In recent years, a troubling trend has emerged across the globe: more and more young adults are being diagnosed with colorectal cancer, a disease once associated primarily with older generations. According to a September 24, 2025 report by LADbible, early-onset colorectal cancer rates among Millennials and Generation Z in England have surged by approximately 3.6 percent per year over the past decade. This sharp rise is mirrored in several other countries, including New Zealand, Chile, and Puerto Rico, placing the issue squarely in the international spotlight.
Colorectal cancer is now the third most common form of cancer in the United States and the third deadliest, as reported by the National Institutes of Health. The trend began with the younger members of Generation X but has become most visible among millennials, who are now being diagnosed in their 20s, 30s, and early 40s—decades earlier than their parents or grandparents, according to a September 24, 2025 article by the St. Louis Post-Dispatch.
What’s fueling this alarming uptick? That’s the puzzle that researchers like Dr. Yin Cao, ScD, of Washington University School of Medicine in St. Louis, are determined to solve. Dr. Cao is leading an international team, funded by Cancer Grand Challenges—a partnership between Cancer Research UK and the National Cancer Institute (NCI), part of the NIH—to unravel the complex causes behind the global increase in early-onset colorectal cancer. “We don’t yet have all the answers, but factors being investigated include early exposure to processed foods, rising childhood obesity rates, and reduced physical activity,” said Dr. Angad Dhillon, a consultant gastroenterologist, in an interview with Doctify for LADbible.
Across the Atlantic, scientists are also turning to innovative methods to crack the code. In St. Louis, Gary Patti and his team have set up rows of plastic tanks filled with translucent zebrafish, each tank containing a different known or suspected carcinogen. By monitoring which fish develop tumors, they hope to find clues to why so many young people today are getting cancer. Patti’s group is scrutinizing a gamut of factors: medications taken during pregnancy, the spread of ultra-processed foods, disruptions to circadian rhythms from late-night work and screen exposure, and the proliferation of synthetic chemicals.
Diet, it turns out, may play a particularly significant role. Both Dr. Dhillon and Dr. Reshma Rakshit, another consultant gastroenterologist interviewed by LADbible, point to mounting evidence linking colorectal cancer risk to diets high in processed and red meats—especially those low in fiber. Obesity, particularly central or belly fat, sedentary lifestyles, smoking, and heavy alcohol consumption all appear to contribute. “Ultra-processed foods may also play a role by disrupting the gut microbiome,” Dr. Dhillon explained.
The list of foods to watch out for is sobering. Experts recommend cutting back on seven culprits associated with a higher risk of bowel cancer: processed meats such as bacon, sausages, and ham; high intakes of red meat; ultra-processed foods; sugary snacks and drinks; excessive use of sweeteners; alcohol; and caffeine. “Bad news for meat-eaters, then,” the LADbible article quipped, but the science is clear—these dietary patterns are increasingly under the microscope as potential drivers of the cancer surge among young people.
The modern lifestyle, with its relentless pace and technological omnipresence, is also under scrutiny. Disruptions to circadian rhythms—caused by late-night work, global travel, and the omnipresence of screens—may be subtly altering the body’s natural defenses. Meanwhile, the proliferation of synthetic chemicals in everyday products and the use of certain medications during pregnancy are being examined as possible contributors.
But it’s not all doom and gloom. Medical professionals emphasize that there are concrete steps individuals can take to lower their risk. Dr. Rakshit underscores the importance of fiber, noting, “The NHS advises 30 grams a day. This can be in the form of fruits and vegetables—at least five portions per day—wholegrains, nuts, and seeds.” To further support gut health, Dr. Dhillon recommends a diverse, plant-based diet rich in whole grains, fruits, vegetables, legumes, and fermented foods like yogurt or kefir. In addition, drinking between one and a half to two liters of non-caffeinated fluids daily is advised.
Foods that support gut bacteria—such as garlic, onions, broccoli, and Brussels sprouts—are encouraged, as are anti-inflammatory and antioxidant-rich options like oily fish, berries, and green tea. “Staying physically active, maintaining a healthy weight, not smoking, limiting alcohol, and managing stress all play an important role in maintaining a healthy gut too,” Dr. Dhillon added.
While these recommendations are not a one-size-fits-all solution, they offer a roadmap for those hoping to reduce their risk. Still, as Dr. Dhillon cautions, “Please speak with your doctor for more specific guidance.” The complexity of cancer risk means that genetics, environment, and lifestyle all interact in ways that are not yet fully understood.
Researchers are also investigating how antibiotic use in childhood may alter the gut microbiome in ways that influence cancer risk later on. This growing interest underscores the importance of early-life exposures—what children eat, how active they are, and the medications they receive may all have ripple effects decades down the line.
Globally, the urgency to address early-onset colorectal cancer is mounting. In the UK, the rapid rise in cases among Millennials and Gen Z is outpacing most other countries, with only New Zealand, Chile, and Puerto Rico seeing sharper increases. In the US, the disease continues to rank as the third most common and third deadliest cancer, highlighting the scale of the problem.
Despite the daunting statistics, the concerted efforts of international research teams, innovative laboratory studies, and public health campaigns offer hope. By identifying the root causes—be they dietary, environmental, or behavioral—experts aim to reverse the tide and protect future generations from a disease that is striking far too soon.
As scientists like Dr. Cao, Dr. Dhillon, and Dr. Rakshit dig deeper, one thing is clear: modern life, with all its conveniences and complexities, may be reshaping our health in ways we’re only beginning to understand. The challenge now is to translate these findings into actionable steps, empowering individuals and communities to make informed choices for a healthier tomorrow.
