UPFs and early onset colon cancer: Key findings from a major new study

For years, ultraprocessed foods (UPFs) have been implicated in metabolic disease, obesity, and cardiovascular risk.

Now, a new prospective analysis from the Nurses’ Health Study II adds another concern to the list—one that may be particularly relevant as early-onset colorectal cancer (EOCRC) continues to rise.^[]

A closer look at the study

The study, published in JAMA Oncology on November 13, 2025, followed 29,105 female nurses under 50 who underwent at least one lower endoscopy between 1991 and 2015. ^[]

Researchers drew on repeated food-frequency questionnaires to quantify UPF intake—everything from snacks and sugary beverages to ready-to-eat meals—using the Nova classification system.

Over 24 years of follow-up, investigators documented 1,189 early-onset conventional adenomas and 1,598 serrated lesions before age 50.

Interestingly, the link did not extend to serrated lesions, suggesting a potentially distinct biological pathway—or perhaps a specific vulnerability of conventional adenomatous tumorigenesis to metabolic or inflammatory effects of UPFs.

“Our study isn’t cause and effect, so we can’t say that this is definitive,” senior study author Andrew Chan MD, MPH, a gastroenterologist at the Mass General Brigham Cancer Institute in Boston, told CNN.^[] “But it does serve us some clues that what we eat may play a role. So, as we move forward, I think it’s helpful to think about where it is that we can potentially limit our intake..."

Why this matters

Early-onset colorectal cancer is no longer a rarity. Its incidence keeps climbing, and lifestyle factors are often raised as a possible—though not fully understood—driver. ^[]

The consistency of the association—even after controlling for major dietary and metabolic confounders—suggests that UPFs may pose a risk independent of overall diet quality. Whether the culprit is additives, emulsifiers, high glycemic load, low fiber, or some combination remains a question for future work.

But for clinicians counseling patients who increasingly present with polyps or EOCRC, this study provides concrete, quantifiable evidence to support discussions about UPFs, not just vague advice about “diet.”

Your takeaway

For physicians, here are the practical implications:

• Bring diet into earlier conversations. Many patients in their 30s and 40s don’t perceive colorectal cancer risk. This study provides data-backed rationale to start earlier lifestyle counseling.

• Be specific—not just “eat healthier.” Framing recommendations around identifiable UPF categories—packaged baked goods, sweetened beverages, and ready-to-eat meals—may resonate more than general nutrition guidance.

• Consider UPF intake as part of risk assessment. While not ready for formal stratification, a high-UPF pattern may be a meaningful risk flag in younger patients debating early screening or presenting with GI symptoms.

• Normalize prevention beyond fiber and red meat. Patients often know about “good” and “bad” foods, but UPFs are less commonly discussed despite their escalating contribution to total caloric intake.

If nothing else, this evidence gives clinicians another foothold in the preventive counseling conversation—one that patients may actually be able to act on.