Editor's note: This popular story from the Daily Briefing's archives was republished on June 9, 2023.

While every expert agrees that drinking too much alcohol is unhealthy, the amount of alcohol the average person can safely consume has long been debated, with many experts saying the decision ultimately comes down to a person's risk tolerance, Karen Weintraub reports for USA Today.

What the research says about alcohol consumption

Current dietary guidelines from the U.S. Department of Agriculture (USDA) recommend that, for people who choose to drink, men have no more than two drinks a day and women have no more than one.

George Koob, director of the National Institute on Alcohol Abuse and Alcoholism, stands by those guidelines, though he noted they are currently under review. According to Koob, an increasing number of studies have shown that even drinking a small amount can increase a person's risk of cancer, and 5% of all cancers are caused by alcohol.

Henry Kranzler, director of the Center for Studies of Addiction at the University of Pennsylvania's Perelman School of Medicine, said his research has found that drinking more than roughly one drink a day for both men and women has been associated with lower white and gray matter in the brain, meaning people who drink much more could have cognitive problems.

"The more you drink, the more health risk you incur," he said. "Low levels, like a drink a day on average or less, is probably not meaningfully increasing your risk."

Stanley Hazen, who specializes in preventive cardiovascular medicine at the Cleveland Clinic, said he believes one drink per day is the sweet spot for the heart, and more than that increases the risk of heart attack, stroke, or death.

"By three drinks, you're at more than double the risk," he said. "That's the same magnitude as having diabetes."

According to Eric Rimm, an epidemiologist at the Harvard T.H. Chan School of Public Health who helped author USDA's guidelines, alcohol can help reduce your risk of blood clots and improve glucose control. Because of that, Rimm said he believes it's probably better to drink small amounts of alcohol five nights a week rather than drinking more only on the weekends.

However, liver disease, oncology, and cardiology specialists argue there isn't really a level of alcohol you can consume that's completely safe.

"Any benefit you see from heart disease and diabetes, it's weighed by the increased risk of cancer," said Brian Lee, a liver specialist at the Keck School of Medicine at the University of Southern California. "There's no alcohol that can improve your health and probably any alcohol use is harmful."

Genetics also play a key role in how a person's body responds to alcohol. According to David Streem, a psychiatrist and medical director of the Cleveland Clinic's Alcohol and Drug Recovery Center, between 15% and 25% of white people carry a genetic risk for alcohol abuse while less than 5% of Black Americans carry the same.

"We know there's a lot of genetic risk that is carried from one generation to the next, even if you only have one parent or one side of the family that has significant substance use history," he said.

Streem added that men whose fathers had drinking problems are at the highest risk and shouldn't drink at all. "Once you have a genetic proclivity to develop the disorder, there's only one missing piece and that's exposure to the substance," he said.

How much alcohol is safe to drink?

All experts agree that heavy drinking presents significant health risks. However, experts say the safe amount of alcohol for a person to drink will vary based on an individual's personal risks and tolerance.

According to Kranzler, a woman who consumes the same amount of alcohol as a man is likely to have a higher blood alcohol concentration because women tend to be lighter than men and have lower lean body mass.

People who drink also develop a tolerance, meaning that someone who regularly drinks alcohol will be less impacted by their first drink than someone who doesn't, Kranzler added.

"If you're OK with being potentially at risk, then you responsibly drink a small amount of alcohol," said Marleen Meyers, a breast cancer oncologist at NYU Langone Health.

"If you're 100% risk averse, then you don't smoke, you don't drink, you don't go in the sun, you keep your body weight down, exercise, eat well," she added. "It's an individual choice."

For her patients, and for patients at a high risk of breast cancer, Meyers recommends against any drinking at all.

"We would never say to a patient 'one cigarette occasionally is OK.' It's the same with alcohol," she said. "The advice I would give to anyone who has cancer or wants to reduce the risk of cancer is to drink as sparingly as possible." (Weintraub, USA Today, 2/20)