Since 1987, when the International Agency for Research on Cancer first classified alcohol as a human carcinogen, the connection between alcohol consumption and cancer risk has been well established. Research from both human and animal studies continues to show a rising cancer risk alongside increased alcohol consumption. Here’s what current research says about alcohol and its cancer risks:
What Do Dietary Guidelines Say About Alcohol Consumption?
The U.S. dietary guidelines recommend a limit of two or fewer drinks per day for men and one drink or fewer per day for women. However, risks for certain cancers, such as breast, mouth, and throat cancers, may begin to increase even with just one or fewer drinks per day, according to the Surgeon General’s report.
Which Cancers Are Linked to Alcohol Consumption?
Alcohol consumption has been shown to increase the risk of several types of cancer, with the strongest evidence for the following:
- Breast
- Colon and rectum
- Esophagus
- Liver
- Mouth
- Throat
- Larynx
How Does Alcohol Cause Cancer?
The Surgeon General’s report highlights four key mechanisms by which alcohol increases cancer risk:
- DNA Damage: Alcohol is metabolized into acetaldehyde, a substance that can damage DNA and impair the body’s ability to repair it, leading to mutations and uncontrolled cell growth.
- Oxidation and Inflammation: Acetaldehyde is converted into acetate, producing unstable molecules that damage cells and contribute to cancer-causing inflammation.
- Raising Tobacco Risks: Alcohol can dissolve carcinogens from tobacco smoke, making it easier for them to enter the body and increase cancer risk.
- Hormone Production: Alcohol increases hormone levels, particularly estrogen, which heightens the risk of breast and ovarian cancers.
Why Are Some Organs at Higher Risk for Alcohol-Related Cancers?
Alcohol affects various organs differently:
- Breast Cancer: Increased hormone levels, particularly estrogen, elevate the risk for breast cancer.
- Mouth and Esophagus: Alcohol irritates and damages the mucosal lining, increasing susceptibility to carcinogens, including tobacco.
- Liver: The liver processes alcohol, resulting in high acetaldehyde concentrations. Chronic alcohol use can lead to cirrhosis, a major risk factor for liver cancer.
- Pancreas: Chronic alcohol-induced inflammation increases the risk of pancreatic cancer.
Does Quantity of Alcohol Consumption Affect Cancer Risk?
Cancer risk increases with higher levels of alcohol consumption. The Surgeon General’s report estimates that approximately 10 out of every 100 men who consume less than one drink per week will develop an alcohol-related cancer, while 11 out of every 100 who drink one daily drink, and 13 out of every 100 who consume two drinks per day, will develop one. For women, higher alcohol consumption raises the risk for breast cancer, with about 11 cases in every 100 for those who consume less than one drink per week, 13 cases for one drink daily, and 15 cases for two drinks daily.
Are Shifting Patterns of Alcohol Use Affecting Cancer Rates?
Increases in alcohol consumption, especially among women, have contributed to rising alcohol-related cancer cases, as suggested in a 2021 The Lancet Oncology report.
What Are the Limits of What We Know?
While acetaldehyde and inflammation are well understood in terms of their role in cancer risk, the effects of alcohol as a solvent and its role in hormone regulation require further research. Additionally, individual cancer risk is shaped by a complex interplay of genetic, environmental, and social factors.
Are There Any Health Benefits of Alcohol?
While moderate alcohol consumption is linked to a lower risk of death from certain causes, a January 2025 report from the U.S. National Academies of Sciences, Engineering, and Medicine also found connections between alcohol and cancer. However, moderate alcohol intake may also reduce risks for nonfatal heart attacks, strokes, and deaths from heart disease.
Defining One Drink
The U.S. Centers for Disease Control and Prevention defines one alcoholic drink as:
- 1.5 ounces of 80-proof liquor
- 5 ounces of wine with 12% alcohol
- 12 ounces of beer with 5% alcohol
Understanding the risks of alcohol consumption and its connection to cancer is crucial for making informed health decisions.
