Colorectal cancer: is the risk on the plate?

The Western diet—characterized by high consumption of red and processed meats, refined products, ultra-processed foods, added sugars, and saturated fats—is consistently associated with a significantly increased risk of CRC. This pattern promotes chronic inflammation, insulin resistance, and alterations in the gut microbiota, creating a pro-tumorigenic environment. 

In contrast, so-called prudent or Mediterranean diets—rich in fruits, vegetables, legumes, whole grains, fish, and plant-based oils—are associated with a significant reduction in risk. Their protective effects rely on multiple mechanisms: high fiber intake, production of short-chain fatty acids such as butyrate, antioxidant properties, and favorable modulation of the gut microbiota.   

Adherence scores to the Mediterranean diet show a reduced risk of CRC, particularly for distal colon cancers. Similarly, dietary patterns high in fiber and low in processed meat are associated with a lower risk of advanced adenomas.   

The authors also highlight the growing body of research on ultra-processed foods. High consumption is associated with an independent increased risk, potentially linked to additives, metabolic disturbances, and high energy density.   

Finally, the interaction between diet and the gut microbiota emerges as a central mediator. Fiber-rich diets promote protective microbial profiles, whereas Western diets are associated with pro-inflammatory dysbiosis.   

Colorectal cancer is strongly influenced by modifiable factors, with diet playing a central role. The current challenge is no longer limited to identifying harmful individual foods, but to promoting protective overall dietary patterns.  

This review aimed to assess the impact of major dietary patterns on CRC risk. The data confirm that Western diets significantly increase risk, while Mediterranean or high-fiber diets exert a measurable protective effect.  

Limitations include the observational nature of the studies and variability in dietary assessment methods. However, the consistency of findings strengthens the biological plausibility of these associations.  

Ultimately, integrating targeted nutritional recommendations with a better understanding of interactions between diet, metabolism, and the microbiota could become a major lever for the primary prevention of colorectal cancer.