The more ultraprocessed foods you eat, the more potential for colon polyps
A decades-long study of nearly 30,000 women has drawn a measurable line between the modern industrial diet and one of medicine's more troubling trends: colorectal cancer arriving earlier in life than it once did. Researchers at Mass General Brigham found that women consuming ten or more daily servings of ultraprocessed foods faced a 45 percent greater risk of precancerous colon growths compared to those eating far less — a connection that persisted even after accounting for obesity, diabetes, and fiber intake. The finding does not close the question of why younger adults are increasingly diagnosed with this disease, but it places what we eat squarely within that unfinished conversation.
- Colorectal cancer is no longer primarily a disease of the elderly — rates among adults under 50 are climbing, with 154,000 new U.S. cases and nearly 53,000 deaths projected for 2025 alone.
- A 20-year study has now produced the first direct evidence linking ultraprocessed food consumption to precancerous colon growths in younger women, with risk rising in near-perfect proportion to how much processed food they ate.
- The association survived rigorous controls for obesity, diabetes, and low fiber intake, suggesting that something within ultraprocessed foods themselves — beyond their downstream metabolic effects — may be fueling cellular changes in the colon.
- Researchers caution that diet is only part of the answer, noting that some early-onset patients eat well, and that unknown factors are still driving the surge.
- Emerging treatments like GLP-1 drugs are being watched as potential preventive tools, though their role in cancer risk reduction remains speculative and their risks for certain patients unresolved.
Researchers at Mass General Brigham have established, for the first time, a direct link between ultraprocessed food consumption and early-onset colorectal cancer — specifically the precancerous growths known as adenomas that can precede the disease.
The study followed nearly 30,000 women over two decades, tracking their diets through regular questionnaires and comparing outcomes from endoscopies performed before age 50. Women who ate an average of ten or more daily servings of ultraprocessed foods — the sugar-laden, additive-heavy staples of modern supermarket shelves — had a 45 percent higher risk of developing adenomas than those eating around three servings a day. The relationship was strikingly linear: more processed food, more risk.
Critically, the finding held even after researchers controlled for body mass index, Type 2 diabetes, and low fiber intake. Senior author and gastroenterologist Andrew Chan described the association as robust, noting that the dose-response pattern strengthened confidence in the connection. Still, the team was careful to avoid overreach — they see early-onset patients in their clinic who eat well, and acknowledge that diet alone cannot explain the full picture.
The study lands amid a genuine public health alarm. Colorectal cancer is the second-leading cause of cancer death in the United States, and its rise among adults under 50 has unsettled clinicians and researchers alike. Some are now looking at GLP-1 drugs — originally developed for diabetes and weight loss — as potential systemic anti-inflammatory agents that might reduce cancer risk more broadly, though evidence remains preliminary.
For now, the research offers one actionable signal in a complex problem: cutting back on ultraprocessed foods may lower the odds of developing precancerous growths. But the deeper work of understanding why younger people are getting this disease is, by the researchers' own admission, far from finished.
Researchers at Mass General Brigham have found a direct link between what younger women eat and their risk of developing precancerous growths in the colon—a discovery that marks the first time ultraprocessed foods have been connected to early-onset colorectal cancer specifically.
The study tracked nearly 30,000 women born between 1947 and 1964 over two decades, examining their dietary habits and the results of endoscopies performed before age 50. Every four years, participants filled out questionnaires about how much ultraprocessed food they consumed—the kind of ready-to-eat items loaded with sugar, salt, saturated fat, and chemical additives that line supermarket shelves. The researchers then compared the health outcomes of women who ate the most of these foods against those who ate the least.
The numbers were striking. Women who averaged 10 servings of ultraprocessed foods daily had a 45 percent higher risk of developing adenomas compared to those eating just three servings a day. Adenomas are benign growths in the colon or rectum lining, but they matter because they are precancerous—early warning signs that colorectal cancer could follow. The relationship appeared linear: the more processed food someone ate, the greater the risk climbed.
