Association Between Red and Processed Meat Consumption and Colorectal Cancer Risk: A Scoping Review of the Literature

Background: Colorectal cancer (CRC) represents a major global health burden, with increasing incidence in several Western countries and a rise in early-onset cases. Among modifiable risk factors, red and processed meat consumption has been widely investigated in relation to colorectal carcinogenesis. This scoping review aimed to map epidemiological evidence published between 2015 and 2025 on the association between red and processed meat consumption and CRC risk, summarise proposed biological mechanisms, and explore potential population-specific modifiers of these associations. Methods: This scoping review was conducted in accordance with the PRISMA Extension for Scoping Reviews (PRISMA-ScR). PubMed/MEDLINE was searched for studies published between January 2015 and December 2025. Eligible studies included prospective cohort and case–control studies involving adults, using validated dietary assessment tools and reporting quantitative risk estimates for CRC. Eighteen primary studies met the eligibility criteria and were included in the synthesis. One additional study examining a composite Western dietary pattern rather than quantified meat intake was considered separately as contextual evidence for molecular-subtype stratification. Results: The included studies reported heterogeneous associations between red and processed meat consumption and CRC risk, with findings varying according to meat type, intake contrast, anatomical site, cooking method, and population characteristics. Several studies reported positive associations, whereas others found no statistically significant overall association. In particular, estimates for processed meat and red meat were not uniformly significant across studies, and some positive findings were restricted to specific anatomical sites or molecular subgroups. Proposed biological mechanisms included heme-iron-mediated oxidative stress, endogenous N-nitroso compound formation, the generation of heterocyclic amines and polycyclic aromatic hydrocarbons during high-temperature cooking, and potential interactions with the gut microbiota. Evidence concerning differences by sex, age, geographic setting, and tumour molecular subtype was variable and should be interpreted cautiously. Evidence on dietary patterns and food substitutions also suggested that the broader dietary context may influence the observed associations. Conclusions: Epidemiological findings suggest that red and processed meat consumption may be associated with CRC risk, but the strength and consistency of these associations vary across exposures, populations, and study designs. Proposed biological mechanisms provide plausibility but do not establish causality. These findings are broadly consistent with recommendations to limit red meat and minimise processed meat consumption as part of a balanced, fibre-rich dietary pattern. Further studies using standardised exposure definitions and accounting for cooking practices, dietary substitutions, and relevant population characteristics are needed to clarify the magnitude and variability of these associations.