Research has revealed that low-fibre and high-fat diets can significantly raise the chances of early-onset colorectal cancers, with experts calling for greater awareness of the risks for people under 50.

Ohio State University researchers recently presented their findings that environmental factors, such as a “Western diet”, may increase risks for people under the age of 50 because of its impact on bowel bacteria.

Associate professor Graham Newstead, medical director of Bowel Cancer Australia, said the findings aren’t surprising because there is “no doubt that a high-fibre diet is good for you”.

“The food that we are eating these days isn’t the food that our grandparents were. We are no longer sticking a carrot in our back garden, putting some chook manure on it, plucking it when it is ready and eating it,” he said.

“We buy it from a store. It’s wrapped in plastic. It might have been genetically modified to produce more of them and, of course, there are a lot of other additives in our food.”

He said that high-fibre foods work as blotter paper for dead cells that line the bowel.

“Those new cells, if they’re given toxins to play with, then that will affect the new cells that are dividing,” Newstead said.

“Maybe they will divide as abnormal cells and that is when we get the polyps, which line the bowel.

“They can eventually divide into cancer.”

Polyps are small growths of tissue that can lead to cancer, but can be removed during colonoscopies. Photo: Getty

Identifying risk

Bowel cancer, which includes colorectal cancers, is now Australia’s second most deadly cancer for Australians aged between 25 and 44.

Dr Klay Lamprell and her team at Macquarie University’s Australian Institute of Health Innovation found in their research that young people are often overlooked for bowel cancer.

“There is a general perception that [with] bowel cancer, people are taking a long time to be diagnosed,” she said.

“One of the issues is that early-onset colorectal cancer doesn’t present necessarily in the same way that late-onset colorectal cancer does.”

Lamprell said instead of blood in faeces or anal bleeding, people may have symptoms like abdominal pain or changes in bowel habits.

“GPs weren’t looking to investigate cancer in this underage group and what we identified ultimately was that GPs need to actually look for repetitive consults for the same kinds of symptoms, even if they are quite general,” she said.

“GPs offer great medical care, but if patients don’t advocate for themselves and speak up, that can be a factor.”

The Australian government recently lowered the eligibility for bowel cancer screening from 50 to 45.

Other factors

Although diet has played a part in the increased rates of bowel cancer in younger people, which has risen by 266 per cent in adolescents and young adults since the 1980s, there are other factors.

Newstead said that while there have been developments in the treatment of bowel cancers, people should get regular colonoscopies to ensure that any risk is caught early.

“The majority can be treated successfully when detected early. Don’t ignore it because it’s an easy test to do,” he said.

“Girls have their breasts checked and their pap smears so they’re used to getting themselves checked, but the men are often macho and want to just move on.”

Almost 99 per cent of bowel cancer cases are treatable if caught early, while family history contributes to about 30 per cent of all diagnosed cases.

Lamprell said anybody who has persistent symptoms, ranging from blood in faeces, changing bowel habits, unexplained weight loss, extreme tiredness and abdominal swelling, should see a GP.

“The first point of care is to go to your GP with any symptoms that are alarming you,” she said.

“Bowel cancer is occurring early and patients themselves need to drive the conversation if they feel the GP isn’t nominating it as an area of investigation.”

June is Bowel Cancer Awareness Month, when Bowel Cancer Australia raises awareness and funds for the community-led charity