Abstract
Colorectal cancer is the second most commonly diagnosed cancer in New Zealand and while the overall incidence of CRC is declining, the changing population demographics means that the prevalence is increasing. Most of these cancers are considered sporadic and current thinking is that their development is driven by an environmental and/or lifestyle factor(s) that promotes chronic inflammation and/or DNA damage with associated changes in the microcellular environment, resulting in pre-cancerous and finally cancerous changes. There is increasing evidence to suggest a role for an individual's gut microbiota in the initiation and progression of sporadic CRC, and diet as one of several lifestyle factors associated with increased risk. This review will examine evidence that links carriage of toxin-producing strains of gut microbiota to the aetiology of CRC, and examine how diet might interact with a toxigenic bacterium to drive (or mitigate) risk of carcinogenesis in infected individuals.