**Surge in Bowel Cancer Among Young Adults Linked to Childhood Diet, Researchers Warn**
Rising rates of bowel cancer among young adults could soon see colorectal cancer become the leading cause of cancer-related deaths in this age group by 2030, according to a new wave of scientific research. Experts now believe that dietary habits formed in childhood may be a critical, if previously overlooked, risk factor fuelling this concerning trend.
Historically regarded as a disease predominantly affecting older people, bowel cancer—also known as colorectal cancer—is now being diagnosed with increasing frequency in the under-50 population. While lifestyle factors such as poor diet, sedentary behaviour, and obesity have been implicated for some time, a recent study is shedding light on a potential new culprit: specific gut bacteria encouraged by processed food consumption during youth.
The research, highlighted by Professor Justin Stebbing of Anglia Ruskin University, reveals that exposure in childhood or adolescence to colibactin—a toxin produced by certain strains of E. coli bacteria—could play a decisive role in the development of particularly aggressive forms of bowel cancer later in life. These strains of E. coli are found to thrive on diets high in processed foods, which are becoming increasingly common among younger generations.
By analysing the DNA of nearly a thousand bowel cancer tumours, researchers discovered a recurring “fingerprint” of mutations that could be traced back to the presence of colibactin. Disturbingly, this pattern of genetic damage was shown to be over three times more prevalent in individuals diagnosed before age 40, compared to those over 70. What’s more, evidence suggests that these mutations can originate within the first ten years of a person’s life.
This striking finding may help to explain why countries such as Argentina, Brazil, and Russia—nations where rates of processed food consumption are swiftly rising—also exhibit higher rates of these colibactin-related genetic changes. The study adds to a growing body of work suggesting that the seeds for bowel cancer may be sown decades before its diagnosis, as children’s guts are first colonised by microorganisms influenced by lifestyle and environmental factors.
Professor Stebbing commented: “Unlike lifestyle risks that accumulate over a lifetime, the damage from colibactin appears to occur within a much narrower window—when the microbiome is still developing in childhood or early adulthood.” He also pointed to possible triggers that could tip the balance in favour of harmful bacterial strains, including frequent antibiotic use (which can disrupt the natural gut flora), highly processed diets, and urban living which limits exposure to a wider range of microbes.
These findings may open the door to new strategies for preventing colorectal cancer in younger populations. Screening programmes could begin targeting not just older adults, but also younger people who carry high-risk bacterial strains. Simple stool tests could help detect the presence of colibactin-producing bacteria, allowing for earlier interventions and potentially life-saving lifestyle advice.
Dietary guidance could also be shaped by this emerging research. Encouraging a diet rich in fibre and low in processed foods from an early age might promote a healthier and more resilient gut microbiome, capable of keeping harmful bacteria in check. Calls to lower the recommended starting age for bowel cancer screening worldwide are likely to gain fresh momentum in light of these findings.
Nevertheless, a number of important questions remain unanswered. For example, why do some individuals with colibactin-producing bacteria go on to develop cancer, while others do not? How do modern environmental factors and lifestyle choices amplify—or perhaps even mitigate—these microbial risks?
What is becoming increasingly clear is that cancer is not purely a genetic or lifestyle-related disease. The microscopic environment of our own guts is now understood to interact dynamically with both our DNA and our daily habits. As researchers around the globe work to unravel the complex interplay between our genes, our environment, and our gut bacteria, it’s evident that the battle against colorectal cancer could well begin many years, if not decades, before symptoms appear.
This evolving perspective on the origins of cancer could ultimately revolutionise how we approach prevention, screening, and education—offering new hope for safeguarding the health of future generations.