Daily coffee doesn't affect cancer risk - study

If you needed any extra encouragement to indulge in that Flat White this morning, a new study has shown it's not going to do you any fatal harm. 

The study of more than 300,000 people was published in the International Journal of Epidemiology this week, which showed drinking coffee every day neither reduced nor increased a person's risk of developing any cancer.

"We know that coffee is one of the most popular drinks in the world, and there continue to be mixed messages about the role it plays in disease," says senior author Associate Professor Stuart MacGregor. 

"We found there was no real relationship between how many cups of coffee a person had a day and if they developed any particular cancers.

"The study also ruled out a link between coffee intake and dying from the disease."

Coffee contains a complex mixture of bioactive ingredients, including substances such as caffeine and kahweol, which have been shown to display anti-tumour effects in animal studies.

QIMR Berghofer lead researcher, Jue-Sheng Ong, says the study looked at some common individual cancers such as breast, ovarian, lung and prostate cancers and found drinking coffee did not increase or decrease their incidence.

Associate Professor MacGregor says the study had implications for public health messaging around the world.

"The health benefits of coffee have been argued for a long time, but this research shows simply changing your coffee consumption isn't an effective way of protecting yourself from cancer," he says.

It backs up research from the US Food and Drug Administration last year, which indicated consuming coffee posed no significant risk of cancer.

Dr Kathryn Bradbury, a senior research fellow at the University of Auckland, says confusion around whether or not there is a link between coffee and cancer is due to the varied nature of cancer.

"We often talk about cancer as if it is one disease, but really there are many types of cancers and they don't all share the same risk factors," says Dr Bradbury, who specialises in food and nutrition intake in relation to cancer incidence.

Some studies have found that people who drink a lot of coffee have a higher risk of certain cancers, but "it could be that people who drink a lot of coffee lead different lifestyles from people who don't drink coffee and it can be hard to fully take this into account in these large observational studies," says Dr Bradbury.

"This new study is interesting because it looks at genetic variants that are associated with drinking coffee to try to estimate whether drinking coffee truly causes or reduces the risk of cancer. The authors don't find any strong evidence that drinking coffee causes cancer, although we need more data on certain cancer types."

According to Australian and New Zealand food standards, there is no recognised health-based guidance value, such as an Acceptable Daily Intake, for caffeine.