EXPLAINER: How alcohol consumption impacts cancer risk

The United States Surgeon General on Friday, January 3, said all alcoholic drinks, whether beer, wine or spirits, should carry a label warning that consumption increases the risk of cancer.

A link between alcohol use and cancer has been recognized at least since 1987, when the International Agency for Research on Cancer first classified alcohol as a carcinogen to humans.

Evidence for this link from studies in humans and animals has strengthened since then, according to the Surgeon General’s report, which shows risks rising modestly along with consumption. Here is what research has shown about alcohol intake and cancer:

What do dietary guidelines say about alcohol consumption?

US dietary guidelines currently recommend two or fewer drinks per day for men and one drink or less per day for women. For certain cancers, like breast, mouth, and throat cancers, risks may start to increase around one or fewer drinks per day, the report says.

Which cancers have been linked with alcohol consumption?

The evidence that alcohol consumption increases the risk of malignancy is strongest for cancers of the breast, colon and rectum, esophagus, liver, mouth, throat, and larynx.

How does alcohol cause cancer?

The Surgeon General’s report highlights four ways in which alcohol consumption raises cancer risks.

• DNA damage: The body processes alcohol into acetaldehyde, a chemical compound that can damage DNA and prevent cells from repairing the damage, increasing the likelihood of mutations and uncontrolled cell growth that contributes to tumor formation.
• Oxidation and inflammation: Acetaldehyde is in turn converted into acetate in a process that involves oxidation, producing dangerous unstable oxygen-containing molecules that damage cells and contribute to cancer-causing inflammation.
• Raising risk from tobacco: Carcinogens from other sources, especially particles of tobacco smoke, can dissolve in alcohol, making it easier for them to be absorbed into the body.
• Hormone production: Alcohol consumption increases levels of hormones, including estrogen, which can increase risks for breast and ovarian cancers.

Why are some organs at higher risk of alcohol-related cancers?

The hormone-related risk for breast cancer is highlighted in the report. In addition, in the mouth and esophagus, and throughout the gastrointestinal tract, alcohol irritates and damages the protective mucosal lining that normally protects cells from carcinogens, including tobacco.

The liver processes alcohol, leading to high acetaldehyde concentrations. Chronic alcohol-induced inflammation can also lead to cirrhosis, a major risk factor for liver cancer.

Alcohol-induced inflammation can also increase the risk of pancreas cancer.

Does quantity of alcohol consumption affect cancer risk?

The risk of cancer increases with the level of alcohol consumption. The Surgeon General’s report estimates that an alcohol-related cancer will develop in about 10 of every 100 men who consume less than one drink per week, 11 of every 100 who average one drink daily, and in 13 of every 100 who consume two drinks daily.

Higher alcohol consumption increases breast cancer risk in women from roughly 11 cases in every 100 of those who consume less than one drink per week, to 13 cases in every 100 who consume one drink per day and 15 in every 100 who consume two drinks per day, according to the report.

Are shifting patterns of alcohol use affecting cancer rates?

Global changes in alcohol drinking patterns by region and sex — including increases in alcohol consumption by women — might account for an increase in alcohol-attributable cancer cases, a 2021 report in The Lancet Oncology suggested.

What are the limits of what we know?

The evidence is strongest for the roles of acetaldehyde and inflammation in raising cancer risks, the report notes, while hormone regulation and alcohol as a solvent are not yet fully understood.

Each person’s risk for developing cancer, including alcohol-related cancers, is determined by a complex interaction of biological, environmental and social factors.

Are there any health benefits of alcohol?

A January 2025 report from the US National Academies of Sciences, Engineering, and Medicine concludes that moderate alcohol consumption is associated with a lower rate of deaths from any cause compared with no consumption. While it did find links between alcohol and cancer, it also found evidence to suggest that consuming moderate amounts of alcohol is associated with lower risks for nonfatal heart attacks, nonfatal strokes, and deaths from heart disease.

*The US Centers for Disease Control and Prevention defines one alcoholic beverage as 1.5 ounces of 80-proof liquor, 5 ounces of wine with 12% alcohol, or 12 ounces of beer with 5% alcohol. – Rappler.com