Recent research from the University of Toronto has highlighted a potential link between low-carb diets and the increased development of polyps in the colon, which could lead to colorectal cancer. This study, involving dietary experiments on mice, scrutinizes the interplay between specific gut bacteria and diet in the context of cancer risk.
The study, published in Nature Microbiology, delves into how different diets impact the gut microbiome and potentially contribute to colorectal cancer development. Researchers explored the effects of three diets—low carb, normal, and Westernized—on mice, alongside three bacterial strains, including a variant of Escherichia coli. Their findings indicated that a low carb, low fiber diet, particularly when combined with the bacterial strain E. coli, increased polyp formation. Polyps can be precursors to colorectal cancer, suggesting a possible dietary risk factor for this type of cancer.
Colorectal cancer remains one of the most diagnosed cancers in the United States. Alarmingly, it has been rising among younger demographics. Data shows a substantial increase in cases for adults aged 30 to 39 from 1999 to 2020. According to the CDC, the disease’s 5-year survival rate is around 64.4%.
The study primarily aimed to uncover how dietary choices might influence cancer risk. It focused on three types of bacteria colonizing mice: Bacteroides fragilis, Helicobacter hepaticus, and E. coli. Researchers observed that these microorganisms could cause DNA damage in intestinal cells, potentially leading to cancer. The low-carb diet specifically allowed harmful bacteria to affect the gut significantly, thinning the mucus layer that normally protects against microbial invasion. This process facilitated DNA damage through compounds like colibactin, increasing the risk of cancer development.
Dr. Marianne Cusick, a colon and rectal surgery expert, noted the compelling nature of these findings. She explained that the mice’s gut environment, affected by the diet, showed increased inflammation and a thinner protective mucus layer, leading to a higher prevalence of polyps—an early indicator of cancer. While acknowledging the excitement around these results, Cusick stressed the need for further research before applying findings to humans. She also suggested that certain soluble fibers might help maintain a healthy gut mucus barrier.
Meanwhile, Dr. Nilesh Vora echoed the need for expanded research, pointing out the ongoing interest in the gut biome’s role in colon cancer. Despite the promising aspects of this animal study, more human-based research is needed to fully understand the implications.
The study represents a significant step in understanding how diet and gut bacteria might contribute to colorectal cancer. While low-carb diets have surged in popularity, this research prompts a closer examination of their potential long-term effects on gut health and cancer risk. Future investigations will hopefully clarify these findings and guide dietary recommendations to mitigate cancer risks.
