We've heard it before, but the recent release of our new Guideline for Diet and Physical Activity for Cancer Prevention, underscores the hard reality: you'll be healthier if you abstain from alcohol.
Alcohol use is one of the most important preventable risk factors for cancer, along with tobacco use and excess body weight. Alcohol use accounts for about 6% of all cancers and 4% of all cancer deaths in the U.S.
The more alcohol you drink, the higher your cancer risk. But for some types of cancer, most notably breast cancer, consuming even small amounts of alcohol can increase risk. Alcohol can raise estrogen levels in the body.
Drinking and smoking together raises the risk of these cancers many times more than drinking or smoking alone. This might be because alcohol can help harmful chemicals in tobacco get inside the cells that line the mouth, throat, and esophagus. Alcohol may also limit how these cells can repair damage to their DNA caused by the chemicals in tobacco.
Ethanol is the type of alcohol found in alcoholic drinks, and most evidence suggests that it is the ethanol that increases the risk, not other things in the drink. Alcoholic drinks contain different percentages of ethanol, but in general, a standard size drink of any type — 12 ounces of beer, 5 ounces of wine, or 1.5 ounces of 80-proof liquor — contains about the same amount of ethanol (about half an ounce). Of course, larger or ‘stronger’ drinks can contain more ethanol than this.
Overall, the amount of alcohol someone drinks over time, not the type of alcoholic beverage, seems to be the most important factor in raising cancer risk.
Once in the body, alcohol can be converted into acetaldehyde, a chemical that can damage the DNA inside cells and has been shown to cause cancer in lab animals.
Drinking alcohol can also lead to oxidative stress in cells, causing them to create more reactive oxygen species (chemically reactive molecules that contain oxygen). These can lead to damage inside the cells that might increase the risk of cancer.
Alcohol and its byproducts can also damage the liver, leading to inflammation and scarring (cirrhosis). As liver cells try to repair the damage, they can end up with mistakes in their DNA, which could lead to cancer.
Alcohol might also affect the body’s ability to absorb some nutrients, such as folate. Folate is a vitamin that cells in the body need to stay healthy. Absorption of nutrients can be even worse in heavy drinkers, who often consume low levels of folate to begin with. Low folate levels may play a role in the risk of some cancers, such as breast and colorectal cancer.
What does the American Cancer Society recommend?
Simply, our new guideline says it is best not to drink alcohol. People who choose to drink alcohol should limit their intake to no more than 2 drinks per day for men and 1 drink a day for women.
The recommended limit is lower for women because of their smaller body size and because their bodies tend to break down alcohol more slowly.
In 2016, approximately 50.7% of the U.S. population aged age 12 and over reported having consumed alcohol in the past 30 days.
For both men and women, the prevalence of alcohol abstinence is higher among Hispanics, African Americans, Asians, and Native Americans than among non-Hispanic whites. Among current drinkers, the prevalence of heavy weekly drinking is highest among Native Americans, and the prevalence of heavy daily drinking is highest among Hispanic men.
How much damage does alcohol actually do?
It was recently estimated that in 2014, alcoholic beverage consumption caused 5.6% of all incident cancer cases and 4% of all cancer deaths among males and females in the U.S., an estimated:
- 40.9% of oral cavity/pharynx cancers
- 23.2% of larynx cancers
- 21.6% of liver cancers
- 21% of esophageal cancers
- 12.8% of colorectal cancers
- 16.4% of all breast cancers among women
Sadly, our new guideline notes that public knowledge of the link between alcohol and cancer is low.