Alcohol metabolism is the process by which the body breaks down and eliminates alcohol. When alcohol breaks down, its first byproduct is acetaldehyde, a chemical that is itself classified as a carcinogen. Researchers have found that certain genetic mutations can lead the body to break down alcohol faster, resulting in increased levels of acetaldehyde.

There is also considerable evidence that alcohol can trigger the body to release harmful molecules called free radicals. These molecules can damage DNA, proteins and lipids in cells in a process called oxidative stress. My lab has found that free radicals formed from alcohol consumption can directly affect how well cells make and break down proteins, resulting in abnormal proteins that promote inflammation that favors tumor formation.

Alcohol can also directly affect hormone levels in ways that increase cancer risk. For instance, estrogens can increase breast cancer risk. Moderate alcohol drinking can both elevate estrogen levels and promote further drinking. Alcohol also amplifies breast cancer risk by reducing levels of vitamin A, a compound that regulates estrogen.

People who drink and smoke have an elevated risk of developing cancer of the mouth, pharynx and larynx. Alcohol makes it easier for the body to absorb the carcinogens in cigarettes and e-vapes. Smoking by itself can also cause inflammation and induce free radicals that damage DNA.

How much alcohol is safe?

You may be wondering how much alcohol you can safely drink and avoid harm. If you ask clinicians and scientists, you might not like the answer: none.

The Centers for Disease Control and Prevention and American dietary guidelines recommend consuming no more than one drink a day for women and no more than two drinks for men. The National Institute for Alcohol Abuse and Alcoholism and the US surgeon general’s recent advisory have similar recommendations to limit alcohol consumption.

Alcohol consumption is a highly preventable cause of cancer. However, there isn’t currently a way to determine someone’s personal cancer risk from alcohol. Each person’s individual genetic background, lifestyle, diet and other health factors can all influence the effects of alcohol on tumor formation. Nevertheless, rethinking your alcohol drinking habits can help protect your health and reduce your cancer risk.

Pranoti Mandrekar, Professor of Medicine, UMass Chan Medical School

This article is republished from The Conversation under a Creative Commons license. Read the original article.