Can Fiber Save You from a Hidden Cancer Risk?
Colorectal cancer rates are rising among younger adults, leading researchers to investigate the role of diet and gut bacteria in its development. A recent study from the University of Toronto explored how dietary fiber might reduce colorectal cancer risk linked to harmful gut bacteria, specifically certain strains of Escherichia coli (E. coli). The findings were published in Nature Microbiology on March 3, 2025.
Study Overview
The research team, led by Alberto Martin from the Department of Immunology at the University of Toronto, used a mouse model to examine the effects of three diets: low-carb, standard, and Westernized. They also introduced specific gut bacteria, including Bacteroides fragilis, Helicobacter hepaticus, and a toxin-producing strain of E. coli known as pks+ E. coli.
Key Findings
The study showed that mice on a low-carb, low-fiber diet exposed to pks+ E. coli had more polyps and tumors than those on other diets. Notably, pks+ E. coli is present in about 60% of colorectal cancer cases. The low-carb diet also weakened the colon’s protective mucus layer, allowing the E. coli toxin, colibactin, to damage DNA. This led to DNA damage, increased inflammation, and cellular aging — all significant risk factors for cancer.
The Role of Dietary Fiber
Interestingly, when dietary fiber was added to the low-carb diet, tumor growth decreased, and inflammation improved. The researchers suggest that fiber supports gut health by reducing inflammation and protecting against the harmful effects of pks+ E. coli.
Implications and Future Research
The findings raise concerns about low-carb diets lacking fiber, such as the keto diet, which is popular for weight loss. The researchers plan to investigate which types of dietary fiber offer the most protection and whether these effects occur in humans.
Conclusion
This study underscores the complex relationship between diet, gut bacteria, and cancer risk. Maintaining a balanced, fiber-rich diet may help reduce the chances of developing colorectal cancer by supporting gut health and minimizing inflammation.
The researchers concluded, “The combination of impaired DNA repair and inflammation amplifies the cancer-promoting effects of pks+ E. coli. These findings highlight the need to consider diet and genetics in understanding colorectal cancer risks.”
Source: Inputs from various media Sources
Priya Bairagi
Reviewed by Dr Aarti Nehra (MBBS, MMST)
I’m a pharmacist with a strong background in health sciences. I hold a BSc from Delhi University and a pharmacy degree from PDM University. I write articles and daily health news while interviewing doctors to bring you the latest insights. In my free time, you’ll find me at the gym or lost in a sci-fi novel.
