In a stark warning that implicates our modern food environment, a major new study has found that women under 50 who regularly consume ultra-processed foods face a dramatically higher risk of developing abnormal growths in the bowel that are known precursors to cancer. The research, published in the prestigious journal JAMA Oncology, analyzed data from over 29,000 American nurses over a 26-year period, concluding that those with the highest consumption of UPFs had a 45% increased risk of these precancerous polyps. This finding provides a critical missing piece in the puzzle of why bowel cancer, once a disease of the elderly, is now rapidly escalating among younger generations.

A generation at risk

This new research powerfully aligns with a broader scientific consensus. A systematic review published in Frontiers in Nutrition confirms a definitive link between consumption of ultra-processed foods and increased risk of bowel cancer. This finding aligns with data showing a large increase in bowel cancer rates among younger people since 1995, coinciding with the rise in UPF consumption. In England, diagnoses in the 25-49 age bracket have skyrocketed by more than 50% since the early 1990s. In the United States, projections indicate that colorectal cancer will become the leading cause of cancer death for people under 50 by the year 2030. This study directly confronts this epidemic.

Decoding the science of processed foods

To understand the findings, one must first understand what constitutes an ultra-processed food. Scientists use a classification system called NOVA, which sorts foods into four categories. On one end are unprocessed or minimally processed foods like fresh fruits, vegetables and meats. On the other end are ultra-processed foods: industrial formulations typically containing five or more ingredients, often including substances not commonly used in home cooking, such as emulsifiers, artificial colors, sweeteners and preservatives. Common examples include packaged snacks, sugary cereals, mass-produced breads, processed meats, sweetened drinks and many ready-to-heat meals.

The research was conducted by a team of leading cancer experts. They leveraged the long-running Nurses' Health Study II, tracking the health and dietary habits of 29,105 female nurses from 1989 to 2015. The researchers meticulously analyzed the women's endoscopy results—procedures that examine the colon—and cross-referenced them with detailed food frequency questionnaires filled out every four years.