Could a chemical found in red grapes prevent bowel cancer?

Scientists, funded by Cancer Research UK, are finding out if an ingredient commonly found in red grapes could hold the answer to help prevent bowel cancer.  

The star ingredient is a chemical called resveratrol. It’s naturally found in the skin of red grapes, blueberries, raspberries and peanuts. It’s a polyphenol chemical, which means it’s rich in antioxidants. Naturally occurring antioxidants in our bodies can help prevent or delay oxidative stress, which is known to damage our cells. 

In a previous study, led Professor Karen Brown at the University of Leicester, the team found that purified resveratrol can inhibit the growth of cancer cells even at low doses. Through years of research, Brown has found that resveratrol can reach the bowel in an undamaged state and doesn’t get broken down in the stomach. Her team also found that when it reaches the bowel, it can slow down tumour growth in mice and human tissue samples.  

Purified resveratrol isn’t the same as the one found in grape juice or wine. In fact, alcohol is a known cause of cancer and is linked to an increased risk of seven different types of cancer. But what if we had purified resveratrol supplements? Brown’s new trial is seeking to find out if this could be a route to helping prevent bowel cancer.

A new trial

COLO-PREVENT is a new trial led by the University of Leicester and the National Institute for Health and Social Care Research (NIHR) Leicester Biomedical Research Centre. It will test multiple potential prevention drugs for bowel cancer, such as over the counter drugs like aspirin and metformin, and food supplements like resveratrol.  

The participants receiving aspirin or aspirin and metformin will take these drugs daily over three years, while those on resveratrol or the ‘dummy’ tablet will take it for one year. Afterwards, all groups will be given colonoscopies to see if polyps have started growing again, and if so, how big they are compared to the ones removed at the start of the trial.

The call for prevention

Bowel cancer is the 4th most common cancer in the UK, with 120 people getting a diagnosis each day. But more than half of those cases are preventable. People can reduce their risk of bowel cancer by eating less processed and red meat, keeping a healthy weight, drinking less alcohol, and stopping smoking. 

“The best way to prevent bowel cancer right now is to improve our lifestyles – stopping smoking, maintaining a healthy weight, reducing alcohol consumption and having a healthy, balanced diet,” said Brown. 

“But we can enhance those efforts by embracing therapeutic prevention, which uses our growing knowledge of the biology of cancer to find drugs which can stop it in its earliest stages.”  

Investing in research that looks at cancer prevention is just as valuable as investing in cancer treatments.  

Meet the first participant, David

David is 66 years old and is one of the first patients to take part in the COLO-PREVENT trial. David was diagnosed with prostate cancer 11 years ago. 

“To me, being diagnosed with prostate cancer was like being in a Hitchcock horror movie,” David stated. “When I heard the words ‘you have cancer’, I hardly heard anything after that and then when I left the room, my legs went from under me.”   

David was successfully treated by having surgery to remove his prostate. Since then, he’s returned to regularly taking part in bowel cancer screening and received consistent normal results, until recently.  

In June 2024, the screening test showed an abnormal result and he was invited for a colonoscopy. But the doctors didn’t find cancer. To David’s relief, what they saw were two newly formed polyps. However, these polyps could become cancer in the future, and it was at that point that David was invited to join the COLO-PREVENT trial.