Fatty food raises risk of colorectal cancer

A German research team has discovered that diets high in fat and low in fiber can raise the risk of colorectal cancer in adults under 50. The study, published in Gut journal, demonstrates a causality between these unhealthy diets, certain gut bacteria, and the development of tumors. The researchers found that fatty foods trigger liver to produce primary bile acids, most of which are reabsorbed, but a small portion reaches the colon.

Here, gut bacteria convert these primary acids into secondary bile acids, such as deoxycholic acid (DCA). Higher intake of fatty foods leads to increased DCA levels in the colon, which can promote tumor growth. To prove this causality, the researchers used mouse models where they implanted DCA-producing bacteria into mice with controlled intestinal microbiomes.

These mice developed more tumors than those without the bacteria. The same effect was observed in human stool samples, with genes of DCA-producing bacteria being more frequently found in individuals with colorectal cancer. This research points to potential treatments for colorectal cancer and emphasizes the importance of preventing the disease through lifestyle changes, such as eating healthier, reducing meat and fatty foods, and avoiding smoking.