The popular snack found to slash bowel cancer risk as scientists highlight ‘long-term health benefit’
SNACKING on walnuts could lower your risk of bowel cancer, new research suggests.
Scientists from the US found that chopping up and sprinkling a handful of the nuts on your porridge each morning might be enough to slash your risk of the disease.
It’s likely down to ellagitannins – plant-based polyphenols found in several types of nuts and berries, including walnuts and pomegranates, the team, whose work was published in Cancer Prevention Research, said.
Once eaten, these compounds are broken down by the gut microbiome into powerful anti-inflammatory molecules known as urolithins.
Since chronic inflammation is linked to cancer, reducing it could help prevent the development and spread of cancer cells.
“Ellagitannins in the walnut are importantly providing the anti-inflammatory and anti-cancer properties that we’re seeing in patients in our clinical trial research,” Dr Daniel W Rosenberg, from UConn School of Medicine, who led the study, explained.
“This is particularly due to the gut’s conversion of ellagitannins into a potent anti-inflammatory agent, urolithin A.”
The team tracked 39 people aged 40 to 65 who were already at elevated risk for bowel cancer.
They were asked to eliminate ellagitannin-rich foods before starting a three-week walnut-rich diet, during which they ate about 28 grams (roughly a handful) of walnuts each day.
At the end of the trial, everyone underwent a colonoscopy – a test that checks inside the bowels.
The researchers found that people with more urolithin A in their urine had lower levels of inflammation in their blood, urine, and bowel polyps.
There was also a drop in vimentin – a protein linked to more aggressive forms of bowel cancer – in those who produced the most urolithin A.
“Urolithin A has a very positive influence on inflammation and maybe even cancer prevention,” Dr Daniel, said.
He added: “Our study provides strong rationale for dietary inclusion of walnut ellagitannins for cancer prevention.
“Nutrients from walnuts can contribute to reduced cancer risk.
“There are many potential benefits one can get from eating walnuts, with so little downside risk, that just grabbing a handful every day is really something that you can easily do for your long-term health benefit.”
Previous studies show walnuts can improve heart health, boost brain function and support help with weight loss.
Bowel cancer is one of the UK’s most common cancers, with around 44,000 people diagnosed each year and 17,000 deaths.
Early symptoms include changes in bowel habits, blood in your poo, weight loss, and stomach pain or lumps.
Cancer Research UK says half of cases could be prevented through healthier lifestyle choices.
Other foods that could lower your risk of bowel cancer
SO yoghurt might have protective benefits, but what else can you try?
Charities like Bowel Cancer UK and Cancer Research UK recommend the following:
- Eat at least five portions of vegetables and fruit every day
- Choose wholegrain varieties of bread, rice and pasta
- Eat more pulses, such as beans and lentils
- Eat some fish, chicken, eggs and tofu, but limit red meat and avoid processed meat
- Drink some milk and eat other dairy foods, but choose low sugar and fat options
- Choose unsaturated oils and spreads instead of butter, and use in small amounts
- Avoid food and drinks high in fat or sugar, such as sweets, cakes, crisps and fizzy drinks
- Eat at least 30g of fibre a day
- Stay hydrated – aim for six to eight glasses of fluid daily
- Lower your alcohol intake