Oral Presentation 6th Australian Health and Medical Research Congress 2012

Regulation of colorectal cancer by dietary factors (#83)

Richard Le Leu 1 2
  1. CSIRO, Adelaide, SA, Australia
  2. Flinders Centre for Cancer Prevention and Control, Flinders University, , SA, Australia

Colorectal cancer (CRC) is one of the leading causes of deaths from cancer in Western countries, and the incidence of this disease is increasing with the steady increase in life expectancy. Modification of diet and lifestyle provide an important opportunity for reducing the risk of developing CRC.  Animal models have been particularly useful for investigating the effect of dietary agents on a range of markers of colorectal health as well as elucidating their mechanisms of action.  Epidemiological studies in humans have shown that dietary fibre can be protective against CRC.  Data obtained from rodent models of CRC have extended these observations to show that resistant starch, a form of dietary fibre abundant in many grains and legumes, appears to be particularly potent at reducing the incidence of chemically-induced colon tumours. Using these models we have also shown that resistant starch consumption can increase butyrate production in the large bowel and this increase correlates with reduced DNA-strand breaks (as measured by comet assay) and an increased apoptotic response to a genotoxic carcinogen.  In contrast, high consumption of red meat is associated with an increased risk of CRC.  In rodents red meat induces pro-mutagenic adducts ‘O6-Methyl-2-deoxyguanosine’ (O6MeG) and DNA-strand breaks in the colon, and this damage is reduced when resistant starch is added to the diet.  On the whole, animal studies can be completed in a relatively short period of time, while they cannot replace human clinical trials, they can be used as a pre-screening tool so that human trials become more directed, with greater chances of success.