What made this finding particularly significant was that the researchers controlled for other known risk factors. They accounted for body mass index, Type 2 diabetes, and low fiber intake—all things that independently raise cancer risk. Even after factoring these in, the connection between ultraprocessed foods and adenomas held firm. Andrew Chan, the study's senior author and a gastroenterologist at Mass General Brigham, emphasized that the association was robust enough to survive this scrutiny. "The increased risk seems to be fairly linear," he said, meaning the dose matters: eat more processed food, face more potential for polyps.
Yet Chan and his team were careful not to oversimplify. Diet, they acknowledged, is not the whole story. Some ultraprocessed foods are worse than others, and the researchers noted that they see patients in their clinic with early-onset colon cancer who maintain very healthy diets. Something else is driving part of the surge in younger people developing this disease. The team at Mass General Brigham Cancer Institute is now focused on identifying what those other factors might be.
The findings, published in JAMA Oncology, arrive as colorectal cancer in younger adults has become an increasingly urgent public health concern. In the United States, colorectal cancer ranks as the third-most common cancer overall and the second-leading cause of cancer death. For 2025 alone, an estimated 154,000 new cases and roughly 52,900 deaths are projected. The rising incidence in people under 50 has alarmed clinicians and researchers, who are racing to understand why.
Some observers have begun exploring whether newer medications might help prevent the disease. Dr. Marc Siegel, a medical analyst not involved in the research, noted that GLP-1 drugs—medications originally developed for diabetes and weight loss—appear to function as systemic anti-inflammatory agents that improve metabolic function. He suggested that future studies may show these drugs can reduce cancer risk across multiple types, though he cautioned that they may not work for everyone and could carry risks for certain populations, such as those with inflammatory bowel disease.
For now, the Mass General Brigham study offers a clear message: reducing ultraprocessed food consumption could be one strategy to slow the rising tide of early-onset colorectal cancer. But researchers are under no illusion that diet alone will solve the problem. The work of understanding why younger people are getting this disease—and how to stop it—is far from over.
Citações Notáveis
The increased risk seems to be fairly linear, meaning that the more ultraprocessed foods you eat, the more potential that it could lead to colon polyps.— Andrew Chan, senior author and gastroenterologist at Mass General Brigham
Diet isn't a complete explanation for why we're seeing this trend—we see many individuals in our clinic with early onset colon cancer who eat very healthy diets.— Andrew Chan
A Conversa do Hearth Outra perspectiva sobre a história
Why does it matter that this is the first study linking ultraprocessed foods specifically to early-onset cancer, rather than just colorectal cancer in general?
Because early-onset cases in people under 50 are a newer, more alarming trend. We've known for years that diet affects cancer risk overall, but this is the first evidence that what younger people eat might be driving this particular surge. That's a different problem to solve.
The study controlled for obesity and diabetes. Why is that important?
Because those are the obvious culprits—if you're overweight or diabetic, you're already at higher cancer risk. The fact that the ultraprocessed food link remained strong even after accounting for those means diet itself, independent of weight, is doing something harmful. It's not just about calories.
The researchers say diet doesn't explain the whole rise in early-onset cases. What else could be happening?
They don't know yet. That's what makes this incomplete. There could be environmental exposures, changes in the microbiome, infections, or things we haven't even identified. The fact that some of their patients with early-onset cancer eat very healthy diets tells you something else is at work.
A 45 percent increase sounds dramatic. Is it?
It is significant, but context matters. If your baseline risk is low, a 45 percent increase might still be a relatively small absolute number. But when you're talking about a disease that kills tens of thousands of Americans annually, even a percentage shift across a population is real.
What about the GLP-1 drugs mentioned at the end?
That's speculative but intriguing. These drugs reduce inflammation and improve how the body handles metabolism—both things that might prevent cancer. But the researcher was careful to say it's not proven and could have downsides for some people. It's a thread worth pulling, but not a solution yet.