The deep-rooted notion that a little bit of alcohol isn’t harmful, and may even be good, for your health has been repeatedly debunked by research on everything from heart disease to dementia to mortality, and yes, certain kinds of cancer. Alcohol raises the risk of developing at least seven types of cancer, and among them, one of the strongest connections is with breast cancer.
In fact, the data suggests any amount of drinking may increase breast cancer risk to some extent. Taking together the results of many studies, “what it drills down to is that drinking about one glass of wine a day, or one standard drink, increases risk of breast cancer over the long term by about 10 percent,” said Anne McTiernan, an internist and epidemiologist who studies cancer prevention at Fred Hutch Cancer Center in Seattle.
Of course, drinking more is riskier for health in general and multiplies the risk for breast cancer, too, she said. McTiernan was a lead author of the landmark 2017 report finding that even light drinking could raise breast cancer risk, telling The Washington Post then that there “is no level of alcohol use that is completely safe in terms of breast cancer.”
This sentiment has since been echoed by the World Health Organization in a widely cited 2023 statement (concluding “no safe amount of alcohol”) and by the American Cancer Society, which in 2020, shifted its stance from recommending moderation to suggesting it’s “best not to drink.”
Recent evidence also helps put the risk of alcohol into context: In 2019, about 16 percent of breast cancer cases could be traced back to alcohol — more than the approximately 10 percent tied to a genetic mutation such as BRCA1 and BRCA2.
Women are often keenly aware of the risk posed by family history, “but you cannot change the gene makeup that you have,” said Carmen Calfa, a breast medical oncologist at Sylvester Comprehensive Cancer Center in the University of Miami Health System. Meanwhile, “dropping that glass of wine or changing the cocktail to a mocktail … is something women can do,” she said, but many “are just not aware of it.”
Why drinking alcohol can increase breast cancer risk
Researchers have many explanations for what underpins the alcohol-cancer connection, but a couple factors seem to play the biggest role when it comes to breast cancer.
The first relates to DNA, or the part of a cell that carries genetic instructions. When you drink an alcoholic beverage, your body breaks down the ethanol it contains into acetaldehyde, a toxic chemical that can damage DNA. “Our bodies have ways to repair DNA damage, but if there’s too much and it’s ongoing, then we can’t keep up with it,” McTiernan said. Messed-up DNA lays the groundwork for cells to reproduce or grow haphazardly, which can prompt cancer cells to form.
Consuming alcohol has also been shown to increase circulating estrogen levels, possibly in part by stimulating aromatase, an enzyme, or protein, found in several body tissues. Its job is to turn androgens, or male sex hormones, into estrogen, Calfa said. More aromatase activity that results in high levels of estrogen in the blood could help fuel estrogen-receptor positive breast cancers — the most common type and also the kind with the strongest link to alcohol consumption.
What determines how alcohol impacts your personal risk
The amount you drink is arguably the most influential factor. We know from a host of studies conducted over the past several decades that the more alcohol you consume, the greater the risk, Calfa said, with one recent analysis suggesting that heavy drinkers have a 52 percent higher risk for breast cancer than non-drinkers. (What those drinks consist of — beer, wine, hard liquor, etc. — doesn’t matter as the body processes the ethanol they contain the same way.)
Drinking at a young age, before the breast cells become fully “differentiated” or mature may also bring greater risk because the breast tissue is more sensitive or susceptible to damage from carcinogens during this window, said Mary Beth Terry, a professor of epidemiology and environmental sciences at Columbia University who researches breast cancer risk factors. You’re also more likely to develop a consistent drinking habit or alcohol use disorder if you pick it up early in life, Terry added, which can lead to greater total consumption.
A final element to consider is your style of drinking. There’s a bit of research showing that binge drinking (consuming four or more drinks in one sitting for women) may uniquely increase breast cancer risk beyond what would be expected from alcohol intake in general. Terry’s recent research suggests the threat of binge drinking may be especially pronounced in younger women, possibly contributing to rising rates of breast cancer under age 40. The reason is not clear, but it may just be tougher for the body to process and flush large quantities of alcohol at once, Terry explained.
Lowering your breast cancer risk from alcohol
While a broad slate of studies have tied greater alcohol consumption to higher breast cancer risk, there’s limited research, by comparison, on how stopping or cutting back on drinking can lower risk, Terry said. As a result, it’s not known to what extent or for how long you may need to quit or reduce drinking to roll back the risk you may have garnered. But overall, the research does suggest that cutting back can only be beneficial.
Based on what experts know about cellular damage and cancer, it’s possible that some amount of damage done by drinking at a young age may be irreversible. But research from Terry’s team has shown that for the common estrogen-receptor positive cancers, lessening alcohol intake can indeed lower risk. Other research has found that among heavy drinkers, drinking less (to any degree) can reduce the likelihood that they get breast cancer over continuing to drink heavily. (Among those who’ve been diagnosed with breast cancer, however, it’s less clear whether drinking or not drinking can impact the risk of recurrence.)
Curtailing your intake — no matter how old you may be or how much you’ve drank in your life — can also help prevent more damage from occurring. After all, the effect of alcohol on breast cancer risk is cumulative, so ultimately, the less exposure over time, the better.
That starts with determining how much you’re drinking, which McTiernan said could be more than you realize. A single drink is defined as 12 ounces of beer, 5 ounces of wine or 1.5 ounces of liquor. But a heavy pour or stiff cocktail could mean you’re consuming the equivalent of two drinks in one glass. Pausing to consider the content of your beverages can help you get a better idea of how much you’re actually consuming, McTiernan said. She added that drinking a glass of water between each drink can naturally slow you down.
It used to be a knee-jerk reaction for Calfa to have a cocktail or glass of wine with dinner, but now she counts her drinks and stops to ask herself, “Do I really want this now?” before reaching for one. She often opts for nonalcoholic options to enjoy the taste of a favorite drink without the alcohol, for instance a zero-proof beer with a burger.
You don’t have to go fully sober to benefit. There are also plenty of other lifestyle behaviors that can help mitigate your breast cancer risk, such as moving more, quitting smoking and eating a balanced diet. When it comes to alcohol, “you can take as much risk as you wish to take,” Calfa said, “but knowing that the risk is there will empower you to make an informed choice.”
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