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Alcohol

People have been drinking alcohol for thousands of years. Alcohol is a part of socializing, celebration and some religious practices. Most adults drink low amounts of alcohol most of the time, while many other people do not drink at all (abstain). In general, men drink alcohol more often and in larger amounts than women.

Alcohol consumption is an important known cause of cancer and has been linked to many other health problems.

Standard drink and alcohol content

When discussing alcohol consumption, healthcare professionals talk about a “standard drink.” One standard drink of alcohol is roughly:

  • one bottle of beer (341 mL or 12 oz)
  • one glass of wine (142 mL or 5 oz)
  • one shot of spirits (43 mL or 1.5 oz)

Alcoholic beverages can contain many different substances, but the main ingredients are ethanol and water. In Canada, a standard drink of beer, wine or spirits has about 13–14 grams of alcohol.

Alcohol isn’t always served in the standard drink measures. In Canada, alcoholic drinks can be served and sold in different sizes with different volumes. The alcohol content can be lower or higher, but the average alcohol content for a standard drink of beer, wine or spirits is:

  • one bottle of beer commonly contains about 5% alcohol
  • one glass of wine commonly contains around 12% alcohol
  • one shot of spirits (hard liquor or liqueurs) contain around 40% alcohol

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Types of cancer linked to alcohol

According to the International Agency on Cancer Research (IARC), there is sufficient evidence that drinking alcohol increases the risk for certain types of cancer, including:

  • head and neck cancers
  • breast cancer
  • colorectal cancer
  • liver cancer

Some evidence also shows that high alcohol intake may increase the risk for pancreatic cancer. There is either not enough evidence of an association between alcohol and other types of cancer, or the evidence is inconsistent.

Head and neck cancers

Alcohol is a very strong risk factor for head and neck cancers, including cancers of the:

  • mouth (oral cavity)
  • throat (pharynx) – particularly the oropharynx and hypopharynx
  • voice box (larynx)
  • esophagus – only squamous cell carcinoma of the esophagus

Most studies show that drinking large amounts of alcohol (greater than 50 g per day or about 4 drinks or more a day) creates a 3 times greater risk for oral and pharyngeal cancers and a 2 times greater risk for, laryngeal and esophageal cancers. The risk for esophageal cancer may be 3–8 times greater with high alcohol intake. Some studies have reported increases in risk at lower levels of alcohol consumption, particularly among women.

Smoking and drinking alcohol together further increase a person’s risk of developing these types of cancer. Drinking alcohol combined with using tobacco increases the risk of head and neck cancers more than either alone. Risk is very high in people who are both heavy drinkers and heavy smokers.

The risk for developing head and neck cancer doesn’t seem to decrease for many years after a person stops drinking.

Breast cancer

Drinking even one alcoholic drink a day can raise the risk for breast cancer by 1.5 times. The risk of breast cancer may increase with every additional drink a woman has each day.

Colorectal cancer

Alcohol is linked with colorectal cancer in both men and women. Regularly drinking moderate to heavy amounts of alcohol can raise the risk for colorectal cancer by 1.4 times.

Liver cancer

Drinking alcohol, especially large amounts of alcohol, can lead to scarring of the liver tissue (cirrhosiscirrhosisAn abnormal condition in which healthy liver tissue is replaced by scar tissue. Signs and symptoms include jaundice, fatigue, loss of appetite and itching of the skin.) and the most common type of liver cancer (hepatocellular carcinoma). Recent evidence shows that drinking 3 or more alcoholic drinks a day increases the risk of liver cancer. Cirrhosis also increases the risk of liver cancer.

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Alcohol and cancer risk

IARC classifies alcohol as a known cancer-causing substance (carcinogen) and drinking alcohol is considered carcinogenic in humans. The exact way that alcohol affects a person’s risk for cancer is not completely understood.

How alcohol increases cancer risk

There are different ways that alcohol may increase cancer risk.

