Alcohol Consumption and Cancer Link, Explained

April is Alcohol Awareness Month and since 1995, alcohol consumption has been on the rise. During the pandemic, however, alcohol consumption has increased to a greater degree due to stress related to COVID-19, boredom and easy access to alcohol at home while isolating during the pandemic.

Alcoholic beverages of all types – beer, wine, liquor – increase the risk of developing cancer.  One type of alcohol is not “safer” than another because they all contain the same ingredient: ethanol. The amount of alcohol consumed is the important factor.
 

Risk Increases with Greater Intake

After about one drink per day for women and two drinks per day for men, risk of cancer increases. Heavy drinkers are at the greatest risk. Heavy drinking is considered more than 15 drinks per week for men and more than 8 drinks per week for women. As expected, the earlier in life alcohol use begins the greater the risk of developing cancer.

Alcohol and Cancer

Alcohol significantly impacts the upper portion of the digestive tract because it is an irritant, and it has direct contact with tissues in the mouth and throat. The AICR/WCRF Third Expert Report concluded there is strong evidence that consuming alcoholic beverages increases the risk of cancers of the mouth, pharynx, larynx and esophagus.

The lower digestive tract is also impacted by alcohol consumption.

• Two or more alcoholic beverages a day increases the risk of colorectal cancer.

• Three or more alcoholic beverages a day increases the risk of stomach and liver cancers.

• There is limited but suggestive evidence that alcoholic beverages increase the risk of lung, pancreatic and skin cancer.

In addition to cancers of the digestive tract, alcohol increases risk of pre and postmenopausal breast cancer.

Alcohol Damages DNA

There are several likely ways in which alcohol increases cancer risk, although the mechanisms are not fully understood. It is known that alcohol causes DNA damage. DNA is a complex molecule that contains the information that a cell needs to make it work properly and regrow.  The ethanol in alcohol is broken down by our body to acetaldehyde, which is toxic and believed to be the link towards damaging cellular DNA.

Secondly, alcohol creates oxidative stress resulting in changes, errors and breaks in DNA. If the DNA gets repeatedly damaged, it can begin to function or replicate incorrectly. Over time, the cell is unable to repair itself and cancer forms.

Ethanol is also a solvent, meaning it can help other cancer-causing substances, like carcinogens from tobacco, enter cells and cause damage. This may be one of the reasons why those who drink alcohol and use tobacco are at the greatest risk of developing cancers in the mouth and throat.

Alcohol and Diet

Alcohol consumption can have a significant impact on a person’s nutritional status. Alcohol is a significant source of calories on its own and it is frequently added to high calorie, sugar-sweetened beverages like juice, soda, simple syrups and milk or cream. Excess calorie intake can contribute to obesity, which is a major risk factor for developing cancer. Heavy drinkers are more likely to experience weight gain than those who drink less.

Heavy drinkers are also often at risk for malnutrition, as they may choose to drink instead of eat. Calories from beverages containing alcohol can displace nutrients from healthy foods.

The body does not use or store alcohol, so the liver prioritizes the metabolism of alcohol over the metabolism of food. Alcohol metabolism can interfere with the metabolism of many nutrients including folate, an important nutrient for making DNA.

Alcohol Intake and Cancer Survivors

For those going through cancer treatment, alcohol consumption can negatively impact side effects that are experienced. Mouth sores, inflammation to the inside of the mouth, painful swallowing and diarrhea can all be exacerbated by drinking alcohol. Alcoholic beverages may replace healthy foods and interfere with nutrient intake, absorption and adequate calories needed for healing.

For those who have completed treatment, it is best to talk with your healthcare team about consuming alcohol. Studies are not clear if alcohol intake causes cancer recurrence, but alcohol consumption increases risk for a secondary cancer and other chronic disease like liver disease and obesity.

How to Drink Less Alcohol

• AICR recommends, for cancer prevention and cancer survivors, it is best not to drink alcohol. For those who do choose to drink alcohol, it is recommended to follow national guidelines. The 2020-2025 Dietary Guidelines for Americans recommendation is “for those who choose to drink, intakes should be limited to 1 drink or less in a day for women and 2 drinks or less in a day for men, on days when alcohol is consumed.”

• Do not use alcohol as a stress reducer. Instead engage in exercise, community groups, or a new hobby.

• Make non-alcoholic beverages or reduced-alcohol choices that include a splash of alcohol.

 

Resources

• Cancer Trends Progress Report. National Cancer Institute, March 2020, https://progressreport.cancer.gov/prevention/alcohol. Accessed March 2021.

• Grossman ER, Benjamin-Neelon SE, Sonnenschein S. Alcohol Consumption during the COVID-19 Pandemic: A Cross-Sectional Survey of US Adults. Int J Environ Res Public Health. 2020;17(24):9189.

• Alcohol and Public Health. Centers for Disease Control and Prevention, Feb. 2021. https://www.cdc.gov/alcohol/faqs.htm#heavyDrinking Accessed March 2021.

• World Cancer Research Fund/American Institute for Cancer Research. Continuous Update Project Expert Report 2018. Alcoholic drinks and the risk of cancer. Available at dietandcancerreport.org Accessed March 2021

• Traversy G, Chaput J. Alcohol Consumption and Obesity: An Update. Curr Obes Rep. 2015;4(1):122-130.