Coffee drinkers have much lower risk of bowel cancer recurrence, study finds
People with bowel cancer who drink two to four cups of coffee a day are much less likely to see their disease come back, research has found.
People with the illness who consume that amount are also much less likely to die from any cause, the study shows, which suggests coffee helps those diagnosed with the UK’s second biggest cancer killer.
Experts said the findings were “promising” and speculated that, if other studies show the same effect, the 43,000 Britons a year diagnosed with bowel cancer may be encouraged to drink coffee. The disease claims about 16,500 lives a year – 45 a day.
A study of 1,719 bowel cancer patients in the Netherlands by Dutch and British researchers found that those who drank at least two cups of coffee had a lower risk of the disease recurring. The effect was dose dependent – those who drank the most saw their risk fall the most.
Patients who had at least five cups a day were 32% less likely than those who drank fewer than two cups to see their bowel cancer return, according to the paper, which was funded by the World Cancer Research Fund (WCRF) and has been published in the International Journal of Cancer.
Similarly, higher levels of coffee consumption also appeared to be closely linked to someone’s chances of surviving.
Again those who drank at least two cups daily had a lower risk of dying compared with those who did not. And, as with the risk of recurrence, those who had at least five cups saw their likelihood of dying fall the most – by 29%.
People in the UK drink an estimated 95m cups of coffee a day.
The research team leader, Dr Ellen Kampman, a professor of nutrition and disease at Wageningen University in the Netherlands, said the disease returned in one in five people diagnosed with it and could be fatal.
“It’s intriguing that that this study suggests drinking three to four cups of coffee may reduce the recurrence of bowel cancer.”
However, she stressed the team had found a strong association between regular consumption of coffee and the disease rather than a causal relationship between them.
“We are hopeful, however, that the finding is real because it appears to be dose dependent – the more coffee drunk, the greater the effect,” she added.
The study is the latest to show that coffee reduces cancer risk. There is already strong evidence that it lowers the risk of liver and womb cancers and some evidence that it does the same for mouth, pharynx, larynx and skin cancers. It is also already associated with a lower risk of developing bowel cancer.
Prof Marc Gunter, a co-author of the study and chair in cancer epidemiology and prevention in the school of public health at Imperial College London, said the findings were “very provocative as we don’t really understand why coffee would have such an effect in bowel cancer patients”.
He added: “But they are also promising as they may point towards a way to improve prognosis and survival among bowel cancer patients.
“Coffee contains hundreds of biologically active compounds which have antioxidative properties and may be protective against bowel cancer.
“Coffee also lowers inflammation and insulin levels – which have been linked to bowel cancer development and progression – and can have potentially beneficial effects on the gut microbiome.
“However, we need more research to go more deeply into the biology of why coffee might have such an effect on bowel cancer prognosis and survival.”
The WCRF has identified chlorogenic acid, which is also found in kale, as an agent that could provide a key part of the explanation because of its role in managing the body’s glucose levels and regulating insulin levels.
Coffee’s emergence as a potential protector against cancer is remarkable because until 2016 the World Health Organization classed it as “possibly carcinogenic” before changing its mind because the evidence did not exist to back that up.
