Nathan López Bezerra
A new study published in JAMA Oncology adds to growing evidence that ultra-processed foods may be driving the rise in colorectal cancer among younger women. Researchers analyzed data from nearly 30,000 women tracked over 24 years and found that those who consumed the highest amounts of these foods had a 45 percent higher risk of developing precancerous polyps.
Study Details
The research drew on the Nurses’ Health Study II, which has followed tens of thousands of women since 1989. For this analysis, the team focused on 29,105 female participants under age 50 who had completed detailed food questionnaires, undergone at least one lower endoscopy, and had no history of cancer, inflammatory bowel disease, or polyps at the start.
Every four years, the women reported how often they ate various foods. Researchers categorized those foods based on the level of industrial processing. Ultra-processed foods include packaged breads, sweetened beverages, flavored yogurts, breakfast cereals, snack foods, and ready-to-eat meals. These items are often calorie-dense, low in nutrients, and made with additives to improve taste, texture, or shelf life.
Women who ate the most ultra-processed foods — about 5.7 servings per day, or roughly one-third of daily calories — had a 45 percent higher risk of developing precancerous polyps compared with those who ate the least. The association was specific to conventional adenomas, the type of polyp most likely to turn into colorectal cancer over time. No similar link was found for serrated lesions.
The foods most strongly tied to increased risk included sugar-sweetened beverages, ready-to-eat meals, processed meats such as hot dogs and deli slices, as well as breakfast cereals, packaged breads, and bottled condiments.
Possible Mechanisms
Scientists do not yet have direct evidence that ultra-processed foods cause colorectal cancer, but they have several hypotheses. These foods are known to trigger chronic low-grade inflammation throughout the body, including in the gastrointestinal tract. Inflammation can promote DNA damage and mutations, which are early steps toward cancer. Ultra-processed foods also disrupt the gut microbiome because they tend to be low in fiber and high in additives like emulsifiers and artificial sweeteners. This can reduce microbial diversity and encourage harmful bacterial growth. In addition, many of these foods contain advanced glycation end products (AGEs), compounds that form when proteins or fats combine with sugars during high-heat processing. AGEs accumulate in tissues and have been linked to oxidative stress and inflammation.
What This Means for Women
With early-onset colorectal cancer on the rise and routine screening not recommended until age 45, prevention becomes especially important. The study suggests that reducing ultra-processed staples — not just obvious snacks — may help. Packaged breads, sweetened yogurts, cereals, flavored coffee creamers, and bottled sauces were major contributors to intake. Prioritizing fiber-rich whole foods, aiming for 25 to 35 grams of fiber daily from vegetables, beans, whole grains, berries, nuts, and seeds, can support gut health. Keeping sugary drinks to a minimum is also advised.
The article also notes that choosing foods with shorter ingredient lists may help avoid ultra-processed items. Recognizing warning signs — such as persistent changes in bowel habits, blood in the stool, unexplained weight loss, ongoing abdominal cramping, or unusual fatigue — is important regardless of age, because when caught early, colorectal cancer has a survival rate above 90 percent.
Limitations and Context
The study focused exclusively on white female nurses, so more diverse research is needed to understand how these findings apply across different racial, ethnic, and socioeconomic groups. Genetics, access to healthcare, environmental factors, and cultural food traditions all play roles. Still, the core message is that diet is changing cancer risk, potentially decades before symptoms appear. The rise in early-onset colorectal cancer is unfolding alongside major shifts in how food is produced, processed, and consumed.
The article includes a reference to a fiber supplement, organic fiber+ with prebiotic support, described as organic, plant-based, and offering full-body benefits. It also cites one source: the JAMA Oncology study.
