Just one alcoholic drink a day increases breast cancer risk, our report reveals

X-ray style image of breasts with cancerous growths

Sarah TouleSarah is World Cancer Research Fund’s former Head of Health Information – she ensures that the charity’s knowledge is translated into clear and engaging information for the general public and health professionals.

We know that drinking alcohol increases the risk of several cancers, but surely just one drink a day won’t hurt, right? Actually it could – evidence from our new report shows that even moderate drinkers are putting themselves at an increased risk of breast cancer.

Can only one drink a day really hurt?

There are many ways in which alcohol increases the risk of breast cancer. For example, when we drink alcohol, it is converted into a toxic substance called acetaldehyde which can cause cells to become cancerous by directly damaging DNA.

Unfortunately, bacteria found in the mouth are particularly good at converting alcohol into acetaldehyde, meaning it can build up even if you’ve only been drinking small amounts.

What else did the report find?

Our report also found strong evidence that other lifestyle factors reduce breast cancer risk.

‘Vigorous’ exercise (the type that gets you working up a sweat) helps prevent pre-menopausal breast cancer, while even ‘moderate’ exercise (including, for example, brisk walking) helps prevent the most common post-menopausal type.

So what do we recommend?

The most important thing women can do to reduce their risk of breast cancer is to not drink alcohol – in fact, around one in five breast cancer cases could be prevented every year in the UK by not drinking.

However, with social drinking so ingrained in British culture, we realise that giving up might not be realistic for everyone. If you do choose to drink, you should at least try to reduce your intake – and we have lots of useful tips if you need a helping hand.

Breast cancer may be the most common cancer in women worldwide, but there are steps that women can take which will significantly reduce their risk.


Many of the factors that affect your chances of developing breast cancer are linked to lifestyle. The Preventing Cancer section of our website has all the information.