Researchers at Mass General Brigham have linked higher consumption of ultraprocessed foods, which include ready-to-eat items with high levels of sugar, salt, saturated fat, and food additives, to increased risk of precancerous adenomas and early-onset colorectal cancer. The study, published in *JAMA Oncology*, analyzed data from over 20 years of diet and endoscopy records of nearly 30,000 women born between 1947 and 1964.
The participants, who were part of the Nurses’ Health Study II, underwent regular lower endoscopies before turning 50 and completed dietary questionnaires every four years. Women who consumed the most ultraprocessed foods—10 servings per day on average—were found to have a 45% higher risk of developing adenomas compared to those who ate the lowest amount (three servings a day). Adenomas, while not cancerous, are considered precancerous, and their presence is an early warning sign of colorectal cancer.
Although the study does not assert that ultraprocessed foods are the sole cause of early-onset colorectal cancer, it highlights the need for dietary changes to mitigate the growing burden of this disease. Senior author Andrew Chan, a gastroenterologist at Mass General Brigham Cancer Institute, noted that the increased risk seems to be fairly linear, meaning that higher consumption correlates with greater susceptibility to colon polyps. However, researchers caution that diet is not the only factor contributing to the trend, as some individuals with early-onset cancer maintain very healthy diets.
The study, supported by organizations such as Cancer Grand Challenges, Cancer Research UK, the National Institutes of Health, and the American Cancer Society, underscores the importance of further research to identify other risk factors and develop targeted interventions. In the U.S., colorectal cancer is the third-most common cancer and the second leading cause of cancer-related deaths, with an estimated 154,000 new cases and 52,900 deaths expected in 2025. These findings add to the growing body of evidence linking processed foods to various health risks and support ongoing public health initiatives aimed at promoting healthier eating habits.