Red wine: Medical trial will investigate whether chemical in red grapes can prevent bowel cancer - health benefits and drawbacks of wine

The study – known as Colo-Prevent – has been hailed as a “unique experiment” which could have “big implications” for people at risk of the disease. It will test a chemical mostly found in red grapes – and products made from red grapes, such as wine and juice.

It will also look at other potential treatments to prevent bowel cancer, including aspirin and metformin, a medication prescribed to help people with type 2 diabetes control their blood sugar. It is hoped about 1,300 patients will be taking part in the trial across 60 locations in England and Wales by the start of 2028.

Researchers will use a purified resveratrol, which is a natural compound mostly found in red grapes, as well as blueberries, raspberries and peanuts.

While alcohol carries several potential dangers to drinkers, red wine has previously in moderation been found to have several possible health benefits, largely due to resveratrol, including reduced blood pressure and a lessened chance of heart attacks, as well as a smaller chance of diabetes.

Karen Brown, a professor of translational cancer research at the University of Leicester, is leading the bowel cancer study. Her previous research found purified resveratrol can hinder the growth of cancer cells in small doses.

“With the Colo-Prevent trial, we are embarking on a unique experiment to see how drugs could stop bowel polyps from growing,” Prof Brown said. “This trial could have big implications for how we prevent bowel cancer in people who are most likely to develop the disease as they get older.”

Experts are recruiting people aged between 50 and 73 who have taken part in the NHS bowel screening programme and been found to have bowel polyps, small growths that are usually not serious but can develop into cancer if left untreated.

Patients will have their polyps removed and will be given either aspirin by itself or a combination of aspirin and metformin, for the main trial. Others will take purified resveratrol or a placebo as part of a sub-study.

Those in the aspirin and metformin groups will take the drugs daily for three years, while those on resveratrol or the placebo will take it for one year.

All patients will then be given a colonoscopy – when a long thin tube with a camera on the end is inserted into the bottom to help doctors see inside the colon – to determine if the polyps have started growing again.

Bowel cancer is the fourth most common cancer in the UK, with an estimated 44,000 people each year – or about 120 a day – diagnosed with the disease.

It is not always known what causes it, but the NHS advises people to exercise regularly, eat more fruit and vegetables, drink less alcohol and quit smoking to reduce their risk. Bowel cancer screening is also offered to everyone aged between 54 and 74 every two years.

People are sent faecal immunochemical test (FIT) kits – which look for blood in poo – through the post, allowing them to collect the sample at home.

Dr Iain Foulkes, executive director of research and innovation at Cancer Research UK, which is funding the trial, said: “This trial opens the door to a new era of cancer research, where cancer becomes much more preventable through cutting-edge science.

“The Colo-Prevent trial is one of the biggest trials into therapeutic prevention in the UK. The insights gained from the trial will change how we think about cancer prevention and give more people the chance of longer, better lives, free from the fear of cancer.”

David Trusler, 66, is one of the first patients to take part in the study and said he is doing so for his father, who died with bowel cancer when David was a teenager. Mr Trusler, from Market Harborough in Leicestershire, was diagnosed with prostate cancer 11 years ago, and after successful surgery, it has not returned.

He has been taking part in the NHS bowel screening programme since 2018 and, after receiving an abnormal result earlier this year, a colonoscopy revealed two large polyps.

“My first thought was, ‘oh no, not again’,” Mr Trusler said. “I lost my dad when I was 17 to bowel cancer. We had such a strong bond. I’ll never forget how angry it made me to lose that time with him.

“When my dad was diagnosed in the 1970s, there was no MRIs, no ultrasound. Many of the advances in cancer treatment we have now simply didn’t exist then. I’m taking part in this trial for my dad, to give future generations the kind of treatments he never had.”

Prof Brown added: “Screening has made huge progress in picking up bowel cancers in those most at risk. But to improve outcomes further, we need to prevent more bowel cancers emerging in the first place.

“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. 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.”

The benefits of red wine

Reduced chance of a heart attack

Resveratrol has previously been thought to be good for the heart. According to the Mayo Clinic, in limited amounts wine could prevent coronary artery disease, which can lead to heart attacks. Resveratrol, as an antioxidant called a polyphenol, may be the ingredient that helps protect against cholesterol build-up, and in turn guard against heart attacks.

Reducing blood pressure

Antioxidants in red wine may lower blood pressure, according to webmd. In a few studies of people with slightly elevated blood pressure, red wine extract lowered readings. Both systolic and diastolic pressure improved. It’s thought that the polyphenols were responsible.

Reduced chance of Alzheimer's

Again, the polyphenols are our friends here. They prevent the formation of certain proteins that create toxic plaques that can kill brain cells. These polyphenols can also lessen the plaque toxicity that is already present in the body, thus reducing cognitive decline, says webmd.

Diabetes

Moderate drinks who have a glass of red wine with food has been shown to reduce the risk of type 2 diabetes. However, heavy drinking and drinking without a meal did not have that effect.

The drawbacks of red wine

It’s not all good news though - there’s little chance of getting merlot on prescription.

Cancer risk

Heavy drinking is linked to some cancers, including those of mouth and throat, esophagus, voice box, liver, colon and rectum, and breast, says webmd.com. Chemicals that form in our bodies after drinking alcohol can damage our DNA, which can result in a cell growing uncontrollably and leading to a cancer tumour.

Gout

Wine can trigger gout symptoms, which are caused by high levels of uric acid in the bloodstream. They can extremely painful.

Liver damage

Drinking too much alcohol can damage the liver, leading to conditions such as fatty liver disease and cirrhosis.

Weight gain

Most forms of alcoholic drinks, including red wine, contain a lot of calories per serving. Even people who eat healthily are at risk from weight gain if they drink too much.

Alcohol damage

Binge drinking can lead to injury if people are drunk, as well as opening up more general medical issues due to poor health.

Wine allergies

Red wine is a frequent trigger for people with allergies and intolerances. There are many parts to wine that can cause a reaction in the skin and the digestive system, such as yeast, moulds, and sulphites. Red wine can also be a trigger for asthmatics.

Pregnancy concerns

Red wine - like all alcohol - should be avoided by women who are pregnant and planning to become pregnant, and those who are breastfeeding.