FACT SHEETS

Alcohol and Risk

What is ? consume. However, they may not reflect consumption of alcoholic beverages Alcohol is the common term for etha- the typical serving sizes people may as a known human carcinogen. nol or ethyl alcohol, a chemical sub- encounter in daily life. The evidence indicates that the more stance found in alcoholic beverages such According to the federal government’s alcohol a person drinks—particu- as beer, hard cider, malt liquor, wines, Dietary Guidelines for Americans 2015- larly the more alcohol a person drinks and distilled spirits (liquor). Alcohol is 2020, individuals who do not drink regularly over time—the higher his produced by the fermentation of sugars alcohol should not start drinking for any or her risk of developing an alcohol- and starches by yeast. Alcohol is also reason. It recommends that if alcohol is associated cancer. Even light drinkers found in some medicines, mouthwash- consumed, it should be done in mod- (those who have no more than one es, and household products (including eration and defines moderate alcohol drink per day) and binge drinkers vanilla extract and other flavorings). drinking as up to one drink per day for have a modestly increased risk of some This fact sheet focuses on cancer risks women and up to two drinks per day for .3–7 Based on data from 2009, associated with the consumption of men. Heavy alcohol drinking is defined an estimated 3.5% of cancer deaths in alcoholic beverages. as having 4 or more drinks on any day or the United States (about 19,500 deaths) According to the National Institute 8 or more drinks per week for women were alcohol related.8 on and , a and 5 or more drinks on any day or 15 Clear patterns have emerged standard in the United or more drinks per week for men. Binge between alcohol consumption and States contains 14.0 grams (0.6 ounces) drinking is defined as consuming 4 or the development of the following types of pure alcohol. Generally, this amount more drinks for women and 5 or more of cancer: of pure alcohol is found in drinks for men in one sitting (typically • : Moderate to • 12 ounces of beer in about 2 hours). heavy alcohol consumption is associ- • 8-9 ounces of malt liquor ated with higher risks of certain head • 5 ounces of wine What is the evidence that alcohol drink- and neck cancers. Moderate drinkers • 1.5 ounces, or a “shot,” of 80-proof ing can cause cancer? have 1.8-fold higher risks of oral cav- distilled spirits (liquor) There is a strong scientific consensus ity (excluding the lips) and pharynx These amounts are used by public that alcohol drinking can cause several (throat) cancers and 1.4-fold higher health experts in developing health types of cancer.1,2 In its Report on risks of larynx (voice box) cancers than guidelines about alcohol consump- Carcinogens, the National Toxicology non-drinkers, and heavy drinkers have tion and to provide a way for people to Program of the US Department of 5-fold higher risks of oral cavity and compare the amounts of alcohol they Health and Human Services lists pharynx cancers and 2.6-fold higher ▶ FACT SHEETS

