Maggie's Farm

Based on extensive reviews of research studies, there is a strong scientific consensus of an association between alcohol drinking and several types of cancer (1, 2). In its Report on Carcinogens, the National Toxicology Program of the US Department of Health and Human Services lists consumption of alcoholic beverages as a known human carcinogen. The research evidence indicates that the more alcohol a person drinks—particularly the more alcohol a person drinks regularly over time—the higher his or her risk of developing an alcohol-associated cancer. Based on data from 2009, an estimated 3.5 percent of all cancer deaths in the United States (about 19,500 deaths) were alcohol related (3).

Clear patterns have emerged between alcohol consumption and the development of the following types of cancer:

Head and neck cancer: Alcohol consumption is a major risk factor for certain head and neck cancers, particularly cancers of the oral cavity (excluding the lips), pharynx (throat), and larynx (voice box) (4). People who consume 50 or more grams of alcohol per day (approximately 3.5 or more drinks per day) have at least a two to three times greater risk of developing these cancers than nondrinkers (4). Moreover, the risks of these cancers are substantially higher among persons who consume this amount of alcohol and also use tobacco (5).

Esophageal cancer: Alcohol consumption is a major risk factor for a particular type of esophageal cancer called esophageal squamous cell carcinoma (2). In addition, people who inherit a deficiency in an enzyme that metabolizes alcohol have been found to have substantially increased risks of alcohol-related esophageal squamous cell carcinoma.

Liver cancer: Alcohol consumption is an independent risk factor for, and a primary cause of, liver cancer (hepatocellular carcinoma) (6). (Chronic infection with hepatitis B virus and hepatitis C virus are the other major causes of liver cancer.)

Breast cancer: More than 100 epidemiologic studies have looked at the association between alcohol consumption and the risk of breast cancer in women. These studies have consistently found an increased risk of breast cancer associated with increasing alcohol intake. A meta-analysis of 53 of these studies (which included a total of 58,000 women with breast cancer) showed that women who drank more than 45 grams of alcohol per day (approximately three drinks) had 1.5 times the risk of developing breast cancer as nondrinkers (a modestly increased risk) (7). The risk of breast cancer was higher across all levels of alcohol intake: for every 10 grams of alcohol consumed per day (slightly less than one drink), researchers observed a small (7 percent) increase in the risk of breast cancer.

The Million Women Study in the United Kingdom (which included more than 28,000 women with breast cancer) provided a more recent, and slightly higher, estimate of breast cancer risk at low to moderate levels of alcohol consumption: every 10 grams of alcohol consumed per day was associated with a 12 percent increase in the risk of breast cancer (8).

Colorectal cancer: Alcohol consumption is associated with a modestly increased risk of cancers of the colon and rectum. A meta-analysis of 57 cohort and case-control studies that examined the association between alcohol consumption and colorectal cancer risk showed that people who regularly drank 50 or more grams of alcohol per day (approximately 3.5 drinks) had 1.5 times the risk of developing colorectal cancer as nondrinkers or occasional drinkers (9). For every 10 grams of alcohol consumed per day, there was a small (7 percent) increase in the risk of colorectal cancer.

Research on alcohol consumption and other cancers:

Numerous studies have examined the association between alcohol consumption and the risk of other cancers, including cancers of the pancreas, ovary, prostate, stomach, uterus, and bladder. For these cancers, either no association with alcohol use has been found or the evidence for an association is inconsistent.

However, for two cancers—renal cell (kidney) cancer and non-Hodgkin lymphoma (NHL)—multiple studies have shown that increased alcohol consumption is associated with a decreased risk of cancer (10, 11). A meta-analysis of the NHL studies (which included 18,759 people with NHL) found a 15 percent lower risk of NHL among alcohol drinkers compared with nondrinkers (11). The mechanisms by which alcohol consumption would decrease the risks of either renal cell cancer or NHL are not understood.

How does alcohol increase the risk of cancer?

Researchers have identified multiple ways that alcohol may increase the risk of cancer, including:

metabolizing (breaking down) ethanol in alcoholic drinks to acetaldehyde, which is a toxic chemical and a probable human carcinogen; acetaldehyde can damage both DNA (the genetic material that makes up genes) and proteins
generating reactive oxygen species (chemically reactive molecules that contain oxygen), which can damage DNA, proteins, and lipids (fats) through a process called oxidation
impairing the body’s ability to break down and absorb a variety of nutrients that may be associated with cancer risk, including vitamin A; nutrients in the vitamin B complex, such as folate; vitamin C; vitamin D; vitamin E; and carotenoids
increasing blood levels of estrogen, a sex hormone linked to the risk of breast cancer

Alcoholic beverages may also contain a variety of carcinogenic contaminants that are introduced during fermentation and production, such as nitrosamines, asbestos fibers, phenols, and hydrocarbons.