, or wine, or a glass of whiskey [to] realize that they are taking a risk.”
Read on for more information about how alcohol can cause cancer and who’s most at risk.
Research shows that alcohol causes at least seven types of cancer
Murthy’s report detailed various studies from the last two decades that show that drinking alcohol increases the risk of developing at least seven types of cancer: mouth, throat, esophageal, laryngeal, breast, liver, and colon.
Breast cancer is the most common cancer caused by alcohol consumption. In 2019, alcohol consumption caused 16.4 percent of breast cancer cases in the U.S., according to Murthy’s report.
How does alcohol cause cancer?
There are several mechanisms in which alcohol can cause cancer.
“The liver is the organ that takes care of detoxifying the body, so any toxins, including alcohol, need to go through the liver,” explains Dr. Juan Pablo Arab Verdugo, director of alcohol sciences at the Stravitz-Sanyal Institute for Liver Disease and Metabolic Health, part of the Virginia Commonwealth University School of Medicine, and liver specialist at VCU Health. “The liver tries to metabolize the alcohol, but in that process, the liver gets damaged, so there is inflammation in the liver, and then [it] tries to regenerate itself, and that generates [a] scarring process.”
Additionally, the liver breaks alcohol down into acetaldehyde, a toxic chemical that can affect the DNA (genetic material), adds Brawley. If this damage happens, it can affect the part of the genes that keep cells from dividing, which can cause cancer.
“Cancer is uncontrolled cell growth,” Brawley says. “It’s one cell becoming two, becoming four, becoming eight, becoming 16, without the ability of the genetics to stop, and if you have damage to the part of genes that stops the cell from dividing, you have a cancer.”
In the case of breast cancer, alcohol can raise levels of estrogen, a female sex hormone that helps with the growth of breast tissue.
Women who drink have a higher risk of certain alcohol-related problems than men
Research also shows that women who drink alcohol have a higher risk than men of developing certain alcohol-related problems, including cancer, largely due to the way women process alcohol in their bodies.
Women have a lower concentration of alcohol dehydrogenase (ADH), an enzyme that breaks down alcohol in the body. More alcohol makes it into women’s small intestine for further absorption compared to men’s, which increases the concentration of alcohol in women’s blood.
Additionally, because men have a higher ratio of muscle to fat compared to women, alcohol is more diluted in men’s bodies because they have a larger amount of blood, explains Dr. Ravi Mehrotra, a cancer researcher, professor at Emory University, and member of WHO’s International Agency for Research on Cancer.
Women also have less water in their bodies than men, which means that “alcohol levels tend to get higher,” Mehrotra adds.
There’s no safe amount of alcohol, but your risk depends on how much you drink
In the early 1990s, some studies found that drinking red wine might reduce the risk of heart disease, but more recent research concluded the opposite. And in 2022, WHO published a statement confirming that no amount of alcohol is safe.
“Now we know that there is no benefit of alcohol,” Arab Verdugo says. “It has been proven that even a small amount is bad, not only for the liver, but now there is also very strong data showing increased cardiovascular mortality, so [an] increased risk of having heart failure, a stroke, arrhythmias, and also cancer.”
The former surgeon general’s report detailed that the risk of cancer increases the more someone drinks. For some cancers—like breast and throat cancers—the risk starts to increase at one or fewer drinks per day. The risks for alcohol-derived cancer can also increase based on other factors.
“The risk of having liver cancer if you are overweight and you are drinking heavily is eight times more than someone that only has one of the risk factors,” Arab Verdugo adds. “It really works in combination with other factors.”
Overall, he says, people should be mindful of their own risk factors, including diabetes, obesity, liver disease, and hepatitis B or C.
According to the current Dietary Guidelines for Americans, alcohol consumption should be limited to two drinks or fewer per day for men and one drink or fewer per day for women.
“We’re not necessarily telling people to stop drinking, but we don’t want people to be making a conscious decision to put their life at risk,” Brawley concludes. “[We want to] make it a conscious decision: You know there’s a risk, you’ve decided to take this risk.”
For more information about how alcohol affects your health, visit the National Institute of Health’s website Rethinking Drinking.