risks of larynx cancers.4,9 Moreover, • : Moderate to heavy esophagus—for every 10 grams of the risks of these cancers are substan- alcohol consumption is associated with alcohol consumed per day before the tially higher among persons who con- 1.2- to 1.5-fold increased risks of can- first UADT cancer diagnosis there sume this amount of alcohol and also cers of the colon and rectum compared was a 1.09-fold higher risk of a second use tobacco.10 with no alcohol consumption.4,9,14 primary UADT cancer.22 It is less clear • : Alcohol con- Numerous studies have exam- whether alcohol consumption increas- sumption at any level is associated ined whether there is an association es the risk of second primary cancers with an increased risk of a type of between alcohol consumption and at other sites, such as the breast.23–25 esophageal cancer called esophageal the risk of other cancers. Evidence is squamous cell carcinoma. The risks, accumulating that alcohol is associated How does alcohol affect the risk of compared with no alcohol consump- with increased risks of and cancer? tion, range from 1.3-fold higher for of prostate and pancreatic cancers.4,15 Researchers have hypothesized multiple light drinking to nearly 5-fold higher However, for cancers of the ovary, ways that alcohol may increase the risk for heavy drinking.4,9 In addition, prostate, , uterus, and bladder, of cancer, including: people who inherit a deficiency in either no association with alcohol use • metabolizing (breaking down) an enzyme that metabolizes alcohol has been found or the evidence for an in alcoholic drinks to acet- have been found to have substantially association is inconsistent. aldehyde, which is a toxic chemical increased risks of esophageal squa- Alcohol consumption has also been and a probable human carcinogen; mous cell carcinoma if they consume associated with decreased risks of kid- can damage both DNA alcohol.11 ney cancers16–18, and non-Hodgkin (the genetic material that makes up • : Heavy alcohol con- lymphoma19,20 in multiple studies. genes) and proteins sumption is associated with approxi- However, any potential benefits of • generating reactive oxygen species mately 2-fold increased risks of alcohol consumption for reducing (chemically reactive molecules that two types of liver cancer (hepato- the risks of some cancers are likely contain oxygen), which can damage cellular carcinoma and intrahepatic outweighed by the harms of alcohol DNA, proteins, and lipids (fats) in the ).4,9,12,13 consumption. In fact, a recent study body through a process called oxidation • Breast cancer: Epidemiologic studies that included data from more than • impairing the body’s ability to have consistently found an increased 1000 alcohol studies and data sources, break down and absorb a variety of risk of breast cancer with increasing as well as death and disability records nutrients that may be associated with alcohol intake. Pooled data from 118 from 195 countries and territories cancer risk, including vitamin A; individual studies indicates that light from 1990 to 2016, concluded that the nutrients in the vitamin B complex, drinkers have a slightly increased optimal number of drinks to consume such as folate; vitamin C; vitamin D; (1.04-fold higher) risk of breast can- per day to minimize the overall risk vitamin E; and carotenoids cer, compared with nondrinkers. The to health is zero.21 That study did not • increasing blood levels of estro- risk increase is greater in moderate include data on kidney cancer or non- gen, a sex hormone linked to the risk drinkers (1.23-fold higher) and heavy . of breast cancer drinkers (1.6-fold higher).4,9 An analysis Alcohol consumption may also be Alcoholic beverages may also con- of prospectivedata for 88,000 women associated with an increased risk of tain a variety of carcinogenic con- participating in two US cohort stud- second primary cancers. For exam- taminants that are introduced during ies concluded that for women who ple, a meta-analysis of data from 19 fermentation and production, such as have never smoked, light to moderate studies showed that among patients nitrosamines, fibers, phenols, drinking was associated with a 1.13- with cancer of the upper aerodiges- and hydrocarbons. fold increased risk of alcohol-related tive tract (UADT)—which includes The mechanisms by which alcohol cancers (mostly breast cancer).5 the oral cavity, pharynx, larynx, and consumption may decrease the risks FACT SHEETS

of some cancers are not understood those with the more common form drink comparable amounts of alco- and may be indirect. of ADH.30 hol.31 These increased risks are seen Another enzyme, called aldehyde only among people who carry the Can people’s genes affect their risk of dehydrogenase 2 (ALDH2), metabo- ALDH2 variant and drink alcohol— alcohol-related cancers? lizes toxic acetaldehyde to non-toxic they are not observed in people who A person’s risk of alcohol-related substances. Some people, particular- carry the variant but do not drink cancers is influenced by their genes, ly those of East Asian descent, carry alcohol. specifically the genes that encode a variant of the gene for ALDH2 enzymes involved in metabolizing that encodes a defective form of the Is it safe for someone to drink (breaking down) alcohol.27 enzyme. In people who produce alcohol while undergoing cancer For example, one way the body the defective enzyme, acetaldehyde chemotherapy? metabolizes alcohol is through the builds up when they drink alcohol. As with most questions related to a activity of an enzyme called alcohol The accumulation of acetaldehyde specific individual’s cancer treatment, dehydrogenase, or ADH, which con- has such unpleasant effects (including it is best for patients to check with verts ethanol into the carcinogenic facial flushing and heart palpitations) their health care team about whether metabolite acetaldehyde, mainly in that most people who have inherited it is safe to drink alcohol during or the liver. Recent evidence suggests the ALDH2 variant are unable to con- immediately following chemotherapy that acetaldehyde production also sume large amounts of alcohol and treatment. The doctors and nurses occurs in the oral cavity and may be therefore have a low risk of developing administering the treatment will be influenced by factors such as the oral alcohol-related cancers. able to give specific advice about microbiome.28,29 However, some individuals with the whether it is safe to consume alco- Many individuals of East Asian defective form of ALDH2 can become hol while undergoing specific cancer descent carry a version of the gene for tolerant to the unpleasant effects of treatments. ADH that codes for a “superactive” acetaldehyde and consume large form of the enzyme. This superactive amounts of alcohol. Epidemiologic For full-lnegth article and references, please see ADH enzyme speeds the conversion of studies have shown that such individu- the online version of this article. alcohol (ethanol) to toxic acetaldehyde. als have a higher risk of alcohol-related Among people of Japanese descent, esophageal cancer, as well as of head Source: National Cancer Insititute. ■ those who have this form of ADH have and neck cancers, than individuals a higher risk of than with the fully active enzyme who

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