Behind the research: should we drink more coffee to protect against colon cancer?

A Japanese couple drink coffee

Dr Nagisa Mori, World Cancer Research Fund researcherPolyphenols, a type of compound found in many plant foods, have been linked with reduced risk of colon cancer in new research funded by World Cancer Research Fund in Japan.

Polyphenols are found in most plant-based foods, including tea, coffee, cereals, pulses, fruit and vegetables. Dietary polyphenols comprise a large family of more than 500 different compounds and are divided into 4 main classes: flavonoids, phenolic acids, stilbenes and lignans.

What are the main results of the study?

Using funding from World Cancer Research Fund International, we conducted a case-control analysis (looking at cases who developed cancer and healthy controls) using a large dataset from the Japan Public Health Center-based prospective study (JPHC). We investigated the association between the levels of 35 polyphenols in people’s blood plasma and colon cancer risk. However, significant associations were found mainly in the coffee-originated polyphenols.

We looked at 3 polyphenols that came from coffee:

  • 3,4-dihydroxyphenyl propionic acid (also known as dihydrocaffeic acid, this is a polyphenol found in coffee, grapes and other plants).
  • ferulic acid (a polyphenol found in every plant, but in particularly high concentrations in coffee, popcorn and bamboo).
  • caffeic acid (found in eucalyptus bark as well as coffee).

All 3 of these polyphenols found naturally in coffee were associated with a lower risk of colon cancer in the Japanese population we studied. These exciting results suggest that the coffee-originated polyphenols may prevent colon cancer.

These new results support our previous findings (PDF), also conducted in the Japanese population, that women who consumed more than 3 cups of coffee a day had a lower risk of invasive colon cancer (where the cancer cells have grown deeper into the colon).

What’s the biology behind coffee and cancer?

Caffeic acid found in coffee has been shown to suppress colon cancer metastasis (when cancer spreads), have anti-inflammatory effects and could trigger apoptosis (spontaneous death) of colon cancer cells. Ferulic acid also has been shown to suppress colon cancer cell growth. This experimental evidence may explain how coffee helps prevent colon cancer later in life.

We have strong evidence that coffee reduces the risk of:

This new research helps build a picture of whether we can add colon cancer to that list. But because this is the first epidemiological study to observe these links between coffee polyphenols and colon cancer, we believe it needs to be replicated in other large-scale studies and in other populations.

Until we have further evidence, it’s important to remember that the risk of colon cancer can be reduced by:

  • eating more fibre
  • choosing wholegrains
  • eating dairy products
  • being physically active
  • reducing red meat consumption
  • avoiding processed meat
  • avoiding alcohol

> Find out more about Dr Shoichiro Tsugane and Dr Mori’s research
> Read more about our Cancer Prevention Recommendations