For a while now, researchers have boasted the health benefits of red wine, including a lower risk of heart disease and degenerative diseases like Alzheimer’s. In which case, drinking a glass of wine a day seems harmless, even beneficial. But a team of researchers from Harvard TH Chan School of Public Health and Brigham and Women’s Hospital in Boston have busted our wine-infused bubble, finding that just that one glass can increase the risk of breast cancer.

According to the study, alcohol consumption has already been linked to a variety of cancers, including colorectal, liver, and esophageal cancer. But for the most part, that risk was applied more so to heavy drinkers. Now, researchers have expanded the breadth of their analysis to include light to moderate drinkers, examining imbibers all across the nation in what they believe to be the largest study to date.

Researchers looked at how light, standard drinking could influence cancer risk. In this study, a standard drink meant consuming 15 grams of alcohol, or 118 milliliters of wine and/or 355 mL of beer. Furthermore, it meant one drink for women and two for men. Researchers also estimated this risk in conjunction with smoking.

In order to conduct the study, researchers examined data from two large American studies, including the Nurses Health Study (NHS) and the Health Professionals Follow-up Study. Between both studies, there was a total of 88,084 women and 47,881 men for researchers to examine the total risk of colorectal, breast, liver, oral, pharynx, larynx, and esophageal cancer among light drinkers.

Interestingly enough, they found that one standard drink was only associated with a very tiny risk of most types of cancer among both sexes. However, when it came to breast cancer, women were at a significantly higher risk if they had one standard drink a day, regardless of if they were smokers or not. Men, on the other hand, were only at greater risk of cancer if they paired their two drinks with smoking. This was not observed in men who did not smoke.

This, however, is not the first study to find a link between moderate drinking and breast cancer; in fact, similar results were observed by Oxford University’s Million Women Study. Here, researchers observed that for each drink consumed per day, there were 11 cases of breast cancer diagnosed per 1,000 women under the age of 75. Researchers admitted that though this finding seems small, their discovery brought attention to overlooked public health issues.

In response to the latter findings, Dr. Jürgen Rehm from the Centre for Addiction and Mental Health in Toronto said that we cannot ignore this potential risk.

“Light to moderate drinking should be limited to no more than 10g of pure alcohol a day for women and 20g for men (roughly one standard drink a day for women and two standard drinks for men, as defined in most countries),” he told The Guardian.

The Daily Meal reported Professor Sir Ian Gilmore, chair of the Alcohol Health Alliance in the U.K., said it's time to educate the public on the full extent of health risks associated with drinking.

“We know that the public are still largely unaware of the links between alcohol and cancer, particularly the increased risk of developing breast cancer,” he said. “We all have a right to know what we are putting into our bodies and at the minute consumers are being denied this right…We need mandatory health warnings on alcohol labels so that people know the facts and can make an informed choice.”

Source: Willett W, Rimm E, Stampfer M, et al. Light to moderate intake of alcohol, drinking patterns, and risk of cancer: results from two prospective US cohort studies. BMJ. 2015.