Most people have no idea that alcohol is known to contribute to cancer, but it’s been common knowledge among doctors and cancer researchers for years. Today, the Surgeon General released a report with statistics and recommendations to reduce the risk of cancer from drinking. Here’s what you need to know.
It is rare that scientists will come right out and say that something “causes” cancer (versus, say, “increases the risk of”), but in the case of alcohol, you won’t find much shyness about it. Words like “cause” and “causal” occur 49 times in the new report.
The International Agency for Research on Cancer, the same group that called aspartame “possibly” carcinogenic (group 2B) and red meat “probably” carcinogenic (group 2A), has placed alcoholic beverages in group 1, the straight-up carcinogens, alongside cigarettes and ionizing radiation. They say: “The relationship between alcohol consumption and cancer risk has been known since the beginning of the 20th century.”
The National Cancer Institute’s fact sheet on alcohol states that “there is a strong scientific consensus that alcohol drinking can cause several types of cancer.” They note that alcohol’s metabolic byproducts are carcinogens themselves, that alcohol increases oxidation, that alcohol can increase blood levels of estrogen, which is linked to breast cancer, and that alcohol interferes with our ability to absorb vitamins and nutrients that protect against cancer.
The full picture of exactly how alcohol causes each type of cancer is not fully understood, but the link is clear enough that the Surgeon General estimates there are 100,000 cases of alcohol-linked cancers in the United States each year, including 20,000 deaths. That’s more than the 13,500 alcohol-associated crash fatalities each year.
There are seven types of cancers widely understood to be linked to alcohol:
Breast
Colorectum
Esophagus
Liver
Mouth
Throat
Larynx (voice box)
In the case of breast cancer, over 16% of breast cancers are estimated to be caused by alcohol consumption. For all of these cancers, the risk increases with the amount you regularly drink.
There’s no threshold to the risk, no specific number that you can say “if I drink less than this, I’ll be fine.” That said, this summary of evidence from the University of Florida highlights that:
Light drinking (usually defined as one drink per day, or a little more) increases the risk of esophageal cancer by 160% and breast cancer by 104%
Moderate drinking (usually defined as around two drinks per day) increases the risk of mouth cancer by 180%, throat cancer by 140%, colorectal cancer by 120%, and breast cancer by 123%.
Heavy drinking (usually defined as around 3.5 drinks per day) increases the risk of mouth cancer by 500%, throat cancer by 260%, esophageal cancer by 500%, certain types of liver cancer by 200%, colorectal cancer by 150%, and breast cancer by 160%.
If you recall hearing that light drinking could be good for you, that isn’t necessarily at odds with these results. There is research that has found a reduced risk of heart disease with light drinking, which is why it’s included in the Mediterranean diet. But remember that that diet was based on what people in certain Mediterranean populations ate and drank, and was adopted as a package deal, rather than assembled out of habits that we know for sure are healthy.
The advice from the Surgeon General, and from other public health organizations, is that if you already drink, you might want to reduce your drinking. And if you don’t already drink, you probably shouldn’t start. If you think you may be drinking too much, the CDC has a tool to assess your drinking habits and the Substance Abuse and Mental Health Services Administration has a helpline to find out more about treatment.
