Most people know that heavy drinking can cause health problems. But many people might not know that drinking alcohol also can raise their risk of getting cancer.
Alcohol can act as an irritant, especially in the mouth and throat. Cells that are damaged by the alcohol may try to repair themselves, which could lead to DNA changes that can be a step toward cancer.
Bacteria that normally live in the colon and rectum 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 damage the liver, leading to inflammation and scarring. As liver cells try to repair the damage, they can end up with mistakes in their DNA, which could lead to cancer.
Alcohol may help other harmful chemicals, such as those in tobacco smoke, enter the cells lining the upper digestive tract more easily. This might explain why the combination of smoking and drinking is much more likely to cause cancers in the mouth or throat than smoking or drinking alone.
In other cases, alcohol may slow the body’s ability to break down and get rid of some harmful chemicals.
Alcohol might 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 have low levels of folate. These low levels may play a role in the risk of some cancers, such as breast and colorectal cancer.
Alcohol can raise the levels of estrogen, a hormone important in the growth and development of breast tissue. This could affect a woman’s risk of breast cancer.
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.