A review of dietary patterns and the colorectal polyp-to-carcinoma sequence: polyp occurrence, polyp recurrence, and colorectal cancer

Colorectal cancer (CRC) is the third most common cancer and the second leading cause of cancer-related deaths; it mostly arises from adenomatous and serrated polyps. The role of dietary patterns in the colorectal polyp-to-carcinoma sequence has attracted considerable attention. Diets high in vegetables, fruits, and fibres, as reflected in a priori healthy diet indices, such as the Mediterranean diet score or empirically derived prudent dietary patterns, are consistently associated with a reduced risk of polyp occurrence, and CRC. Conversely, unhealthy diets rich in red and processed meats, refined carbohydrates, and fats are associated with increased polyp occurrence and CRC risk. Epidemiological findings are consistent with mechanism-based indices, such as the Dietary Inflammatory Index. However, evidence linking dietary patterns to polyp recurrence remains comparatively limited. Taken together, the available literature suggests associations between dietary patterns and the polyp-to-carcinoma sequence and supports the rationale for the evaluation of dietary modification as a potentially preventive approach. Because most evidence is observational, well-designed prospective studies, preregistered long-term dietary intervention trials, and mechanistic investigations are needed to clarify causality and to quantify potential effects.