A Possible Clue About Rising Colorectal Cancers in the Young

Women who eat higher amounts of ultraprocessed foods may face a greater risk of developing colorectal polyps before age 50, a finding that could help explain rising colorectal cancer rates in younger adults. The research, based on health and dietary records from more than 29,000 US female nurses under 50, found that those who ate nine to 10 servings of ultra-processed foods a day had a 45% higher likelihood of developing polyps compared to those who ate the least, per the Washington Post. Women who ate three servings of ultraprocessed food each day on average had a 3% risk of a precancerous polyp, while women who had 10 or more servings had a 5% risk, per CBS News.

The study, published in JAMA Oncology and led by Dr. Andrew T. Chan of Mass General Brigham Cancer Institute, does not identify a cause-and-effect link between ultraprocessed foods and colon cancer. Instead, it suggests people who consume a lot of ultraprocessed foods—exclusive of factors like BMI, diabetes, and fiber intake—are at higher risk for polyps. As Chan notes, polyps are usually benign. "But we think even the smallest, most benign polyps probably have some malignant potential if they're left in place without any treatment," he tells the Post. In that way, polyps contribute to colon cancer risk.

Chan notes that typical risk factors like obesity and smoking don't fully explain the increase in early-onset colorectal cancer, making diet a key area of interest. While some experts urge caution in interpreting the results, others see the study as important evidence that diet may play a role in the development of early colorectal cancer markers. Ultraprocessed foods, which often have less fiber and more sugar, salt, fat, and additives than less processed or whole foods, now make up more than half the calories in the typical American diet. Though the study group was mostly white, well-educated nurses with good access to health care, outside experts agree the research strengthens the case for eating fewer processed foods and more whole ingredients.