Inulin mitigates cancer risk factorsDietary fibre counters the oncogenic potential of colibactin-producing Escherichia coli in colorectal cancer.
We set out to understand how dietary choices and genetics influence the cancer-causing potential of certain bacteria, specifically colibactin-producing E. coli, in a mouse model. By examining mice that were colonized with these bacteria and feeding them various diets, including one that was low in carbohydrates and soluble fiber, we observed some striking results. Mice on the low-carbohydrate diet showed an increase in colonic polyps, which are precursors to cancer.
The study revealed that a lack of soluble fiber led to higher levels of mucosal inflammation, which in turn impaired a key signaling pathway in the colon known as PPAR-γ. This disruption not only boosted the growth of colibactin-producing E. coli but also led to significant DNA damage. However, we discovered that administering inulin, a type of soluble fiber, helped counteract these harmful effects. It reduced inflammation and the number of polyps in the affected mice, highlighting the potential protective quality of inulin.
Additionally, in mice that had deficiencies in DNA mismatch repair, we found that E. coli exacerbated polyp formation through another mechanism involving inflammation. This suggests that dietary fiber, particularly inulin, may play a critical role in preventing inflammation-driven carcinogenesis in the gut. By understanding the interplay between diet, microbiome, and cancer risk, we can better appreciate how something as simple as dietary fiber can help shape our health.