Alcohol and breast cancer risk

Can drinking alcohol cause breast cancer?

Regularly drinking alcohol increases your risk of developing breast cancer.  

• The more you drink, the greater your risk
• Just one alcoholic drink a day can increase your risk, although you can still develop breast cancer even if you do not drink
• To reduce your risk of breast cancer, limit the amount of alcohol you drink

The earlier in your life you start to reduce your drinking, the better.

Reducing your drinking can also help improve your general health and wellbeing, as well as reducing your risk of other cancers and diseases.

Why does alcohol increase breast cancer risk?

It’s not fully understood how alcohol increases the risk of breast cancer. 

It might change the levels of hormones in the body, including oestrogen. Oestrogen can help some breast cancers to grow. 

There may be other ways that alcohol increases the risk of breast cancer, but these are not yet clear.

Does my choice of drink affect my risk?

There isn’t enough evidence to suggest that any type of drink is more of a risk than others. 

We do know that the size, alcohol content and the number of drinks can affect your risk.

What about binge drinking?

It’s not yet known whether binge drinking on one or two days a week leads to a higher risk of breast cancer than drinking the same amount spread evenly throughout the week. 

For women, binge drinking means drinking about six or more units in a few hours.

How much does alcohol increase risk?

The illustration below shows how many women out of 50 will develop breast cancer in their lifetime depending on how many units of alcohol they drink.  

In a group of 50 women who do not drink, about six will probably develop breast cancer in their lifetime. 

In a group of 50 women who drink two units of alcohol a day (for example, a standard glass of wine), about seven will develop breast cancer in their lifetime. 

So drinking two units a day causes one extra woman out of every 50 to develop breast cancer.

National health guidelines for alcohol

UK national health guidelines recommend that women drink no more than 14 units a week. 

This is the equivalent of six pints of lower-strength beer or six 175ml glasses of wine a week. 

If you can, spread your drinks over a few days and have days off drinking each week. 

There’s still a risk of breast cancer associated with this level of drinking. However, you can get breast cancer even if you do not drink, and it can be a useful limit to stick to when beginning to cut down.

How much alcohol is in my drink? 

Units are used as a simple way to express how much alcohol is present in a drink.

The number of units in a drink depends on the size of the drink and its strength, which is usually expressed as a percentage on the bottle or can.

How can I reduce my drinking?

• Swap strong beers or wine for ones with a lower strength 
• If you’re drinking at home, measure out your drinks to track your intake
• It can be useful to track your drinking with an app or diary
• Have an alcohol-free day once or twice a week
• Talk things over with friends or family who can help support you
• Space out your drinks in an evening with soft drinks or mocktails