Overview
- A JAMA Oncology analysis of 29,105 participants in the Nurses' Health Study II found a 45% higher risk of conventional adenomas before age 50 among women reporting the highest ultra-processed food intake versus the lowest.
- The association appeared dose-responsive and persisted after adjusting for body mass index, type 2 diabetes, and fiber intake.
- No link was observed with serrated lesions, a different colorectal precursor that develops more slowly and is less tied to early-onset disease.
- Participants averaged 5.7 daily servings of ultra-processed foods, accounting for about 35% of total calories in the cohort.
- Experts note the study's limits, including its largely white female nurse population and reliance on self-reported diet, and the authors emphasize the need for diverse replication and improved classification of ultra-processed foods as they probe additional risk factors for rising early-onset colorectal cancer.