The link between alcohol and cancer

U.S. Surgeon General Vivek Murthy has issued an advisory calling for updated warnings on alcoholic beverages, cautioning that the consumption of alcohol heightens the risk of several types of cancer.

Labels currently on alcoholic beverages warn about drinking while pregnant, drinking while driving and operating other machinery, and other general “health risks.” Murthy noted that alcohol consumption contributes to approximately 100,000 cancer cases and 20,000 cancer-related deaths each year.

Dr. Vasilis Vasiliou, PhD, chair of the Department of Environmental Health Sciences and the Susan Dwight Bliss Professor of Epidemiology at the Yale School of Public Health, is a leading expert in the field of alcohol research, with over 250 published papers in the areas of alcohol metabolism, toxicity, and environmental toxicology, and three edited books on alcohol and cancer. Dr. Vasiliou organized the 2^nd, 3^rd, and 4^th international conferences on alcohol and cancer and is now preparing for the 5^th conference, scheduled for May in Greece. Dr. Vasiliou recently took a moment out of his busy schedule to discuss issues surrounding the Surgeon General’s warning.

Vasilis Vasiliou: To address this question, we first need to evaluate whether ethanol itself causes cancer. Ethanol, also known as grain alcohol or ethyl alcohol, is the alcohol found in alcoholic beverages. It is created during the fermentation process of carbohydrates with yeast. Epidemiological studies have suggested that alcohol consumption is associated with an increased incidence of cancer. However, a direct causal relationship has not been established, except in cases of chronic alcohol abuse leading to liver cancer. In animal studies, alcohol alone does not appear to induce cancer. However, when alcohol is consumed in combination with known carcinogens, such as diethyl nitrosamine, it may contribute to cancer development. Diethyl nitrosamine (DEN) is a chemical carcinogen found in tobacco smoke, cured and fried foods, cheddar cheese, agricultural chemicals, pharmaceuticals, cosmetics, and other products.

Alcohol has been classified as a carcinogen primarily due to its metabolite, acetaldehyde, which has the ability to bind to DNA and potentially cause mutations. Additionally, the metabolism of alcohol by the enzyme cytochrome P450 2E1 (CYP2E1) can generate reactive oxygen species (ROS), leading to oxidative stress. It is important to note that ethanol metabolism by CYP2E1 typically occurs only at high levels of alcohol in the body, such as those seen in individuals with alcohol use disorder. Oxidative stress is a key factor in cancer development as it can cause an imbalance between the production of ROS and the body’s antioxidant defense system. ROS can damage DNA, proteins, and lipids, which can lead to cancer.

Acetaldehyde may also increase the risk of aerodigestive cancers, which include cancer of the lip, tongue, salivary glands, and other oral and nasal regions. Furthermore, acetaldehyde may have a more pronounced effect on individuals with mutations in DNA-repair enzymes, such as BRCA1 and BRCA2. Mutations in these BRCA1 and BRCA2 enzymes can increase the risk of developing breast or ovarian cancer.

Last, but not least, it is crucial to recognize that the adverse effects of alcohol are significantly influenced by the dose-response relationship, which considers both the quantity of alcohol consumed daily and the duration of consumption over time. These factors, along with co-exposures to environmental contaminants, play a pivotal role in determining the severity of alcohol-related risks. Such interactions suggest that alcohol's harmful effects cannot be fully understood in isolation but should instead be evaluated within the broader context of combined exposures to other environmental and lifestyle-related carcinogens. As I stated during the 4^th International Conference on Alcohol and Cancer, "We need to start looking at alcohol in the context of the exposome—a measure of all the exposures a person has throughout their lifetime and their interactions."

VV: I’m addressing this question based on a recent publication by the National Academies of Sciences, Engineering, and Medicine (NASEM) titled “Review of Evidence on Alcohol and Health” (2025).

Evidence on Moderate Alcohol Consumption and Health:

• Cardiovascular Health: Some studies have linked moderate alcohol consumption (up to 1 drink per day for women and 2 drinks per day for men) to a lower risk of certain cardiovascular events, such as myocardial infarction (heart attack) and ischemic stroke. Red wine, in particular, has been noted for its potential benefits due to antioxidants like resveratrol. However, the NASEM report emphasizes that these benefits are not unique to alcohol. They can also be derived from non-alcoholic sources of antioxidants, such as grapes and other fruits. Importantly, the evidence supporting a protective effect of moderate alcohol consumption on cardiovascular health is of low to moderate certainty, largely due to confounding factors and limitations in observational study designs.
• All-Cause Mortality: Moderate alcohol consumption is associated with a lower risk of all-cause mortality in some analyses. However, this association is complicated by "abstainer bias", as many studies fail to differentiate between lifelong abstainers and former drinkers who may have stopped due to health issues.
• Neurocognition: Evidence on the effects of moderate alcohol consumption on neurocognitive outcomes, such as dementia or Alzheimer’s disease, remains inconsistent. The NASEM report concludes that there is insufficient evidence to draw firm conclusions.

Advice on Alcohol Consumption in Light of Emerging Findings:

• Do Not Start Drinking for Health Reasons: The NASEM report, aligned with dietary guidelines, advises against starting to drink alcohol for perceived health benefits. Safer and more effective alternatives exist, such as a balanced diet rich in fruits, vegetables, and whole grains.
• Limit Consumption: For those who choose to drink, moderation is key—up to 1 drink per day for women and 2 drinks per day for men. Even at moderate levels, alcohol consumption carries risks, particularly for certain cancers.
• Consider Personal and Family Health Risks: Individuals with a family history of alcohol use disorders, breast cancer, or other alcohol-related diseases should exercise caution.
• Seek Non-Alcoholic Sources of Antioxidants: The benefits attributed to red wine, such as from resveratrol, can also be obtained from non-alcoholic sources like grapes, berries, and nuts.

VV: The NASEM report confirms that even moderate alcohol consumption is associated with an increased risk of certain cancers, such as breast and colorectal cancer. For example, moderate drinking has been linked to a 10% increased risk of breast cancer compared to non-drinkers. Women are particularly vulnerable to alcohol-related cancers due to hormonal and metabolic factors.

However, it is important to consider the role of other environmental carcinogens in contributing to this risk.

Interaction with Other Carcinogens:

• Alcohol consumption can amplify the carcinogenic effects of other environmental exposures, such as cigarette smoking and air pollutants. For instance, the combination of alcohol and smoking greatly increases the risk of cancers in the oral cavity, throat, and esophagus.
• Other environmental factors, such as pesticides, endocrine disruptors, and occupational carcinogens, may interact with alcohol to exacerbate its effects on breast tissue and other organs, potentially contributing to the observed increased cancer risk.

In conclusion, women are at a heightened risk of alcohol-related cancers, particularly breast cancer. However, this risk is influenced by synergistic interactions with other environmental carcinogens and lifestyle factors. Reducing alcohol intake, alongside minimizing exposure to other known carcinogens such as tobacco smoke, environmental pollutants, and chemical toxins, is a critical strategy for lowering overall cancer risk. Comprehensive prevention efforts should address not only alcohol consumption but also broader environmental and lifestyle factors.