Gut Bacteria in Childhood May Lead to Early Colon Cancer

With rising rates of colorectal cancer in people under 50 -- cases have doubled in people under 55 over the past 20 years -- medical experts continue to explore the reason for the alarming trend.

Though doctors don’t know exactly why it’s happening, it’s likely a combination of genetic and environmental exposures, and dietary and lifestyle choices. Obesity, diabetes, smoking and unhealthy diets with a lot of processed meat and heavy alcohol use have been associated with colorectal cancer. 

Existing research has also suggested that changes in the gut microbiome are potentially associated with the disease. In a new study, researchers have identified a strong link between a DNA-damaging toxin and colon cancer in younger people. Exposure to the toxin, called colibactin, in early childhood or adolescence may lay the groundwork for colorectal cancer decades later.

How does this toxin come into play? It’s produced by certain strains of E.coli and other bacteria, whose growth is influenced by – you guessed it – diet, inflammation and even some medications. This type of research points to new opportunities for prevention, like screening younger adults for these high-risk bacterial strains using stool tests, as well as continued evidence that diets high in fiber and low in processed foods are the friendliest to the gut microbiome.

The study looked at tissue samples from nearly 1,000 patients with colorectal cancer, and the majority showed mutations indicating colibactin. The patients under age 40 were three to five times more likely to have the mutations compared to those in their 70s and up.

It’s important to note that not everyone who develops colorectal cancer has these colibactin-related mutations, and research continues as to what triggers the trajectory to cancer forming.