Protective Effects of Plant-Based Diets Against Colorectal Carcinogenesis via Modulation of Key Cellular and Molecular Mechanisms: A Comprehensive Review of Evidence

Colorectal cancer (CRC) remains one of the most prevalent malignancies worldwide and is the second largest contributor to both incidence and mortality, underscoring the urgent need for effective prevention strategies. This comprehensive review provides the most up-to-date evidence on the protective role of plant-based dietary patterns against CRC carcinogenesis, with particular emphasis on underlying cellular and molecular level mechanisms. Accumulating research demonstrates that plant-based foods, rich in dietary fibre, polyphenols, and multiple other bioactive compounds, promote gut microbial eubiosis, support immune regulation, and modulate adipose tissue homeostasis. These effects are accompanied by intestinal barrier integrity, enhanced production of short-chain fatty acids, and the induction of apoptosis in malignant cells. Moreover, plant-derived nutrients reduce the abundance of pro-inflammatory microbial taxa, decrease oxidative, nitrosative and carbonyl stress, and downregulate pro-inflammatory cytokines and signalling pathways, implicated in tumourigenesis. As a result, plant-based dietary patterns have high potential to reduce CRC risk through modulating the intricate interplay between epigenetics, inflammation, immune dysregulation, metabolic and hormonal disruptions, and gut microbiota, suggesting a highly promising, cost-effective and equitable strategy for CRC prevention.