Does alcohol increase breast cancer risk?

You’re probably already aware that alcohol isn’t good for you, but did you know it’s considered a carcinogen — a harmful substance that can cause cancer?

Alcohol is linked to at least 7 types of cancer — from your mouth to your colon.

It’s also a risk factor you can control. This is especially crucial for women, since even small amounts of alcohol are associated with an increased risk of breast cancer.

“The link between alcohol and breast cancer is particularly worrisome because many women believe moderate drinking is harmless,” says Jennifer Collins, MD, a hematologist-oncologist at Geisinger. “But data shows a consistent association between drinking and higher rates of breast cancer, even among those who drink modest amounts.”

The connection is so strong, the U.S. Surgeon General recently issued an Alcohol and Cancer Risk Advisory and pushed for warning labels on alcoholic beverages.

Find out what that occasional glass of wine to wind down after a long day might mean for your breast and overall health.

How much does alcohol increase breast cancer risk

Alcohol is a well-established risk factor for breast cancer. And studies suggest the increase in risk grows steadily with each additional drink per day.

An analysis of several studies shows women who have 1 drink a day have a 7% to 10% increase in breast cancer risk compared to non-drinkers, while those who consume 2 to 3 drinks a day have about a 20% higher risk. It increases to 32% for those who drink 3 to 4 alcoholic beverages per day — and the risk continues to go up with greater intake.

Even women who consume fewer than 1 drink per day have a 5% increase in breast cancer risk compared to non-drinkers.

“The risk applies to all types of alcohol: wine, beer and spirits — because they all contain the carcinogen ethanol — and is seen across all age groups,” says Dr. Collins. “And drinking amplifies your likelihood of developing breast cancer if you already have other risk factors, like a family history or you’re taking hormone replacement therapy.”

Drinking patterns and frequency influence the risk, too.

Heavy or frequent drinking raises risk more than occasional drinking. So, holding back during the week so you can drink more on the weekend isn’t a good idea.

Why does alcohol increase breast cancer risk?

It’s not clear exactly how alcohol causes cancer, but Dr. Collins offers several possibilities:

• Toxicity. When alcohol is metabolized by the liver, it’s broken down into a toxic carcinogen called acetaldehyde. It damages DNA and can cause affected cells to multiply and develop a cancerous tumor.
• Hormonal effects. Alcohol increases estrogen and other hormone levels in the body. Elevated estrogen stimulates breast cells to grow and divide, raising the likelihood of breast cancer.
• Oxidative stress. Alcohol can heighten oxidative stress, which increases inflammation and damages cell membranes, proteins and DNA.
• Absorption issues. Alcohol interferes with absorption of essential nutrients like folate, which is vital for maintaining healthy cell DNA. And because carcinogens dissolve in alcohol, it’s easier for cancer-causing chemicals like cigarette smoke to be absorbed in the body. 

How much alcohol is too much for women

In general, the less alcohol, the better. Current research suggests any amount of alcohol can harm your health and there’s no safe level of drinking. 

However, for healthy women who choose to drink, the U.S. Centers for Disease Control and Prevention recommend drinking in moderation to reduce — but not eliminate — your risk for breast cancer and other alcohol-related health problems. That equates to no more than one standard drink a day for women (or no more than 7 in a week) and no more than 2 standard drinks a day for men (or no more than 14 per week). 

“Just be mindful of serving sizes, which often exceed a standard drink,” says Dr. Collins. “Some craft beers and certain wines have higher alcohol percentages. So, your single serving — a 12-ounce beer or 5-ounce wine pour — could exceed a standard drink measurement.”

Other ways to reduce breast cancer risk

While there are nonmodifiable breast cancer risk factors like age and family history, there are small changes you can make to your everyday life to keep your risk as low as possible: 

• Get a yearly mammogram, starting at age 40 or earlier if you have personal risk factors 
• Eat a healthy, balanced diet and reduce sugar and ultra-processed foods
• Exercise regularly
• Limit — or eliminate — alcoholic beverages 
• Quit smoking
• Maintain a healthy weight
• Consider risk versus benefit of hormone replacement therapy

“If you choose to drink, talk to your doctor about whether cutting back or stopping altogether is best for your breast health,” says Dr. Collins. “Fortunately, the growing popularity of mocktails and nonalcoholic beers and wines can make it easier to look out for your health while socializing with friends.”

Next steps: 

Learn about breast care at Geisinger
How much alcohol is too much?
Are there early cervical cancer symptoms?