High Ultra-Processed Food Intake Linked to Increased Risk of Early-Onset Colorectal Adenomas in Women

Andrew Chan, MD, MPH

Courtesy of Mass General Brigham

Amid a globally increasing incidence of early-onset colorectal cancer (EOCRC), a new study in JAMA Oncology from Mass General Brigham researchers found that high consumption of ultra-processed foods (UPFs) is associated with a significantly increased risk of conventional adenomas, a precursor to EOCRC, in female nurses under 50. The analysis revealed that those with the highest intake of UPFs had a 45% higher risk of developing these precancerous polyps compared to those with the lowest intake.

The primary finding demonstrated a strong association between UPF consumption and the development of early-onset conventional adenomas.

Compared to women in the lowest quintile of UPF intake (average 3 servings/day), those in the highest quintile (average 10 servings/day) had an adjusted odds ratio (AOR) of 1.45 (95% CI, 1.19-1.77; P < .001) for these lesions. In contrast, the study observed no association between UPF intake and the risk of developing serrated lesions (AOR, 1.04; 95% CI, 0.89-1.22; P = .48 for trend).

“Our findings support the importance of reducing the intake of ultra-processed foods as a strategy to mitigate the rising burden of early-onset colorectal cancer,” said senior author Andrew Chan, MD, MPH. “The increased risk seems to be fairly linear, meaning that the more ultra-processed foods you eat, the more potential that it could lead to colon polyps.”

These findings emerged from a robust, long-term analysis of the Nurses’ Health Study II cohort. The prospective study followed 29 105 female nurses who underwent at least one lower endoscopy before the age of 50. The follow-up period spanned 24 years, from June 1, 1991, to June 1, 2015. UPF intake was assessed using validated food-frequency questionnaires administered every four years. On average, UPFs accounted for 34.8% of total daily calories for participants, with a median intake of 5.7 servings per day.

Dr. Chan highlighted the study's robustness in controlling for potential confounding variables.

“One of the strengths of our study was that we had detailed information about other colorectal cancer risk factors in the participants, such as such as body mass index, type 2 diabetes, and low fiber intake,” he said. “Even after accounting for all these other risk factors, the association with ultra-processed foods still held up.”

However, he emphasized that diet is not the sole driver of the EOCRC trend. “Diet isn't a complete explanation for why we're seeing this trend — we see many individuals in our clinic with early onset colon cancer who eat very healthy diets. Identifying other risk factors for early onset colorectal cancer is one of the focuses of the work that we're leading here at the Mass General Brigham Cancer Institute.”

References:

1. Wang C, Du M, Kim H, et al. Ultraprocessed Food Consumption and Risk of Early-Onset Colorectal Cancer Precursors Among Women. JAMA Oncol. Published online November 13, 2025. doi:10.1001/jamaoncol.2025.4777
2. Study Finds Adults Who Consumed More Ultra-Processed Foods Had Higher Rates of Precursors of Early-Onset Colorectal Cancer. News release. Mass General Brigham. November 13, 2025. Accessed November 14, 2025. https://www.massgeneralbrigham.org/en/about/newsroom/press-releases/ultra-processed-foods-early-onset-colorectal-cancer-study