HOW DOES ALCOHOL RAISE CANCER RISK?

How does alcohol raise cancer risk?

The exact way in which alcohol affects cancer risk isn't completely understood. In fact, there may be several different ways in which it raises risk, and this may depend on the type of cancer.

Damage to body tissues: Alcohol may act as an irritant, especially in the mouth and throat. Cells that are damaged may try to repair themselves, which may lead to DNA changes in the cells that can be a step toward cancer.

In the colon and rectum, bacteria can convert alcohol into large amounts of acetaldehyde, a chemical that has been shown to cause cancer in lab animals.

Alcohol and its byproducts can also directly damage the liver, leading to inflammation and scarring. As liver cells try to repair the damage, they may acquire mistakes in their DNA.

Effects on other harmful chemicals: Alcohol may act as a solvent, helping other harmful chemicals, such as those found in tobacco smoke, to enter the cells lining the upper digestive tract more easily. This may help explain why the combination of smoking and drinking is much more likely to cause cancers in the mouth or throat than either smoking or drinking alone. In other cases, alcohol may slow the body's ability to break down and get rid of some harmful chemicals.

Lower levels of folate or other nutrients: Folate is a vitamin that cells in the body need to stay healthy. Alcohol use may lower the body's ability to absorb folate from foods. This problem can be compounded in heavy drinkers, who often do not get enough nutrients such as folate in their diet. Low folate levels may play a role in the risk of breast and colorectal cancers.

Effects on estrogen or other hormones: Alcohol may raise body levels of estrogen, a hormone important in the growth and development of breast tissue. This may have an effect on a woman's risk of breast cancer.

Effects on body weight: Too much alcohol can add extra calories to the diet, which can contribute to weight gain in some people. Being overweight or obese is known to increase the risks of many types of cancer.

Along with these mechanisms, alcohol may contribute to cancer in other, as of yet unknown, ways.

Source: American Cancer Society