Ultra-processed Foods and Gastrointestinal Cancer: Epidemiologic Evidence, Mechanistic Pathways, and Clinical Implications.

Ultra-processed foods (UPF), which the NOVA classification defines as industrial formulations composed largely of refined ingredients and additives, now account for a majority of caloric intake in many high-income countries. Epidemiologic evidence suggests that high UPF consumption may contribute to gastrointestinal (GI) malignancies independent of traditional nutrient-based dietary metrics. This review examines associations between UPF intake and colorectal, gastric, esophageal, and pancreatic cancers, integrating mechanisms that support biological plausibility. The association between UPF consumption and colorectal cancer is the most consistent, with a 10% to 30% increased risk among individuals with the highest intake. Evidence also suggests associations with noncardia gastric cancer and esophageal adenocarcinoma although data remain limited. Findings for pancreatic cancer are inconclusive. Mechanistically, ultra-processing may promote carcinogenesis through multiple pathways. Disruption of the food matrix and rapid glycemic absorption may activate insulin and insulin-like growth factor signaling. Low fiber content and additive exposure may alter the gut microbiome, reduce short-chain fatty acid production, impair intestinal barrier integrity, and promote chronic inflammation. Nitrates, nitrites, and emulsifiers in UPFs demonstrate proinflammatory and carcinogenic effects in experimental models. Although observational design limits causal inference, the consistency of epidemiologic associations, dose-response relationships, and supporting mechanistic data suggest UPF reduction may represent a potential GI cancer prevention strategy.