Carbohydrates prevent colorectal cancer

Cancer. I believe many people will shudder when they hear the word. Yes, cancer is an incurable disease. For example, colorectal cancer. Some people believe that the carcinogens in nitrosamine compounds are an important cause of human esophageal cancer and gastric cancer, and are also one of the causes of colorectal cancer. Although the reason is not very clear, a large amount of research data shows that the occurrence of colorectal cancer is closely related to eating habits and lifestyle.

It is reported that although the occurrence of colorectal cancer is related to a carbohydrate-rich Western dietary habit, the detailed mechanism is still unclear.

A study published in the journal Cell on July 17 showed that the metabolism of dietary carbohydrates by gut microbes promoted the proliferation of intestinal cells and the formation of tumors in mice with a genetic predisposition to colorectal cancer. Treatment with antibiotics or a low-carbohydrate diet significantly reduced the incidence of colorectal cancer in mice with a genetic predisposition to colorectal cancer, suggesting that perhaps simple measures (antibiotic treatment or a low-carbohydrate diet) could be used to prevent colorectal cancer in humans in the future.

"It is critical to understand how environmental factors, such as gut microbes and diet, interact with genetic factors to influence the progression of colorectal cancer," said Alberto Martin, a researcher at the University of Toronto. The new study shows that gut bacteria interact with a carbohydrate-rich diet to trigger a common type of hereditary colorectal cancer. In a Western diet, carbohydrates make up about half of an adult's daily calorie intake, and previous studies have found that a carbohydrate-rich diet has been associated with the development of colorectal cancer. Colorectal cancer is also frequently associated with mutations in the tumor suppressor gene APC and the MSH2 gene, which is known to play a key role in repairing DNA damage.

However, researchers have been unclear why mutations in pathways involved in DNA repair (APC and MSH2 genes) are more common in colorectal cancer than in other cancers. Because gut microbes are also involved in the development of colorectal cancer, Martin and his team suspected that these mutations might interact with diet to further promote the progression of this type of cancer.

To explore this question, Martin and his collaborators used mice with mutations in the APC and MSH2 genes that are genetically predisposed to colorectal cancer. Treatment with antibiotics or a low-carbohydrate diet reduced intestinal cell proliferation and the number of tumors in the mice's small intestine and colon.

Both treatments also reduced the abundance of certain gut microbes that metabolize carbohydrates to produce butyrate. When butyrate levels were increased in antibiotic-treated mice, cell proliferation and the number of tumors in the small intestine increased.

"Taken together, the results suggest that carbohydrate metabolism by gut microbes generates metabolites that drive intestinal cell proliferation and tumor development in mice susceptible to colorectal cancer. By providing a direct link between genetics and gut microbes, the study suggests that reducing carbohydrates in the diet and altering the gut microbiome may be beneficial for individuals with a genetic predisposition to colorectal cancer."