Can alcohol cause cancer? Here\’s what the science says

A growing body of evidence has shown links between cancer and drinking alcohol.

In a warning Friday, U.S. Surgeon General Vivek Murthy said cancer risk increases with the number of drinks, but even one drink a day can be dangerous.

Current federal guidelines recommend that if people want to drink alcohol, women should drink no more than one drink per day and men no more than two.

\”Alcohol is a well-established, preventable cause of cancer responsible for about 100,000 cases of cancer and 20,000 cancer deaths annually in the United States,” Murthy said in a statement announcing his advisory.

He added the death toll of alcohol-related cancer deaths was higher than the 13,500 deaths from drunk driving crashes annually in the U.S. But, he said, \”the majority of Americans are unaware of this risk.\”

The science related to drinking has changed in recent years, leading to some confusion among consumers. At one point, moderate drinking was thought to be healthier than not drinking at all. A recent federal report supported that hypothesis, though the finding has been widely criticized. Other data finds that even moderate drinking, as Murthy said, can lead to health problems, including cancer.

How does alcohol cause cancer?

The human body breaks alcohol down into chemicals that can damage DNA, causing cells to grow out of control and become cancerous, according to the National Cancer Institute.

Additionally, alcohol can block the body from breaking down certain nutrients that can increase cancer risk. Alcohol can also increase blood levels of the sex hormone estrogen, which has been linked to higher risk of breast cancer.

The combination of smoking and drinking is \”multiplicative\”—even\” more harmful than adding the potential damage of either one alone, according to the Cancer Institute.

The extent to which drinking alcohol may lower the cancer risk of some cancers isn\’t fully understood and may be indirect, the institute said.

What does research say?

A recent review of alcohol and cancer research by a National Academies of Science, Engineering, and Medicine committee published in December is meant to shape U.S. Dietary Guidelines.

The review found people who drank moderately were less likely to die prematurely from any cause than those who never drank alcohol.

Moderate alcohol drinking was associated with a higher risk of breast cancer, but the review couldn’t draw a conclusion on the association between moderate alcohol consumption and cancers of the mouth, throat, larynx, and esophagus.

Others have disagreed with this assessment, including the National Cancer Institute, which warns that even those who drink no more than one drink per day and those who binge drink have \”modestly increased risk\” for some cancers.