WHO warns it doesn't take much alcohol to drastically increase cancer risk

The World Health Organization has published new research linking moderate alcohol consumption with a significantly increased risk of developing certain cancers, including colon and breast cancer. The study comes from WHO's International Agency for Research on Cancer (IARC), which also found an increased risk in people described as light drinkers.

The new study focused on Canada, where researchers linked alcohol consumption with one out of seven new cancer cases last year. Of the 7,000 cases the study linked to alcohol use, the researchers say that 24-percent of them were breast cancer, 20-percent were colon cancer, 15-percent were rectal cancer, and 13-percent were liver and oral cancers.

The health risk posed by light and moderate alcohol consumption — defined as no more than two drinks per day — has been a contentious subject. Many studies in recent months have linked this type of alcohol use with increased risks involving everything from heart to brain health.

The researchers behind this new study state that all alcohol consumption comes with risk, at least when focusing on alcohol-related cancers. Study co-author Dr. Jurgen Rehm said, for example, that a single glass of wine daily has been linked to a 6-percent increase in breast cancer risk for women.

Another study co-author, Dr. Kevin Shield, elaborated on how drinking alcohol may increase your risk of developing several types of cancers:

Alcohol causes cancer in numerous ways. The main mechanism of how alcohol causes cancer is through impairing DNA repair. Additional pathways include chronic alcohol consumption resulting in liver cirrhosis, and alcohol leading to a dysregulation of sex hormones, leading to breast cancer. Alcohol also increases the risk of head and neck cancer for smokers as it increases the absorption of carcinogens from tobacco.

The findings are particularly concerning in light of the massive uptick in reported alcohol consumption during the pandemic. Past research found that many people started drinking more when lockdowns occurred, highlighting one aspect of the potential long-term public health consequences that may manifest long after the pandemic is over.