Alcohol includes beverages with ethanol content such as wine, beer and ale, aperitifs, and hard liquor. Moderate to high alcohol intake has been shown to increase the risks of colorectal, upper aerodigestive (mouth, esophagus, larynx, and pharynx), liver, gallbladder, pancreatic, and stomach cancers, as well as melanoma.
On the other hand, some studies have found inverse associations between moderate alcohol consumption and renal cell cancer, thyroid cancer, and non-Hodgkin lymphoma risk. Moderate alcohol consumption has also been linked to reductions in both cardiovascular risk and type 2 diabetes in women. Several studies have found that those who consume an average of one or two drinks per day tend to have lower all cause mortality than those who either abstain from drinking or consume three or more drinks per day.

Breast cancer-related effects of drinking alcohol

Alcohol increases breast cancer risk

Alcohol consumption has been linked to increased risk of breast cancer and reduced survival. Even light drinking (less than one drink per day, on average) has been found to be associated with a modest increase in breast cancer risk. Alcohol intake is associated with increased breast density, a well-established breast cancer risk factor. Alcohol also has been reported to increase the risk of DCIS and LCIS, although not all studies are in agreement.
Alcohol consumption at a very young age is associated with higher likelihood of both benign breast disease and increased breast density, thereby increasing the subsequent risk of premenopausal breast cancer.

Red wine should be limited

The beneficial micronutrients such as resveratrol in red wine do not mitigate the harmful effects of alcohol for the most part. Please see our article on red wine and breast cancer for more information.

Alcohol is associated with more aggressive breast cancer

Alcohol consumption is most likely to be associated with estrogen-responsive (ER+) breast cancer, and lobular breast cancer in particular. However, generally speaking, alcohol appears to increase the aggressiveness and metastatic potential of any breast cancer that does develop. One study reported that chronic ethanol exposure altered both hormone receptor positive (ER+/PR+) and triple negative (ER-/PR-/HER2-) breast cancer cell populations by increasing the fraction of stem cell-like cells more than 20-fold. Alcohol at low concentrations has also been shown to induce proliferation, migration, and invasion in triple negative breast cancer cells. Another study found that breast cancer cells implanted in mice after being exposed to ethanol had much higher rates of growth and metastasis than those not so exposed.
Alcohol consumption has also been found to preferentially increase the risk of triple negative breast cancer in African-American women. However, one 2023 study reported that women with triple negative disease who consumed at least four drinks per week had a reduced risks of recurrence and breast cancer-specific mortality compared to those who did not drink.

Alcohol reduces the treatment effects of tamoxifen

Alcohol consumption has been shown to reduce the beneficial treatment effects of tamoxifen. Please see our article on tamoxifen and alcohol.

Binge drinking carries more risk

The relationship between alcohol and breast cancer risk depends in part on a woman's individual genetic makeup. For example, fast metabolizers of alcohol (who therefore “can't hold their liquor”) have been shown to have a higher risk of breast cancer from a given level of alcohol intake than slow metabolizers.
Consuming several drinks at once is more risky than limiting consumption to one drink per session. One large 2020 study reported higher risk of breast cancer among women who drank during one to three days per week compared to those who drank the same amount over four to seven days. Occasional binge drinking increases breast cancer risk even among moderate drinkers.

Bottom line

Based on the available evidence to date, a glass of red wine with food every other day appears to be a safe level of consumption. Alcohol should be avoided during tamoxifen treatment.

Sources of information provided in this webpage

The information above, which is updated continually as new research becomes available, has been developed based solely on the results of academic studies. Clicking on any of the underlined terms will take you to its tag or webpage, which contain more extensive information.
Below are links to recent studies concerning this food. For a more complete list of studies, please click on alcohol.