Something strange is happening. And it’s hitting younger people harder than anyone expected. Colon cancer, once thought of as a disease of the aging, is now turning up in people in their 20s, 30s, even late teens. And scientists have been scrambling to answer a haunting question: why now, and why so young?

A new study may have just cracked part of the code. And it leads back to something most of us never saw coming: a common bacterial toxin some of us might have been exposed to before we even lost our baby teeth.

Colon Cancer Cases Are Rising — And Young People Are at Risk

For decades, colon cancer was considered a disease that affected mostly older adults. But over the past several years, that assumption has been turned on its head. Alarming new data show that colorectal cancer is now rising among young adults under 50, so much so that it has become the leading cause of cancer-related deaths in younger men and the second leading cause among women in the same age group.

This isn’t just a small bump in statistics. According to the American Cancer Society, colorectal cancer rates in people under 50 are increasing by 2.4% each year, and deaths are climbing at a rate of 1% annually. That’s despite declining rates among older adults, largely due to better screening and lifestyle changes like reduced smoking.

So what’s behind this generational shift?

Many theories have been proposed—changes in diet, sedentary lifestyles, and disruptions to the gut microbiome among them. But none have offered a definitive answer. Now, a groundbreaking study may have uncovered a crucial piece of the puzzle. Their research points to an unexpected culprit: a bacterial toxin called colibactin, produced by certain strains of E. coli, that may trigger mutations in the colon’s DNA years before cancer is ever diagnosed.

And here’s the twist: it seems that the damage might begin in early childhood, before the age of 10.

The Bacterial Clue Hidden in Childhood

In a study published in Nature, researchers from the University of California San Diego discovered a compelling link between early-life exposure to a bacterial toxin called colibactin and the development of colon cancer in younger adults. Colibactin is produced by certain strains of Escherichia coli (E. coli)—a bacteria commonly found in the human gut.

While E. coli is often associated with food poisoning, not all strains cause immediate illness. Some can live in the gut quietly, going unnoticed. But colibactin, the toxin in question, is far from harmless. It damages DNA and leaves behind a specific mutation pattern, like a biological fingerprint. In fact, when researchers analyzed the cancer genomes of 981 people, they found these mutation signatures were 3.3 times more common in younger patients compared to older ones.

The researchers believe that exposure to colibactin in the first decade of life could dramatically accelerate the timeline of cancer development. “If someone acquires one of these driver mutations by the time they’re 10 years old,” explained study author Dr. Ludmil Alexandrov, “they could be decades ahead of schedule for developing colorectal cancer, getting it at age 40 instead of 60.”

That shift matters. It suggests that colon cancer isn’t just a disease of aging. It may be the result of events that take place much earlier in life, when we’re not even thinking about long-term health risks.

So how are children being exposed to colibactin?

While most people associate E. coli with contaminated food, exposure can also happen through undercooked meat, unwashed produce, or even unpasteurized juice and milk. It’s especially concerning because infection doesn’t always cause symptoms. Meaning, many of us—especially children—could be carrying this bacteria without knowing it, giving colibactin the time it needs to do its silent damage.

Why Young People Are More at Risk

One of the most unsettling aspects of the recent discovery is how early in life the damage may begin. The study’s findings have already suggested that the colibactin-related mutations driving colorectal cancer often occur decades before most people are even screened for the disease.

But why would this exposure hit younger generations harder?

According to the researchers, several shifts in modern childhood could be increasing vulnerability. First, the gut microbiome—the ecosystem of bacteria that lives in our intestines—develops in early childhood and plays a crucial role in immunity and inflammation. Factors like increased C-section births, reduced breastfeeding rates, and a rise in ultraprocessed food consumption may all be disrupting the development of a healthy gut microbiome, potentially making it easier for harmful strains of E. coli to take hold.

There’s also antibiotic use. Broad-spectrum antibiotics, which are often prescribed in childhood, can wipe out beneficial gut bacteria, leaving room for pathogenic strains like colibactin-producing E. coli to dominate.

The result? A younger generation that may be more frequently exposed to the bacterial strains capable of triggering mutations, and at a more vulnerable stage in their development. While previous generations may not have encountered the same environmental and dietary patterns early in life, today’s children might unknowingly be setting the stage for disease in their 30s or 40s.

In short, what used to be a disease of older adults may now be a consequence of exposures and habits from early childhood. Long before any symptoms appear.

Hope for Earlier Detection and Prevention

As alarming as the findings may be, they’re not without a silver lining. Scientists now have a clearer target: colibactin and the mutations it leaves behind.

Using this discovery, researchers are working toward the development of a non-invasive stool test that could detect the DNA “fingerprints” of colibactin-related mutations. Because these mutations begin accumulating years, sometimes decades, before cancer develops, this kind of test could help identify high-risk individuals long before any symptoms appear.

