A new study has found a significant association between eating large amounts of ultraprocessed foods and a higher risk of early warning signs of colorectal cancer in adults under 50.
Ultraprocessed foods include many ready-to-eat items that contain high levels of sugar, salt, saturated fat, and food additives.
The research was conducted by Mass General Brigham and published in JAMA Oncology.
The study analysed data from nearly 30,000 women enrolled in the Nurses' Health Study II. All participants were born between 1947 and 1964. They completed detailed dietary questionnaires every four years and underwent at least two lower endoscopies before turning 50.
Researchers reported that women who ate about 10 servings of ultraprocessed foods each day had a 45% higher risk of developing adenomas. These are non-cancerous but precancerous polyps in the colon or rectum. Women who consumed around three servings per day had a much lower risk. Adenomas are considered early markers that can lead to colorectal cancer if left untreated.
Senior author Dr Andrew Chan said the study showed a “fairly linear” trend. The more ultraprocessed foods people consumed, the higher their risk of developing colon polyps. He added that the results underline the importance of reducing intake of such foods as part of broader cancer prevention strategies.
Earlier research had connected ultraprocessed foods to colorectal cancer in general, but this is the first study to directly link them to early-onset cases. The team said diet alone cannot fully account for the rise in younger colorectal cancer diagnoses. They noted that metabolic conditions, genetics, and lifestyle choices may also contribute.
Colorectal cancer remains one of the most common cancers in the United States. It is the third-most common cancer overall and the second-leading cause of cancer-related deaths. An estimated 154,000 new cases and 52,900 deaths are expected in 2025.