Colorectal cancer used to be associated with old age, but diagnoses have become increasingly common in adults aged 50 or younger particularly in high-income countries like the United States. The reason for this trend is unclear, but a new study led by Mass General Brigham researchers, as part of the Cancer Grand Challenges PROSPECT team, suggests an important link to ultra-processed foods that merits closer investigation. By analyzing the diets and endoscopy results from almost 30,000 women, the team found that study participants who reported consuming the highest levels of ultra-processed foods had a 45% higher risk of developing adenomas, which can be precursors of early-onset colorectal cancer, compared to participants who reported consuming the lowest levels. Their results are published in JAMA Oncology.