High-fat Western diets boost gut bacteria that accelerate colorectal cancer in young adults

Researchers from three German institutions have linked the rise of colorectal cancer in adults younger than 50 to Western diets rich in fat and poor in fiber. Their work identified that such diets sustain gut bacteria that convert primary bile acids into deoxycholic acid (DCA), a compound that fuels tumor growth. Using controlled mouse models, the scientists introduced DCA-producing bacteria and observed markedly increased tumor development and cell division compared with bacteria-free controls.

Human stool analyses of more than a thousand participants showed the genetic markers of these bacteria were more common among colorectal-cancer patients. Published in the journal Gut, the study provides direct evidence of causality between diet-induced microbiome shifts and cancer. The authors note the results could inform future therapies, such as microbiome transplants, while emphasizing prevention through healthier eating habits.