High-fat diets may promote the growth of tumours in the intestine by causing changes to the microbial community in the gut, demonstrates a mouse study in Nature this week. This association is seen in mice with a genetic predisposition for intestinal cancer. The findings suggest that dietary interventions designed to modulate an individual's microbiota may reduce the risk of colorectal cancer development.

Obesity and high-fat diets have been linked to gastrointestinal cancers, although it has been unclear exactly how these factors drive tumour growth. In a mouse model, Melek Arkan and colleagues show that high-fat diets can promote the progression of intestinal tumours independently of obesity. A high-fat diet in conjunction with the presence of the KrasG12Dint gene (a genetic variant that is also frequently mutated in human cancers) causes a shift in the composition of gut microbiota, which reduces immune defences against tumour growth. Treatment with antibiotics or a supplement called butyrate (which is thought to alter bacterial composition and immune functions) is shown to attenuate tumour progression.

Together, these results highlight the complex interactions between diet, the microbiota, the immune response and cancer, and may offer new avenues for cancer prevention.

Article DOI: 10.1038/nature13398