  • People who drink alcohol are exposed to ethanol (the main component of alcoholic beverages) and acetaldehyde, a chemical that is produced when the body breaks down (metabolizes) alcohol. Ethanol and acetaldehyde are both considered to be carcinogens, which may be why alcohol increases cancer risk.
  • Alcohol may act as an irritant, especially in the mouth and throat. Damaged cells may develop changes that can lead to cancer.
  • Alcohol may act as a solvent and help other harmful chemicals, such as those found in tobacco smoke, to enter cells that line the upper gastrointestinal tract. This may be why the combination of smoking and drinking is more likely to cause cancers in the mouth or throat than either smoking or drinking alone.
  • Alcohol may affect the level of certain hormones in the body, such as estrogen, which is a factor in breast cancer development.
  • Alcohol may also interfere with the absorption of some nutrients, such as folate (one of the B vitamins), which may help protect against some types of cancer.
  • Alcohol is generally high in calories. Drinking too much alcohol can add extra calories to the diet and can contribute to weight gain. Adding mixes to an alcoholic beverage can also add calories. Being overweight or obese is linked to an increased risk of certain cancers.
  • Some researchers have suggested that genes involved in alcohol metabolism may put some people at higher risk for alcohol-related cancers.

Level of cancer risk

Studies show that the risk of cancer increases with the amount of alcohol people drink and possibly how often (frequently) they drink. The more you drink, the higher your chance of developing cancer. It doesn’t matter what type of alcohol you drink. Any type of alcohol – beer, wines and spirits – can increase your risk for cancer.

Cancer risk in children

Researchers have studied expectant mothers who drink alcohol during pregnancy and cancer risk in their children.

  • Some studies have shown a possible increased risk of leukemia for children whose mothers drank alcohol during pregnancy, particularly acute myelogenous leukemia (AML). However, more research is needed to confirm this association.
  • A few studies have shown that drinking alcohol during pregnancy was associated with neuroblastoma in children, but more research is needed before this association can be confirmed.

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Alcohol and other health problems

Drinking too much alcohol for a long period of time can lead to a number of other health problems, including:

  • high blood pressure (hypertension)
  • inflammation of the pancreas (pancreatitis)
  • diabetes
  • liver damage (cirrhosis of the liver)

Cirrhosis can lead to lowered liver function and possibly liver failure.

Although drinking a light to moderate amount of alcohol may lower your risk for heart disease, heavy drinking can raise the risk of heart disease. Eating well and being active are better ways to help lower your risk of heart disease. Heavy drinkers and binge drinkers (having 4–5 drinks or more on one occasion) have a higher risk for heart disease and stroke.

Studies have suggested that drinking even a moderate amount of alcohol when you are pregnant may harm the fetus. Drinking during pregnancy causes a range of health problems in the baby, including Fetal Alcohol Spectrum Disorder (FASD). No amount of alcohol use in pregnancy has been proven to be safe.

Alcohol use can also cause injury and accidents.

Alcohol is a drug and can be addictive. Alcoholism is a serious disease that can have a harmful impact on your family, friends and work.

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Reducing your risk

Current evidence does not identify a “safe” level of drinking that does not increase a person’s risk for cancer. However, there are guidelines for adults who wish to lower their risk of cancer from drinking alcohol. The less alcohol you drink, the more you reduce your risk.

  • Keep it to less than 1 alcoholic drink a day for women and less than 2 alcoholic drinks a day for men. The safest option for women who are pregnant, planning to become pregnant or breastfeeding is to not drink alcohol at all.
  • Don’t smoke. Using tobacco and alcohol together is worse for you than using either on its own.

Follow these tips to help reduce the amount of alcohol you drink and your risk of developing certain cancers:

  • Plan ahead and set a limit on the amount you will drink.
  • If you are thirsty, use a non-alcoholic drink like water to quench your thirst.
  • Alternate alcoholic beverages with non-alcoholic drinks like water, soft drinks or juice.
  • Drink alcoholic beverages slowly.
  • Space out your alcoholic drinks.
  • Try to drink lower alcohol drinks, or mix alcoholic drinks with water, low-calorie soft drinks, club soda or juice.
  • Don’t refill your glass until it is empty.
  • Don’t “free pour” drinks because you may be drinking more than you think. Measure the amount of alcohol when you pour drinks so you know how much you are drinking.
  • Don’t try to keep up with your friends “drink for drink” because everyone handles alcohol differently.
  • Avoid playing drinking games because they can make you drink large amounts of alcohol in a short time.
  • Eat before and while you are drinking. Snack with your drinks, but avoid salty snacks like potato chips. Salty snacks can make you thirsty and may cause you to drink more and drink quickly.
  • Do something when you are out with friends to help slow down how much alcohol your drink, like playing pool or dancing. Drink water during these activities.
  • Don’t use alcohol to cope with stress. Go for a walk, take a bath, read a book or listen to some of your favourite music to help you relax.
  • Set small, reasonable goals for yourself. If you are a regular drinker, try to set a goal of a few alcohol-free days each week. Small goals like this will be more successful than trying to cut out alcohol all at once.

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