“If you capture colorectal cancer at its early stage, it’s very curable,” says Dr. Ludmil Alexandrov, the lead researcher. By analyzing DNA in stool samples, doctors could eventually pinpoint those with a greater burden of these mutations and recommend earlier or more frequent screening, regardless of age.

This could be a game-changer. Current colorectal screening guidelines are largely age-based, typically starting around age 45 or 50. But if exposure (and damage) can begin as early as age 5 or 10, a personalized risk-based approach becomes all the more critical.

And while the test may take a few years to reach the public, the study already offers a powerful reminder: what happens in childhood doesn’t stay in childhood. Long-term health may be shaped by early microbial exposures, reinforcing the importance of gut health, early nutrition, and prompt attention to unusual symptoms. No matter your age.

My Personal RX on Colon Cancer Prevention at Every Age

Colon cancer is no longer just a concern for older adults. Rates are rising in younger populations, making prevention relevant at every stage of life. The good news is, colon cancer is one of the most preventable cancers when you support your body with the right daily habits. From childhood through older adulthood, gut health, nutrition, and inflammation control all play critical roles in keeping the colon healthy and resilient. Prevention doesn’t start at 50. It starts now.

1. Support the Gut Microbiome Early: A healthy colon starts with a balanced gut. MindBiotic promotes microbial diversity and gut barrier function, helping reduce inflammation and support healthy digestion—key foundations for preventing colon-related disease at any age.
   
2. Start Smart Eating Habits with Mindful Meals: The Mindful Meals cookbook offers over 50 gut-healing recipes that are rich in fiber, antioxidants, and anti-inflammatory ingredients. These meals aren’t just good for digestion—they nourish the colon and help reduce the buildup of toxins and harmful bacteria.
   
3. Eat More Plants, Less Processed Food: Colorful fruits, vegetables, whole grains, legumes, and nuts should be part of every age group’s plate. These foods feed beneficial bacteria and support regular bowel movements, both of which protect the colon from irritation and abnormal cell growth.
   
4. Get Moving, No Matter Your Age: Physical activity improves bowel motility and reduces inflammation. Whether it’s walking, biking, or dancing, moving your body daily helps prevent stagnation in the gut and supports overall colon health.
   
5. Limit Red and Processed Meats Early On: The earlier you reduce red and processed meat intake, the better. These foods are linked to increased colon cancer risk, and limiting them helps establish healthier habits for the long term.
   
6. Stay Consistently Hydrated: Water keeps digestion moving and prevents constipation—a common contributor to colon inflammation. Hydration is a simple yet powerful tool for colon cancer prevention.
   
7. Know Your Family History and Get Screened: If you have a family history of colon cancer, speak with your healthcare provider about earlier screenings. Awareness and early detection can save lives, especially when risk runs in the family.
   
8. Minimize Alcohol and Eliminate Smoking: Both alcohol and tobacco have been linked to increased colorectal cancer risk. Starting these habits early raises your lifetime exposure—so avoiding or eliminating them is one of the best forms of prevention.
   
9. Pay Attention to Gut Symptoms: Don’t ignore chronic bloating, constipation, blood in the stool, or sudden changes in bowel habits. These may signal early signs that should be evaluated—regardless of age.
   
10. Make Prevention a Family Value: When everyone in the household prioritizes gut-healthy meals, movement, and mindful living, prevention becomes a shared lifestyle—not a solo effort. Colon cancer prevention is a lifelong practice that benefits everyone around your table.

Sources:

1. Díaz-Gay, M., Santos, W. D., Moody, S., Kazachkova, M., Abbasi, A., Steele, C. D., Vangara, R., Senkin, S., Wang, J., Fitzgerald, S., Bergstrom, E. N., Khandekar, A., Otlu, B., Abedi-Ardekani, B., De Carvalho, A. C., Cattiaux, T., Penha, R. C. C., Gaborieau, V., Chopard, P., . . . Alexandrov, L. B. (2025). Geographic and age variations in mutational processes in colorectal cancer. Nature. https://doi.org/10.1038/s41586-025-09025-8 
2. Childhood exposure to bacterial toxin may be triggering colorectal cancer epidemic among the young. (2025, April 23). EurekAlert! https://www.eurekalert.org/news-releases/1081222
3. Siegel, R. L., Kratzer, T. B., Giaquinto, A. N., Sung, H., & Jemal, A. (2025). Cancer statistics, 2025. CA a Cancer Journal for Clinicians. https://doi.org/10.3322/caac.21871 
4. Freedman, A. (2025, April 25). Study: Childhood exposure to this bacteria could be driving rates of colorectal cancer in millennials and Gen Xers. Fortune Well. https://fortune.com/well/article/childhood-exposure-bacteria-colorectal-cancer-rates-millennials-gen-xers/